<!doctype html><html lang="en">
 <head>
  <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
  <meta content="width=device-width, initial-scale=1, shrink-to-fit=no" name="viewport">
  <title>P2474R0: `views::repeat`</title>
<style data-fill-with="stylesheet">/******************************************************************************
 *                   Style sheet for the W3C specifications                   *
 *
 * Special classes handled by this style sheet include:
 *
 * Indices
 *   - .toc for the Table of Contents (<ol class="toc">)
 *     + <span class="secno"> for the section numbers
 *   - #toc for the Table of Contents (<nav id="toc">)
 *   - ul.index for Indices (<a href="#ref">term</a><span>, in §N.M</span>)
 *   - table.index for Index Tables (e.g. for properties or elements)
 *
 * Structural Markup
 *   - table.data for general data tables
 *     -> use 'scope' attribute, <colgroup>, <thead>, and <tbody> for best results !
 *     -> use <table class='complex data'> for extra-complex tables
 *     -> use <td class='long'> for paragraph-length cell content
 *     -> use <td class='pre'> when manual line breaks/indentation would help readability
 *   - dl.switch for switch statements
 *   - ol.algorithm for algorithms (helps to visualize nesting)
 *   - .figure and .caption (HTML4) and figure and figcaption (HTML5)
 *     -> .sidefigure for right-floated figures
 *   - ins/del
 *     -> ins/del.c### for candidate and proposed changes (amendments)
 *
 * Code
 *   - pre and code
 *
 * Special Sections
 *   - .note       for informative notes             (div, p, span, aside, details)
 *   - .example    for informative examples          (div, p, pre, span)
 *   - .issue      for issues                        (div, p, span)
 *   - .advisement for loud normative statements     (div, p, strong)
 *   - .annoying-warning for spec obsoletion notices (div, aside, details)
 *   - .correction for "candidate corrections"       (div, aside, details, section)
 *   - .addition   for "candidate additions"         (div, aside, details, section)
 *   - .correction.proposed for "proposed corrections" (div, aside, details, section)
 *   - .addition.proposed   for "proposed additions"   (div, aside, details, section)
 *
 * Definition Boxes
 *   - pre.def   for WebIDL definitions
 *   - table.def for tables that define other entities (e.g. CSS properties)
 *   - dl.def    for definition lists that define other entitles (e.g. HTML elements)
 *
 * Numbering
 *   - .secno for section numbers in .toc and headings (<span class='secno'>3.2</span>)
 *   - .marker for source-inserted example/figure/issue numbers (<span class='marker'>Issue 4</span>)
 *   - ::before styled for CSS-generated issue/example/figure numbers:
 *     -> Documents wishing to use this only need to add
 *        figcaption::before,
 *        .caption::before { content: "Figure "  counter(figure) " ";  }
 *        .example::before { content: "Example " counter(example) " "; }
 *        .issue::before   { content: "Issue "   counter(issue) " ";   }
 *
 * Header Stuff (ignore, just don't conflict with these classes)
 *   - .head for the header
 *   - .copyright for the copyright
 *
 * Outdated warning for old specs
 *
 * Miscellaneous
 *   - .overlarge for things that should be as wide as possible, even if
 *     that overflows the body text area. This can be used on an item or
 *     on its container, depending on the effect desired.
 *     Note that this styling basically doesn't help at all when printing,
 *     since A4 paper isn't much wider than the max-width here.
 *     It's better to design things to fit into a narrower measure if possible.
 *
 *   - js-added ToC jump links (see fixup.js)
 *
 ******************************************************************************/

/* color variables included separately for reliability */

/******************************************************************************/
/*                                    Body                                    */
/******************************************************************************/

	html {
	}

	body {
		counter-reset: example figure issue;

		/* Layout */
		max-width: 50em;			  /* limit line length to 50em for readability   */
		margin: 0 auto;				/* center text within page                    */
		padding: 1.6em 1.5em 2em 50px; /* assume 16px font size for downlevel clients */
		padding: 1.6em 1.5em 2em calc(26px + 1.5em); /* leave space for status flag    */

		/* Typography */
		line-height: 1.5;
		font-family: sans-serif;
		widows: 2;
		orphans: 2;
		word-wrap: break-word;
		overflow-wrap: break-word;
		hyphens: auto;

		color: black;
		color: var(--text);
		background: white top left fixed no-repeat;
		background: var(--bg) top left fixed no-repeat;
		background-size: 25px auto;
	}


/******************************************************************************/
/*                         Front Matter & Navigation                          */
/******************************************************************************/

/** Header ********************************************************************/

	div.head { margin-bottom: 1em; }
	div.head hr { border-style: solid; }

	div.head h1 {
		font-weight: bold;
		margin: 0 0 .1em;
		font-size: 220%;
	}

	div.head h2 { margin-bottom: 1.5em;}

/** W3C Logo ******************************************************************/

	.head .logo {
		float: right;
		margin: 0.4rem 0 0.2rem .4rem;
	}

	.head img[src*="logos/W3C"] {
		display: block;
		border: solid #1a5e9a;
		border: solid var(--logo-bg);
		border-width: .65rem .7rem .6rem;
		border-radius: .4rem;
		background: #1a5e9a;
		background: var(--logo-bg);
		color: white;
		color: var(--logo-text);
		font-weight: bold;
	}

	.head a:hover > img[src*="logos/W3C"],
	.head a:focus > img[src*="logos/W3C"] {
		opacity: .8;
	}

	.head a:active > img[src*="logos/W3C"] {
		background: #c00;
		background: var(--logo-active-bg);
		border-color: #c00;
		border-color: var(--logo-active-bg);
	}

	/* see also additional rules in Link Styling section */

/** Copyright *****************************************************************/

	p.copyright,
	p.copyright small { font-size: small; }

/** Back to Top / ToC Toggle **************************************************/

	@media print {
		#toc-nav {
			display: none;
		}
	}
	@media not print {
		#toc-nav {
			position: fixed;
			z-index: 3;
			bottom: 0; left: 0;
			margin: 0;
			min-width: 1.33em;
			border-top-right-radius: 2rem;
			box-shadow: 0 0 2px;
			font-size: 1.5em;
		}
		#toc-nav > a {
			display: block;
			white-space: nowrap;

			height: 1.33em;
			padding: .1em 0.3em;
			margin: 0;

			box-shadow: 0 0 2px;
			border: none;
			border-top-right-radius: 1.33em;

			color: #707070;
			color: var(--tocnav-normal-text);
			background: white;
			background: var(--tocnav-normal-bg);
		}
		#toc-nav > a:hover,
		#toc-nav > a:focus {
			color: black;
			color: var(--tocnav-hover-text);
			background: #f8f8f8;
			background: var(--tocnav-hover-bg);
		}
		#toc-nav > a:active {
			color: #c00;
			color: var(--tocnav-active-text);
			background: white;
			background: var(--tocnav-active-bg);
		}

		#toc-nav > #toc-jump {
			padding-bottom: 2em;
			margin-bottom: -1.9em;
		}

		/* statusbar gets in the way on keyboard focus; remove once browsers fix */
		#toc-nav > a[href="#toc"]:not(:hover):focus:last-child {
			padding-bottom: 1.5rem;
		}

		#toc-nav:not(:hover) > a:not(:focus) > span + span {
			/* Ideally this uses :focus-within on #toc-nav */
			display: none;
		}
		#toc-nav > a > span + span {
			padding-right: 0.2em;
		}
	}

/** ToC Sidebar ***************************************************************/

	/* Floating sidebar */
	@media screen {
		body.toc-sidebar #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			max-width: 80%;
			max-width: calc(100% - 2em - 26px);
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			color: black;
			color: var(--tocsidebar-text);
			background: inherit;
			background-color: #f7f8f9;
			background-color: var(--tocsidebar-bg);
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
			box-shadow: -.1em 0 .25em var(--tocsidebar-shadow) inset;
		}
		body.toc-sidebar #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
			color: var(--tocsidebar-heading-text);
		}
		body.toc-sidebar #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	/* Hide main scroller when only the ToC is visible anyway */
	@media screen and (max-width: 28em) {
		body.toc-sidebar {
			overflow: hidden;
		}
	}

	/* Sidebar with its own space */
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			color: black;
			color: var(--tocsidebar-text);
			background: inherit;
			background-color: #f7f8f9;
			background-color: var(--tocsidebar-bg);
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
			box-shadow: -.1em 0 .25em var(--tocsidebar-shadow) inset;
		}
		body:not(.toc-inline) #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
			color: var(--tocsidebar-heading-text);
		}

		body:not(.toc-inline) {
			padding-left: 29em;
		}
		/* See also Overflow section at the bottom */

		body:not(.toc-inline) #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) {
			margin: 0 4em;
		}
	}

/******************************************************************************/
/*                                Sectioning                                  */
/******************************************************************************/

/** Headings ******************************************************************/

	h1, h2, h3, h4, h5, h6, dt {
		page-break-after: avoid;
		page-break-inside: avoid;
		font: 100% sans-serif;   /* Reset all font styling to clear out UA styles */
		font-family: inherit;	/* Inherit the font family. */
		line-height: 1.2;		/* Keep wrapped headings compact */
		hyphens: manual;		/* Hyphenated headings look weird */
	}

	h2, h3, h4, h5, h6 {
		margin-top: 3rem;
	}

	h1, h2, h3 {
		color: #005A9C;
		color: var(--heading-text);
	}

	h1 { font-size: 170%; }
	h2 { font-size: 140%; }
	h3 { font-size: 120%; }
	h4 { font-weight: bold; }
	h5 { font-style: italic; }
	h6 { font-variant: small-caps; }
	dt { font-weight: bold; }

/** Subheadings ***************************************************************/

	h1 + h2,
	#subtitle {
		/* #subtitle is a subtitle in an H2 under the H1 */
		margin-top: 0;
	}
	h2 + h3,
	h3 + h4,
	h4 + h5,
	h5 + h6 {
		margin-top: 1.2em; /* = 1 x line-height */
	}

/** Section divider ***********************************************************/

	:not(.head) > :not(.head) + hr {
		font-size: 1.5em;
		text-align: center;
		margin: 1em auto;
		height: auto;
		color: black;
		color: var(--hr-text);
		border: transparent solid 0;
		background: transparent;
	}
	:not(.head) > hr::before {
		content: "\2727\2003\2003\2727\2003\2003\2727";
	}

/******************************************************************************/
/*                            Paragraphs and Lists                            */
/******************************************************************************/

	p {
		margin: 1em 0;
	}

	dd > p:first-child,
	li > p:first-child {
		margin-top: 0;
	}

	ul, ol {
		margin-left: 0;
		padding-left: 2em;
	}

	li {
		margin: 0.25em 0 0.5em;
		padding: 0;
	}

	dl dd {
		margin: 0 0 .5em 2em;
	}

	.head dd + dd { /* compact for header */
		margin-top: -.5em;
	}

	/* Style for algorithms */
	ol.algorithm ol:not(.algorithm),
	.algorithm > ol ol:not(.algorithm) {
	border-left: 0.5em solid #DEF;
	border-left: 0.5em solid var(--algo-border);
	}

	/* Put nice boxes around each algorithm. */
	[data-algorithm]:not(.heading) {
	 padding: .5em;
	 border: thin solid #ddd;
	 border: thin solid var(--algo-border);
	 border-radius: .5em;
	 margin: .5em calc(-0.5em - 1px);
	}
	[data-algorithm]:not(.heading) > :first-child {
	 margin-top: 0;
	}
	[data-algorithm]:not(.heading) > :last-child {
	 margin-bottom: 0;
	}

	/* Style for switch/case <dl>s */
	dl.switch > dd > ol.only,
	dl.switch > dd > .only > ol {
	margin-left: 0;
	}
	dl.switch > dd > ol.algorithm,
	dl.switch > dd > .algorithm > ol {
	margin-left: -2em;
	}
	dl.switch {
	padding-left: 2em;
	}
	dl.switch > dt {
	text-indent: -1.5em;
	margin-top: 1em;
	}
	dl.switch > dt + dt {
	margin-top: 0;
	}
	dl.switch > dt::before {
	content: '\21AA';
	padding: 0 0.5em 0 0;
	display: inline-block;
	width: 1em;
	text-align: right;
	line-height: 0.5em;
	}

/** Terminology Markup ********************************************************/


/******************************************************************************/
/*                                 Inline Markup                              */
/******************************************************************************/

/** Terminology Markup ********************************************************/
	dfn   { /* Defining instance */
		font-weight: bolder;
	}
	a > i { /* Instance of term */
		font-style: normal;
	}
	dt dfn code, code.idl {
		font-size: inherit;
	}
	dfn var {
		font-style: normal;
	}

/** Change Marking ************************************************************/

	del {
		color: #aa0000;
		color: var(--del-text);
		background: transparent;
		background: var(--del-bg);
		text-decoration: line-through;
	}
	ins {
		color: #006100;
		color: var(--ins-text);
		background: transparent;
		background: var(--ins-bg);
		text-decoration: underline;
	}

	/* for amendments (candidate/proposed changes) */

	.amendment ins, .correction ins, .addition ins,
	ins[class^=c] {
		text-decoration-style: dotted;
	}
	.amendment del, .correction del, .addition del,
	del[class^=c] {
		text-decoration-style: dotted;
	}
	.amendment.proposed ins, .correction.proposed ins, .addition.proposed ins,
	ins[class^=c].proposed {
		text-decoration-style: double;
	}
	.amendment.proposed del, .correction.proposed del, .addition.proposed del,
	del[class^=c].proposed {
		text-decoration-style: double;
	}

/** Miscellaneous improvements to inline formatting ***************************/

	sup {
		vertical-align: super;
		font-size: 80%
	}

/******************************************************************************/
/*                                    Code                                    */
/******************************************************************************/

/** General monospace/pre rules ***********************************************/

	pre, code, samp {
		font-family: Menlo, Consolas, "DejaVu Sans Mono", Monaco, monospace;
		font-size: .9em;
		hyphens: none;
		text-transform: none;
		text-align: left;
		text-align: start;
		font-variant: normal;
		orphans: 3;
		widows: 3;
		page-break-before: avoid;
	}
	pre code,
	code code {
		font-size: 100%;
	}

	pre {
		margin-top: 1em;
		margin-bottom: 1em;
		overflow: auto;
	}

/** Inline Code fragments *****************************************************/

	/* Do something nice. */

/******************************************************************************/
/*                                    Links                                   */
/******************************************************************************/

/** General Hyperlinks ********************************************************/

	/* We hyperlink a lot, so make it less intrusive */
	a[href] {
		color: #034575;
		color: var(--a-normal-text);
		text-decoration: none;
		border-bottom: 1px solid #707070;
		border-bottom: 1px solid var(--a-normal-underline);
		/* Need a bit of extending for it to look okay */
		padding: 0 1px 0;
		margin: 0 -1px 0;
	}
	a:visited {
		color: #034575;
		color: var(--a-visited-text);
		border-bottom-color: #bbb;
		border-bottom-color: var(--a-visited-underline);
	}

	/* Use distinguishing colors when user is interacting with the link */
	a[href]:focus,
	a[href]:hover {
		background: #f8f8f8;
		background: rgba(75%, 75%, 75%, .25);
		background: var(--a-hover-bg);
		border-bottom-width: 3px;
		margin-bottom: -2px;
	}
	a[href]:active {
		color: #c00;
		color: var(--a-active-text);
		border-color: #c00;
		border-color: var(--a-active-underline);
	}

	/* Backout above styling for W3C logo */
	.head .logo,
	.head .logo a {
		border: none;
		text-decoration: none;
		background: transparent;
	}

/******************************************************************************/
/*                                    Images                                  */
/******************************************************************************/

	img {
		border-style: none;
	}

	img, svg {
		/* Intentionally not color-scheme aware. */
		background: white;
	}

	/* For autogen numbers, add
	  .caption::before, figcaption::before { content: "Figure " counter(figure) ". "; }
	*/

	figure, .figure, .sidefigure {
		page-break-inside: avoid;
		text-align: center;
		margin: 2.5em 0;
	}
	.figure img,	.sidefigure img,	figure img,
	.figure object, .sidefigure object, figure object {
		max-width: 100%;
		margin: auto;
		height: auto;
	}
	.figure pre, .sidefigure pre, figure pre {
		text-align: left;
		display: table;
		margin: 1em auto;
	}
	.figure table, figure table {
		margin: auto;
	}
	@media screen and (min-width: 20em) {
		.sidefigure {
			float: right;
			width: 50%;
			margin: 0 0 0.5em 0.5em;
		}
	}
	.caption, figcaption, caption {
		font-style: italic;
		font-size: 90%;
	}
	.caption::before, figcaption::before, figcaption > .marker {
		font-weight: bold;
	}
	.caption, figcaption {
		counter-increment: figure;
	}

	/* DL list is indented 2em, but figure inside it is not */
	dd > .figure, dd > figure { margin-left: -2em; }

/******************************************************************************/
/*                             Colored Boxes                                  */
/******************************************************************************/

	.issue, .note, .example, .assertion, .advisement, blockquote,
	.amendment, .correction, .addition {
		margin: 1em auto;
		padding: .5em;
		border: .5em;
		border-left-style: solid;
		page-break-inside: avoid;
	}
	span.issue, span.note {
		padding: .1em .5em .15em;
		border-right-style: solid;
	}

	blockquote > :first-child,
	.note  > p:first-child,
	.issue > p:first-child,
	.amendment > p:first-child,
	.correction > p:first-child,
	.addition > p:first-child {
		margin-top: 0;
	}
	blockquote > :last-child,
	.note  > p:last-child,
	.issue > p:last-child,
	.amendment > p:last-child,
	.correction > p:last-child,
	.addition > p:last-child {
		margin-bottom: 0;
	}


	.issue::before, .issue > .marker,
	.example::before, .example > .marker,
	.note::before, .note > .marker,
	details.note > summary > .marker,
	.amendment::before, .amendment > .marker,
	details.amendment > summary > .marker,
	.addition::before, .addition > .marker,
	addition.amendment > summary > .marker,
	.correction::before, .correction > .marker,
	correction.amendment > summary > .marker
	{
		text-transform: uppercase;
		padding-right: 1em;
	}

	.example::before, .example > .marker {
		display: block;
		padding-right: 0em;
	}

/** Blockquotes ***************************************************************/

	blockquote {
		border-color: silver;
		border-color: var(--blockquote-border);
		background: transparent;
		background: var(--blockquote-bg);
		color: currentcolor;
		color: var(--blockquote-text);
	}

/** Open issue ****************************************************************/

	.issue {
		border-color: #e05252;
		border-color: var(--issue-border);
		background: #fbe9e9;
		background: var(--issue-bg);
		color: black;
		color: var(--issue-text);
		counter-increment: issue;
		overflow: auto;
	}
	.issue::before, .issue > .marker {
		color: #831616;
		color: var(--issueheading-text);
	}
	/* Add .issue::before { content: "Issue " counter(issue) " "; } for autogen numbers,
	  or use class="marker" to mark up the issue number in source. */

/** Example *******************************************************************/

	.example {
		border-color: #e0cb52;
		border-color: var(--example-border);
		background: #fcfaee;
		background: var(--example-bg);
		color: black;
		color: var(--example-text);
		counter-increment: example;
		overflow: auto;
		clear: both;
	}
	.example::before, .example > .marker {
		color: #574b0f;
		color: var(--exampleheading-text);
	}
	/* Add .example::before { content: "Example " counter(example) " "; } for autogen numbers,
	  or use class="marker" to mark up the example number in source. */

/** Non-normative Note ********************************************************/

	.note {
		border-color: #52e052;
		border-color: var(--note-border);
		background: #e9fbe9;
		background: var(--note-bg);
		color: black;
		color: var(--note-text);
		overflow: auto;
	}

	.note::before, .note > .marker,
	details.note > summary {
		color: hsl(120, 70%, 30%);
		color: var(--noteheading-text);
	}
	/* Add .note::before { content: "Note "; } for autogen label,
	  or use class="marker" to mark up the label in source. */

	details.note[open] > summary {
		border-bottom: 1px silver solid;
		border-bottom: 1px var(--notesummary-underline) solid;
	}

/** Assertion Box *************************************************************/
	/*  for assertions in algorithms */

	.assertion {
		border-color: #AAA;
		border-color: var(--assertion-border);
		background: #EEE;
		background: var(--assertion-bg);
		color: black;
		color: var(--assertion-text);
	}

/** Advisement Box ************************************************************/
	/*  for attention-grabbing normative statements */

	.advisement {
		border-color: orange;
		border-color: var(--advisement-border);
		border-style: none solid;
		background: #fec;
		background: var(--advisement-bg);
		color: black;
		color: var(--advisement-text);
	}
	strong.advisement {
		display: block;
		text-align: center;
	}
	.advisement::before, .advisement > .marker {
		color: #b35f00;
		color: var(--advisementheading-text);
	}

/** Amendment Box *************************************************************/

	.amendment, .correction, .addition {
		border-color: #330099;
		border-color: var(--amendment-border);
		background: #F5F0FF;
		background: var(--amendment-bg);
		color: black;
		color: var(--amendment-text);
	}
	.amendment.proposed, .correction.proposed, .addition.proposed {
		border-style: solid;
		border-block-width: 0.25em;
	}
	.amendment::before, .amendment > .marker,
	details.amendment > summary::before, details.amendment > summary > .marker,
	.correction::before, .correction > .marker,
	details.correction > summary::before, details.correction > summary > .marker,
	.addition::before, .addition > .marker,
	details.addition > summary::before, details.addition > summary > .marker {
		color: #220066;
		color: var(--amendmentheading-text);
	}
	.amendment.proposed::before, .amendment.proposed > .marker,
	details.amendment.proposed > summary::before, details.amendment.proposed > summary > .marker,
	.correction.proposed::before, .correction.proposed > .marker,
	details.correction.proposed > summary::before, details.correction.proposed > summary > .marker,
	.addition.proposed::before, .addition.proposed > .marker,
	details.addition.proposed > summary::before, details.addition.proposed > summary > .marker {
		font-weight: bold;
	}

/** Spec Obsoletion Notice ****************************************************/
	/* obnoxious obsoletion notice for older/abandoned specs. */

	details {
		display: block;
	}
	summary {
		font-weight: bolder;
	}

	.annoying-warning:not(details),
	details.annoying-warning:not([open]) > summary,
	details.annoying-warning[open] {
		background: hsla(40,100%,50%,0.95);
		background: var(--warning-bg);
		color: black;
		color: var(--warning-text);
		padding: .75em 1em;
		border: red;
		border: var(--warning-border);
		border-style: solid none;
		box-shadow: 0 2px 8px black;
		text-align: center;
	}
	.annoying-warning :last-child {
		margin-bottom: 0;
	}

@media not print {
	details.annoying-warning[open] {
		position: fixed;
		left: 0;
		right: 0;
		bottom: 2em;
		z-index: 1000;
	}
}

	details.annoying-warning:not([open]) > summary {
		text-align: center;
	}

/** Entity Definition Boxes ***************************************************/

	.def {
		padding: .5em 1em;
		background: #def;
		background: var(--def-bg);
		margin: 1.2em 0;
		border-left: 0.5em solid #8ccbf2;
		border-left: 0.5em solid var(--def-border);
		color: black;
		color: var(--def-text);
	}

/******************************************************************************/
/*                                    Tables                                  */
/******************************************************************************/

	th, td {
		text-align: left;
		text-align: start;
	}

/** Property/Descriptor Definition Tables *************************************/

	table.def {
		/* inherits .def box styling, see above */
		width: 100%;
		border-spacing: 0;
	}

	table.def td,
	table.def th {
		padding: 0.5em;
		vertical-align: baseline;
		border-bottom: 1px solid #bbd7e9;
		border-bottom: 1px solid var(--defrow-border);
	}

	table.def > tbody > tr:last-child th,
	table.def > tbody > tr:last-child td {
		border-bottom: 0;
	}

	table.def th {
		font-style: italic;
		font-weight: normal;
		padding-left: 1em;
		width: 3em;
	}

	/* For when values are extra-complex and need formatting for readability */
	table td.pre {
		white-space: pre-wrap;
	}

	/* A footnote at the bottom of a def table */
	table.def td.footnote {
		padding-top: 0.6em;
	}
	table.def td.footnote::before {
		content: " ";
		display: block;
		height: 0.6em;
		width: 4em;
		border-top: thin solid;
	}

/** Data tables (and properly marked-up index tables) *************************/
	/*
		<table class="data"> highlights structural relationships in a table
		when correct markup is used (e.g. thead/tbody, th vs. td, scope attribute)

		Use class="complex data" for particularly complicated tables --
		(This will draw more lines: busier, but clearer.)

		Use class="long" on table cells with paragraph-like contents
		(This will adjust text alignment accordingly.)
		Alternately use class="longlastcol" on tables, to have the last column assume "long".
	*/

	table {
		word-wrap: normal;
		overflow-wrap: normal;
		hyphens: manual;
	}

	table.data,
	table.index {
		margin: 1em auto;
		border-collapse: collapse;
		border: hidden;
		width: 100%;
	}
	table.data caption,
	table.index caption {
		max-width: 50em;
		margin: 0 auto 1em;
	}

	table.data td,  table.data th,
	table.index td, table.index th {
		padding: 0.5em 1em;
		border-width: 1px;
		border-color: silver;
		border-color: var(--datacell-border);
		border-top-style: solid;
	}

	table.data thead td:empty {
		padding: 0;
		border: 0;
	}

	table.data  thead,
	table.index thead,
	table.data  tbody,
	table.index tbody {
		border-bottom: 2px solid;
	}

	table.data colgroup,
	table.index colgroup {
		border-left: 2px solid;
	}

	table.data  tbody th:first-child,
	table.index tbody th:first-child  {
		border-right: 2px solid;
		border-top: 1px solid silver;
		border-top: 1px solid var(--datacell-border);
		padding-right: 1em;
	}

	table.data th[colspan],
	table.data td[colspan] {
		text-align: center;
	}

	table.complex.data th,
	table.complex.data td {
		border: 1px solid silver;
		border: 1px solid var(--datacell-border);
		text-align: center;
	}

	table.data.longlastcol td:last-child,
	table.data td.long {
		vertical-align: baseline;
		text-align: left;
	}

	table.data img {
		vertical-align: middle;
	}


/*
Alternate table alignment rules

	table.data,
	table.index {
		text-align: center;
	}

	table.data  thead th[scope="row"],
	table.index thead th[scope="row"] {
		text-align: right;
	}

	table.data  tbody th:first-child,
	table.index tbody th:first-child  {
		text-align: right;
	}

Possible extra rowspan handling

	table.data  tbody th[rowspan]:not([rowspan='1']),
	table.index tbody th[rowspan]:not([rowspan='1']),
	table.data  tbody td[rowspan]:not([rowspan='1']),
	table.index tbody td[rowspan]:not([rowspan='1']) {
		border-left: 1px solid silver;
	}

	table.data  tbody th[rowspan]:first-child,
	table.index tbody th[rowspan]:first-child,
	table.data  tbody td[rowspan]:first-child,
	table.index tbody td[rowspan]:first-child{
		border-left: 0;
		border-right: 1px solid silver;
	}
*/

/******************************************************************************/
/*                                  Indices                                   */
/******************************************************************************/


/** Table of Contents *********************************************************/

	.toc a {
		/* More spacing; use padding to make it part of the click target. */
		padding-top: 0.1rem;
		/* Larger, more consistently-sized click target */
		display: block;
		/* Reverse color scheme */
		color: black;
		color: var(--toclink-text);
		border-color: #3980b5;
		border-color: var(--toclink-underline);
	}
	.toc a:visited {
		color: black;
		color: var(--toclink-visited-text);
		border-color: #054572;
		border-color: var(--toclink-visited-underline);
	}
	.toc a:not(:focus):not(:hover) {
		/* Allow colors to cascade through from link styling */
		border-bottom-color: transparent;
	}

	.toc, .toc ol, .toc ul, .toc li {
		list-style: none; /* Numbers must be inlined into source */
		/* because generated content isn't search/selectable and markers can't do multilevel yet */
		margin:  0;
		padding: 0;
	}
	.toc {
		line-height: 1.1em;
	}

	/* ToC not indented until third level, but font style & margins show hierarchy */
	.toc > li			{ font-weight: bold;   }
	.toc > li li		 { font-weight: normal; }
	.toc > li li li	  { font-size:   95%;	}
	.toc > li li li li	{ font-size:   90%;	}
	.toc > li li li li li { font-size:   85%;	}

	/* @supports not (display:grid) { */
		.toc > li			{ margin: 1.5rem 0;	}
		.toc > li li		 { margin: 0.3rem 0;	}
		.toc > li li li	  { margin-left: 2rem;   }

		/* Section numbers in a column of their own */
		.toc .secno {
			float: left;
			width: 4rem;
			white-space: nowrap;
		}
		.toc > li li li li .secno { font-size: 85%; }
		.toc > li li li li li .secno { font-size: 100%; }

		.toc li {
			clear: both;
		}

		:not(li) > .toc			 { margin-left:  5rem; }
		.toc .secno				 { margin-left: -5rem; }
		.toc > li li li .secno	  { margin-left: -7rem; }
		.toc > li li li li .secno	{ margin-left: -9rem; }
		.toc > li li li li li .secno { margin-left: -11rem; }

		/* Tighten up indentation in narrow ToCs */
		@media (max-width: 30em) {
			:not(li) > .toc			 { margin-left:  4rem; }
			.toc .secno				 { margin-left: -4rem; }
			.toc > li li li			 { margin-left:  1rem; }
			.toc > li li li .secno	  { margin-left: -5rem; }
			.toc > li li li li .secno	{ margin-left: -6rem; }
			.toc > li li li li li .secno { margin-left: -7rem; }
		}
		/* Loosen it on wide screens */
		@media screen and (min-width: 78em) {
			body:not(.toc-inline) :not(li) > .toc			 { margin-left:  4rem; }
			body:not(.toc-inline) .toc .secno				 { margin-left: -4rem; }
			body:not(.toc-inline) .toc > li li li			 { margin-left:  1rem; }
			body:not(.toc-inline) .toc > li li li .secno	  { margin-left: -5rem; }
			body:not(.toc-inline) .toc > li li li li .secno	{ margin-left: -6rem; }
			body:not(.toc-inline) .toc > li li li li li .secno { margin-left: -7rem; }
	}
	/* } */

	@supports (display:grid) and (display:contents) {
		/* Use #toc over .toc to override non-@supports rules. */
		#toc {
			display: grid;
			align-content: start;
			grid-template-columns: auto 1fr;
			grid-column-gap: 1rem;
			column-gap: 1rem;
			grid-row-gap: .6rem;
			row-gap: .6rem;
		}
		#toc h2 {
			grid-column: 1 / -1;
			margin-bottom: 0;
		}
		#toc ol,
		#toc li,
		#toc a {
			display: contents;
			/* Switch <a> to subgrid when supported */
		}
		#toc span {
			margin: 0;
		}
		#toc > .toc > li > a > span {
			/* The spans of the top-level list,
			  comprising the first items of each top-level section. */
			margin-top: 1.1rem;
		}
		#toc#toc .secno { /* Ugh, need more specificity to override base.css */
			grid-column: 1;
			width: auto;
			margin-left: 0;
		}
		#toc .content {
			grid-column: 2;
			width: auto;
			margin-right: 1rem;
		}
		#toc .content:hover,
		#toc .content:focus {
			background: rgba(75%, 75%, 75%, .25);
			background: var(--a-hover-bg);
			border-bottom: 3px solid #054572;
			border-bottom: 3px solid var(--toclink-underline);
			margin-bottom: -3px;
		}
		#toc li li li .content {
			margin-left: 1rem;
		}
		#toc li li li li .content {
			margin-left: 2rem;
		}
	}


/** Index *********************************************************************/

	/* Index Lists: Layout */
	ul.index	  { margin-left: 0; columns: 15em; text-indent: 1em hanging; }
	ul.index li	{ margin-left: 0; list-style: none; break-inside: avoid; }
	ul.index li li { margin-left: 1em; }
	ul.index dl	{ margin-top: 0; }
	ul.index dt	{ margin: .2em 0 .2em 20px;}
	ul.index dd	{ margin: .2em 0 .2em 40px;}
	/* Index Lists: Typography */
	ul.index ul,
	ul.index dl { font-size: smaller; }
	@media not print {
		ul.index li span:not(.dfn-paneled) {
			white-space: nowrap;
			color: transparent; }
		ul.index li a:hover + span,
		ul.index li a:focus + span {
			color: #707070;
			color: var(--indexinfo-text);
		}
	}

/** Index Tables *****************************************************/
	/* See also the data table styling section, which this effectively subclasses */

	table.index {
		font-size: small;
		border-collapse: collapse;
		border-spacing: 0;
		text-align: left;
		margin: 1em 0;
	}

	table.index td,
	table.index th {
		padding: 0.4em;
	}

	table.index tr:hover td:not([rowspan]),
	table.index tr:hover th:not([rowspan]) {
		color: black;
		color: var(--indextable-hover-text);
		background: #f7f8f9;
		background: var(--indextable-hover-bg);
	}

	/* The link in the first column in the property table (formerly a TD) */
	table.index th:first-child a {
		font-weight: bold;
	}

/** Outdated warning **********************************************************/

.outdated-spec {
	color: black;
	color: var(--outdatedspec-text);
	background-color: rgba(0,0,0,0.5);
	background-color: var(--outdatedspec-bg);
}

.outdated-warning {
	position: fixed;
	bottom: 50%;
	left: 0;
	right: 0;
	margin: 0 auto;
	width: 50%;
	background: maroon;
	background: var(--outdated-bg);
	color: white;
	color: var(--outdated-text);
	border-radius: 1em;
	box-shadow: 0 0 1em red;
	box-shadow: 0 0 1em var(--outdated-shadow);
	padding: 2em;
	text-align: center;
	z-index: 2;
}

.outdated-warning a {
	color: currentcolor;
	background: transparent;
}

.edited-rec-warning {
	background: darkorange;
	background: var(--editedrec-bg);
	box-shadow: 0 0 1em;
}

.outdated-warning button {
	color: var(--outdated-text);
	border-radius: 1em;
	box-shadow: 0 0 1em red;
	box-shadow: 0 0 1em var(--outdated-shadow);
	padding: 2em;
	text-align: center;
	z-index: 2;
}

.outdated-warning a {
	color: currentcolor;
	background: transparent;
}

.edited-rec-warning {
	background: darkorange;
	background: var(--editedrec-bg);
	box-shadow: 0 0 1em;
}

.outdated-warning button {
	position: absolute;
	top: 0;
	right:0;
	margin: 0;
	border: 0;
	padding: 0.25em 0.5em;
	background: transparent;
	color: white;
	color: var(--outdated-text);
	font:1em sans-serif;
	text-align:center;
}

.outdated-warning span {
	display: block;
}

.outdated-collapsed {
	bottom: 0;
	border-radius: 0;
	width: 100%;
	padding: 0;
}

/******************************************************************************/
/*                                    Print                                   */
/******************************************************************************/

	@media print {
		/* Pages have their own margins. */
		html {
			margin: 0;
		}
		/* Serif for print. */
		body {
			font-family: serif;
		}

		.outdated-warning {
			position: absolute;
			border-style: solid;
			border-color: red;
		}

		.outdated-warning input {
			display: none;
		}
	}
	@page {
		margin: 1.5cm 1.1cm;
	}



/******************************************************************************/
/*                             Overflow Control                               */
/******************************************************************************/

	.figure .caption, .sidefigure .caption, figcaption {
		/* in case figure is overlarge, limit caption to 50em */
		max-width: 50rem;
		margin-left: auto;
		margin-right: auto;
	}
	.overlarge {
		/* Magic to create good item positioning:
		  "content column" is 50ems wide at max; less on smaller screens.
		  Extra space (after ToC + content) is empty on the right.

		  1. When item < content column, centers item in column.
		  2. When content < item < available, left-aligns.
		  3. When item > available, fills available + scroll bar.
		*/
		display: grid;
		grid-template-columns: minmax(0, 50em);
	}
	.overlarge > table {
		/* limit preferred width of table */
		max-width: 50em;
		margin-left: auto;
		margin-right: auto;
	}

	@media (min-width: 55em) {
		.overlarge {
			margin-right: calc(13px + 26.5rem - 50vw);
			max-width: none;
		}
	}
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) .overlarge {
			/* 30.5em body padding 50em content area */
			margin-right: calc(40em - 50vw) !important;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) .overlarge {
			/* 4em html margin 30.5em body padding 50em content area */
			margin-right: calc(84.5em - 100vw) !important;
		}
	}

	@media not print {
		.overlarge {
			overflow-x: auto;
			/* See Lea Verou's explanation background-attachment:
			* http://lea.verou.me/2012/04/background-attachment-local/
			*
			background: top left  / 4em 100% linear-gradient(to right,  #ffffff, rgba(255, 255, 255, 0)) local,
						top right / 4em 100% linear-gradient(to left, #ffffff, rgba(255, 255, 255, 0)) local,
						top left  / 1em 100% linear-gradient(to right,  #c3c3c5, rgba(195, 195, 197, 0)) scroll,
						top right / 1em 100% linear-gradient(to left, #c3c3c5, rgba(195, 195, 197, 0)) scroll,
						white;
			background-repeat: no-repeat;
			*/
		}
	}
</style>
<style type="text/css">
    table, th, td {
      border: 1px solid black;
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    th, td {
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      padding: 0px 10px;
    }
    th {
      text-align: center;
    }

    del { background: #fcc; color: #000; text-decoration: line-through; }
    ins { background: #cfc; color: #000; }
    blockquote .highlight:not(.idl) { background: initial; margin: initial; padding: 0.5em }
    blockquote ul { background: inherit; }
    blockquote code.highlight:not(.idl) { padding: initial; }
    blockquote c-[a] { color: inherit; } /* Keyword.Declaration */
    blockquote c-[b] { color: inherit; } /* Keyword.Type */
    blockquote c-[c] { color: inherit; } /* Comment */
    blockquote c-[d] { color: inherit; } /* Comment.Multiline */
    blockquote c-[e] { color: inherit; } /* Name.Attribute */
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    blockquote c-[g] { color: inherit; } /* Name.Variable */
    blockquote c-[k] { color: inherit; } /* Keyword */
    blockquote c-[l] { color: inherit; } /* Literal */
    blockquote c-[m] { color: inherit; } /* Literal.Number */
    blockquote c-[n] { color: inherit; } /* Name */
    blockquote c-[o] { color: inherit; } /* Operator */
    blockquote c-[p] { color: inherit; } /* Punctuation */
    blockquote c-[s] { color: inherit; } /* Literal.String */
    blockquote c-[t] { color: inherit; } /* Literal.String.Single */
    blockquote c-[u] { color: inherit; } /* Literal.String.Double */
    blockquote c-[cp] { color: inherit; } /* Comment.Preproc */
    blockquote c-[c1] { color: inherit; } /* Comment.Single */
    blockquote c-[cs] { color: inherit; } /* Comment.Special */
    blockquote c-[kc] { color: inherit; } /* Keyword.Constant */
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    blockquote c-[py] { color: inherit; } /* Name.Property */
    blockquote c-[ow] { color: inherit; } /* Operator.Word */
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    blockquote c-[mh] { color: inherit; } /* Literal.Number.Hex */
    blockquote c-[mi] { color: inherit; } /* Literal.Number.Integer */
    blockquote c-[mo] { color: inherit; } /* Literal.Number.Oct */
    blockquote c-[sb] { color: inherit; } /* Literal.String.Backtick */
    blockquote c-[sc] { color: inherit; } /* Literal.String.Char */
    blockquote c-[sd] { color: inherit; } /* Literal.String.Doc */
    blockquote c-[se] { color: inherit; } /* Literal.String.Escape */
    blockquote c-[sh] { color: inherit; } /* Literal.String.Heredoc */
    blockquote c-[si] { color: inherit; } /* Literal.String.Interpol */
    blockquote c-[sx] { color: inherit; } /* Literal.String.Other */
    blockquote c-[sr] { color: inherit; } /* Literal.String.Regex */
    blockquote c-[ss] { color: inherit; } /* Literal.String.Symbol */
    blockquote c-[vc] { color: inherit; } /* Name.Variable.Class */
    blockquote c-[vg] { color: inherit; } /* Name.Variable.Global */
    blockquote c-[vi] { color: inherit; } /* Name.Variable.Instance */
    blockquote c-[il] { color: inherit; } /* Literal.Number.Integer.Long */
  </style>
  <meta content="Bikeshed version c5172e83, updated Fri Nov 20 15:35:20 2020 -0800" name="generator">
  <link href="https://wg21.link/P2474" rel="canonical">
  <link href="https://isocpp.org/favicon.ico" rel="icon">
<style>
pre {
  margin-top: 0px;
  margin-bottom: 0px;
}
table, th, tr, td {
  border: 2px solid black !important;
}
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  border: 2px solid white !important;
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 <body class="h-entry">
  <div class="head">
   <p data-fill-with="logo"></p>
   <h1 class="p-name no-ref" id="title">P2474R0<br><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code></h1>
   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Published Proposal, <time class="dt-updated" datetime="2021-12-13">2021-12-13</time></span></h2>
   <div data-fill-with="spec-metadata">
    <dl>
     <dt class="editor">Author:
     <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:griwes@griwes.info">Michał Dominiak</a>
     <dt>Project:
     <dd>ISO/IEC JTC1/SC22/WG21 14882: Programming Language — C++
     <dt>Audience:
     <dd>SG9, LEWG
    </dl>
   </div>
   <div data-fill-with="warning"></div>
   <hr title="Separator for header">
  </div>
  <nav data-fill-with="table-of-contents" id="toc">
   <h2 class="no-num no-toc no-ref" id="contents">Table of Contents</h2>
   <ol class="toc" role="directory">
    <li><a href="#intro"><span class="secno">1</span> <span class="content">Introduction</span></a>
    <li>
     <a href="#changes"><span class="secno">2</span> <span class="content">Changelog</span></a>
     <ol class="toc">
      <li><a href="#r0"><span class="secno">2.1</span> <span class="content">R0</span></a>
     </ol>
    <li><a href="#motivation"><span class="secno">3</span> <span class="content">Motivation</span></a>
    <li>
     <a href="#design"><span class="secno">4</span> <span class="content">Design</span></a>
     <ol class="toc">
      <li><a href="#repeat-view"><span class="secno">4.1</span> <span class="content"><code class="highlight"><c- n>repeat_view</c-></code></span></a>
      <li><a href="#repeat-cpo"><span class="secno">4.2</span> <span class="content"><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code></span></a>
      <li><a href="#move-borrowed"><span class="secno">4.3</span> <span class="content">Move-only types and borrowed range</span></a>
      <li><a href="#category"><span class="secno">4.4</span> <span class="content">Category</span></a>
      <li><a href="#properties"><span class="secno">4.5</span> <span class="content">Other properties</span></a>
      <li><a href="#take-drop"><span class="secno">4.6</span> <span class="content"><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code> changes</span></a>
     </ol>
    <li><a href="#experience"><span class="secno">5</span> <span class="content">Implementation experience</span></a>
    <li>
     <a href="#wording"><span class="secno">6</span> <span class="content">Wording</span></a>
     <ol class="toc">
      <li><a href="#wording-ranges"><span class="secno">6.1</span> <span class="content">Addition to <code class="highlight"><c- o>&lt;</c-><c- n>ranges</c-><c- o>></c-></code></span></a>
      <li>
       <a href="#wording-range.repeat"><span class="secno">6.2</span> <span class="content">Repeat view [range.repeat]</span></a>
       <ol class="toc">
        <li><a href="#wording-range.repeat.overview"><span class="secno">6.2.1</span> <span class="content">Overview [range.repeat.overview]</span></a>
        <li><a href="#wording-range.repeat.view"><span class="secno">6.2.2</span> <span class="content">Class template <code class="highlight"><c- n>repeat_view</c-></code> [range.repeat.view]</span></a>
        <li><a href="#wording-range.repeat.iterator"><span class="secno">6.2.3</span> <span class="content">Class template <code class="highlight"><c- n>repeat_view</c-><c- o>::</c-><c- n>iterator</c-></code> [range.repeat.iterator]</span></a>
       </ol>
      <li>
       <a href="#wording-range.take"><span class="secno">6.3</span> <span class="content">Take view [range.take]</span></a>
       <ol class="toc">
        <li><a href="#wording-range.take.overview"><span class="secno">6.3.1</span> <span class="content">Overview [range.take.overview]</span></a>
       </ol>
      <li>
       <a href="#wording-range.drop"><span class="secno">6.4</span> <span class="content">Drop view [range.drop]</span></a>
       <ol class="toc">
        <li><a href="#wording-range.drop.overview"><span class="secno">6.4.1</span> <span class="content">Overview [range.drop.overview]</span></a>
       </ol>
      <li><a href="#wording-ftm"><span class="secno">6.5</span> <span class="content">Feature-test macro</span></a>
     </ol>
    <li>
     <a href="#references"><span class="secno"></span> <span class="content">References</span></a>
     <ol class="toc">
      <li><a href="#informative"><span class="secno"></span> <span class="content">Informative References</span></a>
     </ol>
   </ol>
  </nav>
  <main>
   <h2 class="heading settled" data-level="1" id="intro"><span class="secno">1. </span><span class="content">Introduction</span><a class="self-link" href="#intro"></a></h2>
   <p>This paper proposes two new range factories:</p>
   <ol>
    <li data-md>
     <p><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code>, which is an infinite range that produces the same value repeatedly; and</p>
    <li data-md>
     <p><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat_n</c-></code>, which is a finite range of a specified size that produces the same value repeatedly.</p>
   </ol>
   <h2 class="heading settled" data-level="2" id="changes"><span class="secno">2. </span><span class="content">Changelog</span><a class="self-link" href="#changes"></a></h2>
   <h3 class="heading settled" data-level="2.1" id="r0"><span class="secno">2.1. </span><span class="content">R0</span><a class="self-link" href="#r0"></a></h3>
   <p>Initial revision.</p>
   <h2 class="heading settled" data-level="3" id="motivation"><span class="secno">3. </span><span class="content">Motivation</span><a class="self-link" href="#motivation"></a></h2>
   <p>// TODO</p>
   <h2 class="heading settled" data-level="4" id="design"><span class="secno">4. </span><span class="content">Design</span><a class="self-link" href="#design"></a></h2>
   <p>This paper proposes the following additions to the Ranges library:</p>
   <ol>
    <li data-md>
     <p>A new view type, <code class="highlight"><c- n>repeat_view</c-></code>, a view which repeatedly produces the same value, based on the design of <code class="highlight"><c- n>iota_view</c-></code>.</p>
    <li data-md>
     <p>A new customization point object, <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code>, which returns a <code class="highlight"><c- n>repeat_view</c-></code>, based on the design of <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>iota</c-></code>.</p>
    <li data-md>
     <p>An extension for the semantics of <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code>, to make them return bounded <code class="highlight"><c- n>repeat_view</c-></code> when passed a <code class="highlight"><c- n>repeat_view</c-></code>.</p>
   </ol>
   <p><a data-link-type="biblio" href="#biblio-p2214r1">[P2214R1]</a> suggests that <code class="highlight"><c- n>repeat</c-></code> and <code class="highlight"><c- n>repeat_n</c-></code> could be implemented in terms of <code class="highlight"><c- n>generate</c-></code> and <code class="highlight"><c- n>generate_n</c-></code>, however it also points out that the implementation of <code class="highlight"><c- n>generate</c-></code> in range-v3 contains a data race. To avoid this issue, this paper defines <code class="highlight"><c- n>repeat_view</c-></code> and <code class="highlight"><c- n>repeat_n_view</c-></code> similarly to how <code class="highlight"><c- n>iota_view</c-></code> is defined, which avoids the data race in <code class="highlight"><c- n>generate</c-></code>. (The data race manifests in the implementation of <code class="highlight"><c- n>generate</c-></code> filling its value cache inside a <code class="highlight"><c- k>const</c-></code> function. There’s a number of ways to resolve this issue, but the author would rather not make solving it a prerequisite for <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code>.)</p>
   <h3 class="heading settled" data-level="4.1" id="repeat-view"><span class="secno">4.1. </span><span class="content"><code class="highlight"><c- n>repeat_view</c-></code></span><a class="self-link" href="#repeat-view"></a></h3>
   <p><code class="highlight"><c- n>repeat_view</c-></code> is a class template that’s parametrized on the type of the value it produces, and an additional parameter which controls whether it is bounded or not. This view is a common range and a sized range when bounded. It is always a random access range.</p>
   <h3 class="heading settled" data-level="4.2" id="repeat-cpo"><span class="secno">4.2. </span><span class="content"><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code></span><a class="self-link" href="#repeat-cpo"></a></h3>
   <p><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code> is a customization point object which returns an unbounded <code class="highlight"><c- n>repeat_view</c-></code> when passed just a value, and a bounded <code class="highlight"><c- n>repeat_view</c-></code> when passed a value and a bound.</p>
   <h3 class="heading settled" data-level="4.3" id="move-borrowed"><span class="secno">4.3. </span><span class="content">Move-only types and borrowed range</span><a class="self-link" href="#move-borrowed"></a></h3>
   <p>Currently, there is no support for move-only types to be stored inside views; as is, this impacts <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>single</c-></code> (which requires the value type to be copyable), and the <code class="highlight"><c- n>transform_view</c-></code> family of adaptors (which requires the transform function to be copyable). The author proposes that this paper follow the requirements in the other adaptors, but also separately proposes to relax these requirements for both the existing adaptors and for the proposed <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code> in <a href="http://wg21.link/P2494R0">P2494</a>.</p>
   <p>This paper also proposes that iterators to <code class="highlight"><c- n>repeat_view</c-></code>s do not store copies of the values. There’s several reasons for this. For one, unlike the case of <code class="highlight"><c- n>iota_view</c-></code>, all the iterators to a <code class="highlight"><c- n>repeat_view</c-></code> always refer to the same value; copying the values all over to produce the same one from every iterator does not seem ideal. For another, if the iterators stored copies, the relaxation of the concept requirements mentioned above would not be possible. Finally, there is a precedent for this behavior: <code class="highlight"><c- n>repeat_view</c-></code> in Range-v3 does not copy the values into iterators, even though it still requires that the values be copyable.</p>
   <p>This, however, means that <code class="highlight"><c- n>repeat_view</c-></code> is <strong>not</strong> a borrowed range. This is a tradeoff, but the author believes that it is a worthy one.</p>
   <h3 class="heading settled" data-level="4.4" id="category"><span class="secno">4.4. </span><span class="content">Category</span><a class="self-link" href="#category"></a></h3>
   <p><code class="highlight"><c- n>repeat_view</c-></code> is always random access, because the variables being incremented while iterating are always integers or integer-like classes.</p>
   <h3 class="heading settled" data-level="4.5" id="properties"><span class="secno">4.5. </span><span class="content">Other properties</span><a class="self-link" href="#properties"></a></h3>
   <p><code class="highlight"><c- n>repeat_view</c-></code> is sized when a bound other than <code class="highlight"><c- n>unreachable_sentinel_t</c-></code> is provided.</p>
   <p><code class="highlight"><c- n>repeat_view</c-></code> is common when it is sized.</p>
   <h3 class="heading settled" data-level="4.6" id="take-drop"><span class="secno">4.6. </span><span class="content"><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code> changes</span><a class="self-link" href="#take-drop"></a></h3>
   <p><code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code> are specialized for a sized <code class="highlight"><c- n>iota_view</c-></code>, in which case they return an <code class="highlight"><c- n>iota_view</c-></code> back. They require that the <code class="highlight"><c- n>iota_view</c-></code> be sized, because the bound type for <code class="highlight"><c- n>iota_view</c-></code> can be an arbitrary type, so it is possible to have an <code class="highlight"><c- n>iota_view</c-></code> that is random access and finite, but for which there exists no way to obtain the size. In such a case, if we attempted to blindly increment the iterators by the value of the second argument of either <code class="highlight"><c- n>take</c-></code> or <code class="highlight"><c- n>drop</c-></code>, we could inadvertently reach an iterator that seems valid, but is in fact past the end of the range.</p>
   <p>For <code class="highlight"><c- n>repeat_view</c-></code>, this situation is much clearer: the value is never modified, and the bound is either <code class="highlight"><c- n>unreachable_sentinel_t</c-></code>, or an integer like type. In both cases we know that we can reuse the value, and set the bound to the appropriate value. Therefore, this paper proposes to extend the specializations of <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code> for <code class="highlight"><c- n>repeat_view</c-></code>, without requiring that it must be sized.</p>
   <h2 class="heading settled" data-level="5" id="experience"><span class="secno">5. </span><span class="content">Implementation experience</span><a class="self-link" href="#experience"></a></h2>
   <p>Range-v3 implements both the <a href="https://github.com/ericniebler/range-v3/blob/8dcb237d206069a1d70f40c0aee27e4b0de2b5fa/include/range/v3/view/repeat_n.hpp">bounded</a> and the <a href="https://github.com/ericniebler/range-v3/blob/8dcb237d206069a1d70f40c0aee27e4b0de2b5fa/include/range/v3/view/repeat.hpp">unbounded</a> variants of <code class="highlight"><c- n>repeat</c-></code>, but exposes them as separate functions and types. The author believes that this facility should instead follow the design of <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>iota</c-></code>. The two versions of <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code> in Range-v3 differ only by the existence of the size field in the view itself, by the existence of the <code class="highlight"><c- n>size</c-></code> function, and by the variant of the <code class="highlight"><c- n>view_facade</c-></code> base class they inherit from.</p>
   <h2 class="heading settled" data-level="6" id="wording"><span class="secno">6. </span><span class="content">Wording</span><a class="self-link" href="#wording"></a></h2>
   <h3 class="heading settled" data-level="6.1" id="wording-ranges"><span class="secno">6.1. </span><span class="content">Addition to <code class="highlight"><c- o>&lt;</c-><c- n>ranges</c-><c- o>></c-></code></span><a class="self-link" href="#wording-ranges"></a></h3>
   <p>Add the following to 24.2 [range.syn], Header <code class="highlight"><c- o>&lt;</c-><c- n>ranges</c-><c- o>></c-></code> synopsis:</p>
<pre class="highlight"><c- k>namespace</c-> <c- n>std</c-><c- o>::</c-><c- n>ranges</c-> <c- p>{</c->
  <c- c1>// ...</c->

  <c- k>namespace</c-> <c- n>views</c-> <c- p>{</c-> <c- kr>inline</c-> <c- k>constexpr</c-> <i><c- n>unspecified</c-></i> <c- n>iota</c-> <c- o>=</c-> <i><c- n>unspecified</c-></i><c- p>;</c-> <c- p>}</c->
<ins>
  <c- c1>// [range.repeat], repeat view</c->
  <c- k>template</c-><c- o>&lt;</c-><c- n>copy_constructible</c-> <c- n>W</c-><c- p>,</c-> <c- n>semiregular</c-> <c- n>Bound</c-> <c- o>=</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c->
  <c- k>class</c-> <c- nc>repeat_view</c-><c- p>;</c->

  <c- k>namespace</c-> <c- n>views</c-> <c- p>{</c-> <c- kr>inline</c-> <c- k>constexpr</c-> <i><c- n>unspecified</c-></i> <c- n>repeat</c-> <c- o>=</c-> <i><c- n>unspecified</c-></i><c- p>;</c-> <c- p>}</c->
</ins>
  <c- c1>// [range.istream], istream view</c->

  <c- c1>// ...</c->
<c- p>}</c->
</pre>
   <h3 class="heading settled" data-level="6.2" id="wording-range.repeat"><span class="secno">6.2. </span><span class="content">Repeat view [range.repeat]</span><a class="self-link" href="#wording-range.repeat"></a></h3>
   <p>Add a new section, Repeat view [range.repeat], after Iota view [range.iota].</p>
   <h4 class="heading settled" data-level="6.2.1" id="wording-range.repeat.overview"><span class="secno">6.2.1. </span><span class="content">Overview [range.repeat.overview]</span><a class="self-link" href="#wording-range.repeat.overview"></a></h4>
   <ol>
    <li data-md>
     <p><code class="highlight"><c- n>repeat_view</c-></code> generates a sequence of elements by repeatedly producing the same value.</p>
    <li data-md>
     <p>The name <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-></code> denotes a customization point object ([customization.point.object]). Given subexpressions <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code>, the expressions <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-></code> and <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>repeat</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code> are expression-equivalent to <code class="highlight"><c- n>repeat_view</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-></code> and <code class="highlight"><c- n>repeat_view</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code>, respectively.</p>
    <li data-md>
     <p>[ <i>Example:</i></p>
<pre class="language-c++ highlight">    <c- k>for</c-> <c- p>(</c-><c- b>int</c-> <c- nl>i</c-> <c- p>:</c-> <c- n>views</c-><c- o>::</c-><c- n>repeat</c-><c- p>(</c-><c- mi>17</c-><c- p>,</c-> <c- mi>4</c-><c- p>))</c->
      <c- n>cout</c-> <c- o>&lt;&lt;</c-> <c- n>i</c-> <c- o>&lt;&lt;</c-> <c- sc>' '</c-><c- p>;</c-> <c- c1>// prints: 17 17 17 17</c->
</pre>
     -- <i>end example</i> ] 
   </ol>
   <h4 class="heading settled" data-level="6.2.2" id="wording-range.repeat.view"><span class="secno">6.2.2. </span><span class="content">Class template <code class="highlight"><c- n>repeat_view</c-></code> [range.repeat.view]</span><a class="self-link" href="#wording-range.repeat.view"></a></h4>
<pre class="highlight"><c- k>namespace</c-> <c- n>std</c-><c- o>::</c-><c- n>ranges</c-> <c- p>{</c->
  <c- k>template</c-><c- o>&lt;</c-><c- n>copy_constructible</c-> <c- n>W</c-><c- p>,</c-> <c- n>semiregular</c-> <c- n>Bound</c-> <c- o>=</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c->
    <c- k>requires</c-> <i><c- n>is</c-><c- o>-</c-><c- n>integer</c-><c- o>-</c-><c- n>like</c-></i><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- o>||</c-> <c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c->
  <c- k>class</c-> <c- nc>repeat_view</c-> <c- o>:</c-> <c- k>public</c-> <c- n>view_interface</c-><c- o>&lt;</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Bound</c-><c- o>>></c-> <c- p>{</c->
  <c- k>private</c-><c- o>:</c->
    <c- c1>// [range.repeat.iterator], class range_view::iterator</c->
    <c- k>struct</c-> <i><c- n>iterator</c-></i><c- p>;</c->

    <i><c- n>movable</c-><c- o>-</c-><c- n>box</c-></i><c- o>&lt;</c-><c- n>W</c-><c- o>></c-> <c- n>value_</c-> <c- o>=</c-> <c- n>W</c-><c- p>();</c-> <c- c1>// exposition only, see [range.move.wrap]</c->
    <c- n>Bound</c-> <c- n>bound_</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>();</c-> <c- c1>// exposition only</c->

  <c- k>public</c-><c- o>:</c->
    <c- n>repeat_view</c-><c- p>()</c-> <c- k>requires</c-> <c- n>default_initializable</c-><c- o>&lt;</c-><c- n>W</c-><c- o>></c-> <c- o>=</c-> <c- k>default</c-><c- p>;</c->

    <c- k>template</c-><c- o>&lt;</c-><c- n>semiregular</c-> <c- n>Bnd</c-><c- o>></c->
    <c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- k>const</c-> <c- n>repeat_view</c-><c- o>&lt;</c-><c- n>V</c-><c- p>,</c-> <c- n>Bnd</c-><c- o>></c-> <c- o>&amp;</c-> <c- n>r</c-><c- p>,</c->
      <c- n>type_identity_t</c-><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
    <c- k>template</c-><c- o>&lt;</c-><c- n>semiregular</c-> <c- n>Bnd</c-><c- o>></c->
    <c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>V</c-><c- p>,</c-> <c- n>Bnd</c-><c- o>></c-> <c- o>&amp;&amp;</c-> <c- n>r</c-><c- p>,</c->
      <c- n>type_identity_t</c-><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
    <c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>repeat_view</c-><c- p>(</c-><c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- n>value</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
    <c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>repeat_view</c-><c- p>(</c-><c- n>W</c-> <c- o>&amp;&amp;</c-> <c- n>value</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
    <c- k>template</c-><c- o>&lt;</c-><c- n>class</c-><c- p>...</c-> <c- n>Args</c-><c- o>></c->
      <c- k>requires</c-> <c- n>constructible_from</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Args</c-><c- p>...</c-><c- o>></c->
    <c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>in_place_t</c-><c- p>,</c-> <c- n>Args</c-> <c- o>&amp;&amp;</c-><c- p>...</c-> <c- n>args</c-><c- p>);</c->
    <c- k>template</c-><c- o>&lt;</c-><c- n>class</c-><c- p>...</c-> <c- n>Args</c-><c- o>></c->
      <c- k>requires</c-> <c- n>constructible_from</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Args</c-><c- p>...</c-><c- o>></c->
    <c- k>constexpr</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>in_place_t</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-><c- p>,</c-> <c- n>Args</c-> <c- o>&amp;&amp;</c-><c- p>...</c-> <c- n>args</c-><c- p>);</c->

    <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- nf>begin</c-><c- p>()</c-> <c- k>const</c-><c- p>;</c->
    <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- nf>end</c-><c- p>()</c-> <c- k>const</c-> <c- k>requires</c-> <c- o>!</c-><c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c-><c- p>;</c->
    <c- k>constexpr</c-> <c- n>unreachable_sentinel_t</c-> <c- nf>end</c-><c- p>()</c-> <c- k>const</c-><c- p>;</c->

    <c- k>constexpr</c-> <c- k>auto</c-> <c- nf>size</c-><c- p>()</c-> <c- k>requires</c-> <c- o>!</c-><c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c-><c- p>;</c->
  <c- p>};</c->
<c- p>}</c->
</pre>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- n>semiregular</c-> <c- n>Bnd</c-><c- o>></c->
<c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- k>const</c-> <c- n>repeat_view</c-><c- o>&lt;</c-><c- n>V</c-><c- p>,</c-> <c- n>Bnd</c-><c- o>></c-> <c- o>&amp;</c-> <c- n>r</c-><c- p>,</c->
  <c- n>type_identity_t</c-><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
</pre>
   <ol>
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>r</c-><c- p>.</c-><c- n>value_</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>bound</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- n>semiregular</c-> <c- n>Bnd</c-><c- o>></c->
<c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>V</c-><c- p>,</c-> <c- n>Bnd</c-><c- o>></c-> <c- o>&amp;&amp;</c-> <c- n>r</c-><c- p>,</c->
  <c- n>type_identity_t</c-><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
</pre>
   <ol start="2">
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>move</c-><c- p>(</c-><c- n>r</c-><c- p>.</c-><c- n>value_</c-><c- p>)</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>bound</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>repeat_view</c-><c- p>(</c-><c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- n>value</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
</pre>
   <ol start="3">
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>value</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>bound</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>repeat_view</c-><c- p>(</c-><c- n>W</c-> <c- o>&amp;&amp;</c-> <c- n>value</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-> <c- o>=</c-> <c- n>Bound</c-><c- p>());</c->
</pre>
   <ol start="4">
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>move</c-><c- p>(</c-><c- n>value</c-><c- p>)</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>bound</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>typename</c-><c- p>...</c-> <c- n>Args</c-><c- o>></c->
  <c- k>requires</c-> <c- n>constructible_from</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Args</c-><c- p>...</c-><c- o>></c->
<c- k>constexpr</c-> <c- k>explicit</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>in_place_t</c-><c- p>,</c-> <c- n>Args</c-> <c- o>&amp;&amp;</c-><c- p>...</c-> <c- n>args</c-><c- p>);</c->
</pre>
   <ol start="5">
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>forward</c-><c- o>&lt;</c-><c- n>Args</c-><c- o>></c-><c- p>(</c-><c- n>args</c-><c- p>)...</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>typename</c-><c- p>...</c-> <c- n>Args</c-><c- o>></c->
  <c- k>requires</c-> <c- n>constructible_from</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Args</c-><c- p>...</c-><c- o>></c->
<c- k>constexpr</c-> <c- n>repeat_view</c-><c- p>(</c-><c- n>in_place_t</c-><c- p>,</c-> <c- n>Bound</c-> <c- n>bound</c-><c- p>,</c-> <c- n>Args</c-> <c- o>&amp;&amp;</c-><c- p>...</c-> <c- n>args</c-><c- p>);</c->
</pre>
   <ol start="6">
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>forward</c-><c- o>&lt;</c-><c- n>Args</c-><c- o>></c-><c- p>(</c-><c- n>args</c-><c- p>)...</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>bound</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- nf>begin</c-><c- p>()</c-> <c- k>const</c-><c- p>;</c->
</pre>
   <ol start="7">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>iterator</c-><c- p>{</c-><c- o>&amp;</c-><c- n>value_</c-><c- p>};</c-></code></p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- nf>end</c-><c- p>()</c-> <c- k>const</c-> <c- k>requires</c-> <c- o>!</c-><c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c-><c- p>;</c->
</pre>
   <ol start="8">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>iterator</c-><c- p>{</c-><c- o>&amp;</c-><c- n>value</c-><c- p>,</c-> <c- n>bound_</c-><c- p>};</c-></code></p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- n>unreachable_sentinel_t</c-> <c- nf>end</c-><c- p>()</c-> <c- k>const</c-><c- p>;</c->
</pre>
   <ol start="9">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>unreachable_sentinel</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- k>auto</c-> <c- nf>size</c-><c- p>()</c-> <c- k>requires</c-> <c- o>!</c-><c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c-><c- p>;</c->
</pre>
   <ol start="10">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>bound_</c-><c- p>;</c-></code></p>
   </ol>
   <h4 class="heading settled" data-level="6.2.3" id="wording-range.repeat.iterator"><span class="secno">6.2.3. </span><span class="content">Class template <code class="highlight"><c- n>repeat_view</c-><c- o>::</c-><c- n>iterator</c-></code> [range.repeat.iterator]</span><a class="self-link" href="#wording-range.repeat.iterator"></a></h4>
<pre class="highlight"><c- k>namespace</c-> <c- n>std</c-><c- o>::</c-><c- n>ranges</c-> <c- p>{</c->
  <c- k>template</c-><c- o>&lt;</c-><c- n>copyable</c-> <c- n>W</c-><c- p>,</c-> <c- n>semireular</c-> <c- n>Bound</c-> <c- o>=</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c->
    <c- k>requires</c-> <i><c- n>is</c-><c- o>-</c-><c- n>integer</c-><c- o>-</c-><c- n>like</c-></i><c- o>&lt;</c-><c- n>Bound</c-><c- o>></c-> <c- o>||</c-> <c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c->
  <c- k>class</c-> <c- nc>repeat_view</c-><c- o>&lt;</c-><c- n>W</c-><c- p>,</c-> <c- n>Bound</c-><c- o>>::</c-><i><c- n>iterator</c-></i> <c- p>{</c->
  <c- k>private</c-><c- o>:</c->
    <c- k>using</c-> <c- n>index_type</c-> <c- o>=</c-> <c- c1>// exposition only</c->
      <c- n>conditional_t</c-><c- o>&lt;</c-><c- n>same_as</c-><c- o>&lt;</c-><c- n>Bound</c-><c- p>,</c-> <c- n>unreachable_sentinel_t</c-><c- o>></c-><c- p>,</c->
        <c- b>ptrdiff_t</c-><c- p>,</c->
        <c- n>Bound</c->
      <c- o>></c-><c- p>;</c->
    <c- k>const</c-> <c- n>W</c-> <c- o>*</c-> <c- n>value_</c-><c- p>;</c-> <c- c1>// exposition only</c->
    <c- n>index_type</c-> <c- n>current_</c-> <c- o>=</c-> <c- n>index_type</c-><c- p>();</c-> <c- c1>// exposition only</c->

  <c- k>public</c-><c- o>:</c->
    <c- k>using</c-> <c- n>iterator_concept</c-> <c- o>=</c-> <c- n>random_access_iterator_tag</c-><c- p>;</c->
    <c- k>using</c-> <c- n>iterator_catetogy</c-> <c- o>=</c-> <c- n>random_access_iterator_tag</c-><c- p>;</c->
    <c- k>using</c-> <c- n>value_type</c-> <c- o>=</c-> <c- n>W</c-><c- p>;</c->
    <c- k>using</c-> <c- n>reference</c-> <c- o>=</c-> <c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-><c- p>;</c->
    <c- k>using</c-> <c- n>difference</c-> <c- o>=</c-> <i><c- n>see</c-> <c- n>below</c-></i><c- p>;</c->

    <i><c- n>iterator</c-></i><c- p>()</c-> <c- k>requires</c-> <c- n>default_initializable</c-><c- o>&lt;</c-><c- n>W</c-><c- o>></c-> <c- o>=</c-> <c- k>default</c-><c- p>;</c->

    <c- k>constexpr</c-> <c- k>explicit</c-> <i><c- nf>iterator</c-></i><c- p>(</c-><c- k>const</c-> <c- n>W</c-> <c- o>*</c-> <c- n>value</c-><c- p>,</c-> <c- n>index_type</c-> <c- n>b</c-> <c- o>=</c-> <c- n>index_type</c-><c- p>());</c->

    <c- k>constexpr</c-> <c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- k>operator</c-><c- o>*</c-><c- p>()</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->

    <c- k>constexpr</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- k>operator</c-><c- o>++</c-><c- p>();</c->
    <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- k>operator</c-><c- o>++</c-><c- p>(</c-><c- b>int</c-><c- p>);</c->

    <c- k>constexpr</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- k>operator</c-><c- o>--</c-><c- p>();</c->
    <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- k>operator</c-><c- o>--</c-><c- p>(</c-><c- b>int</c-><c- p>);</c->

    <c- k>constexpr</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- k>operator</c-><c- o>+=</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
    <c- k>constexpr</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- k>operator</c-><c- o>-=</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
    <c- k>constexpr</c-> <c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- k>operator</c-><c- p>[](</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->

    <c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>==</c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->

    <c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>&lt;</c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>></c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>&lt;=</c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>>=</c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <c- k>auto</c-> <c- k>operator</c-><c- o>&lt;=></c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->

    <c- k>friend</c-> <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- k>operator</c-><c- o>+</c-><c- p>(</c-><i><c- n>iterator</c-></i> <c- n>i</c-><c- p>,</c-> <c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- k>operator</c-><c- o>+</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>,</c-> <i><c- n>iterator</c-></i> <c- n>i</c-><c- p>);</c->

    <c- k>friend</c-> <c- k>constexpr</c-> <i><c- n>iterator</c-></i> <c- k>operator</c-><c- o>-</c-><c- p>(</c-><i><c- n>iterator</c-></i> <c- n>i</c-><c- p>,</c-> <c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
    <c- k>friend</c-> <c- k>constexpr</c-> <c- n>difference_type</c-> <c- k>operator</c-><c- o>-</c-><c- p>(</c-><c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <i><c- n>iterator</c-></i><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
  <c- p>};</c->
<c- p>}</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>iterator</c-><c- p>(</c-><c- k>const</c-> <c- n>W</c-> <c- o>*</c-> <c- n>value</c-><c- p>,</c-> <c- n>index_type</c-> <c- n>b</c-> <c- o>=</c-> <c- n>index_type</c-><c- p>());</c->
</pre>
   <ol>
    <li data-md>
     <p><em>Effects</em>: Initializes <code class="highlight"><c- n>value_</c-></code> with <code class="highlight"><c- n>value</c-></code> and <code class="highlight"><c- n>bound_</c-></code> with <code class="highlight"><c- n>b</c-></code>.</p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- k>operator</c-><c- o>*</c-><c- p>()</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
   <ol start="2">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- o>*</c-><c- n>value_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- k>operator</c-><c- o>++</c-><c- p>();</c->
</pre>
   <ol start="3">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- o>++</c-><c- n>current_</c-><c- p>;</c->
<c- k>return</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-> <c- k>operator</c-><c- o>++</c-><c- p>(</c-><c- b>int</c-><c- p>);</c->
</pre>
   <ol start="4">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- k>auto</c-> <c- n>tmp</c-> <c- o>=</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
<c- o>++*</c-><c- k>this</c-><c- p>;</c->
<c- k>return</c-> <c- n>tmp</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- k>operator</c-><c- o>--</c-><c- p>();</c->
</pre>
   <ol start="5">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- o>--</c-><c- n>current_</c-><c- p>;</c->
<c- k>return</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-> <c- k>operator</c-><c- o>--</c-><c- p>(</c-><c- b>int</c-><c- p>);</c->
</pre>
   <ol start="6">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- k>auto</c-> <c- n>tmp</c-> <c- o>=</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
<c- o>--*</c-><c- k>this</c-><c- p>;</c->
<c- k>return</c-> <c- n>tmp</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- k>operator</c-><c- o>+=</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
</pre>
   <ol start="7">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- n>current_</c-> <c- o>+=</c-> <c- n>n</c-><c- p>;</c->
<c- k>return</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- k>operator</c-><c- o>-=</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
</pre>
   <ol start="8">
    <li data-md>
     <p><em>Effects</em>: Equivalent to:</p>
   </ol>
<pre class="highlight"><c- n>current_</c-> <c- o>-=</c-> <c- n>n</c-><c- p>;</c->
<c- k>return</c-> <c- o>*</c-><c- k>this</c-><c- p>;</c->
</pre>
<pre class="highlight"><c- k>constexpr</c-> <c- k>const</c-> <c- n>W</c-> <c- o>&amp;</c-> <c- k>operator</c-><c- p>[](</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
   <ol start="9">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- o>*</c-><c- n>value_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>==</c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="10">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>==</c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>&lt;</c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="11">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>&lt;</c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>></c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="12">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>></c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>&lt;=</c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="13">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>&lt;=</c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- b>bool</c-> <c- k>operator</c-><c- o>>=</c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="14">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>>=</c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- k>auto</c-> <c- k>operator</c-><c- o>&lt;=></c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="15">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- n>x</c-><c- p>.</c-><c- n>current</c-> <c- o>&lt;=></c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- n>iterator</c-> <c- k>operator</c-><c- o>+</c-><c- p>(</c-><c- n>iterator</c-> <c- n>i</c-><c- p>,</c-> <c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
<c- k>friend</c-> <c- k>constexpr</c-> <c- n>iterator</c-> <c- k>operator</c-><c- o>+</c-><c- p>(</c-><c- n>difference_type</c-> <c- n>n</c-><c- p>,</c-> <c- n>iterator</c-> <c- n>i</c-><c- p>);</c->
</pre>
   <ol start="16">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>iterator</c-><c- p>{</c-><c- n>i</c-><c- p>.</c-><c- n>value_</c-><c- p>,</c-> <c- n>i</c-><c- p>.</c-><c- n>current_</c-> <c- o>+</c-> <c- n>n</c-><c- p>};</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- n>iterator</c-> <c- k>operator</c-><c- o>-</c-><c- p>(</c-><c- n>iterator</c-> <c- n>i</c-><c- p>,</c-> <c- n>difference_type</c-> <c- n>n</c-><c- p>);</c->
</pre>
   <ol start="17">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>iterator</c-><c- p>{</c-><c- n>i</c-><c- p>.</c-><c- n>value_</c-><c- p>,</c-> <c- n>i</c-><c- p>.</c-><c- n>current_</c-> <c- o>-</c-> <c- n>n</c-><c- p>};</c-></code></p>
   </ol>
<pre class="highlight"><c- k>friend</c-> <c- k>constexpr</c-> <c- n>difference_type</c-> <c- k>operator</c-><c- o>-</c-><c- p>(</c-><c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>x</c-><c- p>,</c-> <c- k>const</c-> <c- n>iterator</c-><c- o>&amp;</c-> <c- n>y</c-><c- p>);</c->
</pre>
   <ol start="18">
    <li data-md>
     <p><em>Effects</em>: Equivalent to <code class="highlight"><c- k>return</c-> <c- n>x</c-><c- p>.</c-><c- n>current_</c-> <c- o>-</c-> <c- n>y</c-><c- p>.</c-><c- n>current_</c-><c- p>;</c-></code></p>
   </ol>
   <h3 class="heading settled" data-level="6.3" id="wording-range.take"><span class="secno">6.3. </span><span class="content">Take view [range.take]</span><a class="self-link" href="#wording-range.take"></a></h3>
   <h4 class="heading settled" data-level="6.3.1" id="wording-range.take.overview"><span class="secno">6.3.1. </span><span class="content">Overview [range.take.overview]</span><a class="self-link" href="#wording-range.take.overview"></a></h4>
   <p>Modify Overview [range.take.overview] paragraph 2 as follows:</p>
   <p>2​. The name <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-></code> denotes a range adaptor object ([range.adaptor.object]).
Let <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code> be expressions, let <code class="highlight"><c- n>T</c-></code> be <code class="highlight"><c- n>remove_cvref_t</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>((</c-><c- n>E</c-><c- p>))</c-><c- o>></c-></code>, and let <code class="highlight"><c- n>D</c-></code> be <code class="highlight"><c- n>range_difference_t</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>((</c-><c- n>E</c-><c- p>))</c-><c- o>></c-></code>.
If <code class="highlight"><c- k>decltype</c-><c- p>((</c-><c- n>F</c-><c- p>))</c-></code> does not model <code class="highlight"><c- n>convertible_to</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-></code>, <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code> is ill-formed.
Otherwise, the expression <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>take</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code> is expression-equivalent to:</p>
   <ol>
    <li data-md>
     <p>If <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>empty_view</c-></code> ([range.empty.view]), then <code class="highlight"><c- p>((</c-><c- b>void</c-><c- p>)</c-> <c- n>F</c-><c- p>,</c-> <c- n>decay</c-><c- o>-</c-><c- n>copy</c-><c- p>(</c-><c- n>E</c-><c- p>))</c-></code>, except that the evaluations of <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code> are indeterminately sequenced.</p>
    <li data-md>
     <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> models <code class="highlight"><c- n>random_access_range</c-></code> and <code class="highlight"><c- n>sized_range</c-></code> and is a specialization of <code class="highlight"><c- n>span</c-></code> ([views.span]), <code class="highlight"><c- n>basic_string_view</c-></code> ([string.view]), or <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>subrange</c-></code> ([range.subrange]), then <code class="highlight"><c- n>U</c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>+</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>))</c-></code>, except that <code class="highlight"><c- n>E</c-></code> is evaluated only once, where <code class="highlight"><c- n>U</c-></code> is a type determined as follows:</p>
     <ol>
      <li data-md>
       <p>if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>span</c-></code>, then <code class="highlight"><c- n>U</c-></code> is <code class="highlight"><c- n>span</c-><c- o>&lt;</c-><c- k>typename</c-> <c- n>T</c-><c- o>::</c-><c- n>element_type</c-><c- o>></c-></code>;</p>
      <li data-md>
       <p>otherwise, if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>basic_string_view</c-></code>, then <code class="highlight"><c- n>U</c-></code> is <code class="highlight"><c- n>T</c-></code>;</p>
      <li data-md>
       <p>otherwise, <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>subrange</c-></code>, and <code class="highlight"><c- n>U</c-></code> is <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>subrange</c-><c- o>&lt;</c-><c- n>iterator_t</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>></c-></code>;</p>
     </ol>
    <li data-md>
     <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>iota_view</c-></code> ([range.iota.view]) that models <code class="highlight"><c- n>random_access_range</c-></code> and <code class="highlight"><c- n>sized_range</c-></code>, then <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>iota_view</c-><c- p>(</c-><c- o>*</c-><c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- o>*</c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>+</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>)))</c-></code>, except that <code class="highlight"><c- n>E</c-></code> is evaluated only once;</p>
   </ol>
   <ins>
    <ol start="4">
     <li data-md>
      <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>repeat_view</c-></code> ([range.repeat.view]):</p>
      <ol>
       <li data-md>
        <p>if <code class="highlight"><c- n>T</c-></code> models <code class="highlight"><c- n>sized_range</c-></code>, then <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>range_value_t</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-><c- p>,</c-> <c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>std</c-><c- o>::</c-><c- n>forward</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-><c- o>></c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>))</c-></code>, except that <code class="highlight"><c- n>E</c-></code> is evaluated only once;</p>
       <li data-md>
        <p>otherwise, <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>range_value_t</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-><c- p>,</c-> <c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code>;</p>
      </ol>
    </ol>
   </ins>
   <ol start="5">
    <li data-md>
     <p>Otherwise, <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>take_view</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code>.</p>
   </ol>
   <h3 class="heading settled" data-level="6.4" id="wording-range.drop"><span class="secno">6.4. </span><span class="content">Drop view [range.drop]</span><a class="self-link" href="#wording-range.drop"></a></h3>
   <h4 class="heading settled" data-level="6.4.1" id="wording-range.drop.overview"><span class="secno">6.4.1. </span><span class="content">Overview [range.drop.overview]</span><a class="self-link" href="#wording-range.drop.overview"></a></h4>
   <p>Modify Overview [range.drop.overview] paragraph 2 as follows:</p>
   <p>2​. The name <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-></code> denotes a range adaptor object ([range.adaptor.object]).
Let <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code> be expressions, let <code class="highlight"><c- n>T</c-></code> be <code class="highlight"><c- n>remove_cvref_t</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>((</c-><c- n>E</c-><c- p>))</c-><c- o>></c-></code>, and let <code class="highlight"><c- n>D</c-></code> be <code class="highlight"><c- n>range_difference_t</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>((</c-><c- n>E</c-><c- p>))</c-><c- o>></c-></code>.
If <code class="highlight"><c- k>decltype</c-><c- p>((</c-><c- n>F</c-><c- p>))</c-></code> does not model <code class="highlight"><c- n>convertible_to</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-></code>, <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code> is ill-formed.
Otherwise, the expression <code class="highlight"><c- n>views</c-><c- o>::</c-><c- n>drop</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code> is expression-equivalent to:</p>
   <ol>
    <li data-md>
     <p>If <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>empty_view</c-></code> ([range.empty.view]), then <code class="highlight"><c- p>((</c-><c- b>void</c-><c- p>)</c-> <c- n>F</c-><c- p>,</c-> <c- n>decay</c-><c- o>-</c-><c- n>copy</c-><c- p>(</c-><c- n>E</c-><c- p>))</c-></code>, except that the evaluations of <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code> are indeterminately sequenced.</p>
    <li data-md>
     <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> models <code class="highlight"><c- n>random_access_range</c-></code> and <code class="highlight"><c- n>sized_range</c-></code> and is</p>
     <ol>
      <li data-md>
       <p>a specialization of <code class="highlight"><c- n>span</c-></code> ([views.span]),</p>
      <li data-md>
       <p>a specialization of <code class="highlight"><c- n>basic_string_view</c-></code> ([string.view]),</p>
      <li data-md>
       <p>a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>iota_view</c-></code> ([range.iota.view]), or</p>
      <li data-md>
       <p>a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>subrange</c-></code> ([range.subrange]) where <code class="highlight"><c- n>T</c-><c- o>::</c-><c- n>StoreSize</c-></code> is <code class="highlight">false</code>,</p>
     </ol>
     <p>then <code class="highlight"><c- n>U</c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>+</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>),</c-> <c- n>ranges</c-><c- o>::</c-><c- n>end</c-><c- p>(</c-><c- n>E</c-><c- p>))</c-></code>, except that <code class="highlight"><c- n>E</c-></code> is evaluated only once, where <code class="highlight"><c- n>U</c-></code> is <code class="highlight"><c- n>span</c-><c- o>&lt;</c-><c- k>typename</c-> <c- n>T</c-><c- o>::</c-><c- n>element_type</c-><c- o>></c-></code> if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>span</c-></code> and <code class="highlight"><c- n>T</c-></code> otherwise.</p>
    <li data-md>
     <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>subrange</c-></code> ([range.subrange]) that models <code class="highlight"><c- n>random_access_range</c-></code> and <code class="highlight"><c- n>sized_range</c-></code>, then <code class="highlight"><c- n>T</c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>begin</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>+</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>),</c-> <c- n>ranges</c-><c- o>::</c-><c- n>end</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>to</c-><c- o>-</c-><c- b>unsigned</c-><c- o>-</c-><c- n>like</c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>-</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>)))</c-></code>, except that <code class="highlight"><c- n>E</c-></code> and <code class="highlight"><c- n>F</c-></code> are each evaluated only once.</p>
   </ol>
   <ins>
    <ol start="4">
     <li data-md>
      <p>Otherwise, if <code class="highlight"><c- n>T</c-></code> is a specialization of <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>repeat_view</c-></code> ([range.repeat.view]):</p>
      <ol>
       <li data-md>
        <p>if <code class="highlight"><c- n>T</c-></code> models <code class="highlight"><c- n>sized_range</c-></code>, then <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>repeat_view</c-><c- o>&lt;</c-><c- n>range_value_t</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-><c- p>,</c-> <c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>std</c-><c- o>::</c-><c- n>forward</c-><c- o>&lt;</c-><c- k>decltype</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-><c- o>></c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>)</c-> <c- o>-</c-> <c- n>std</c-><c- o>::</c-><c- n>min</c-><c- o>&lt;</c-><c- n>D</c-><c- o>></c-><c- p>(</c-><c- n>ranges</c-><c- o>::</c-><c- n>distance</c-><c- p>(</c-><c- n>E</c-><c- p>),</c-> <c- n>F</c-><c- p>))</c-></code>;</p>
       <li data-md>
        <p>otherwise, <code class="highlight"><c- n>E</c-></code>.</p>
      </ol>
    </ol>
   </ins>
   <ol start="4">
    <li data-md>
     <p>Otherwise, <code class="highlight"><c- n>ranges</c-><c- o>::</c-><c- n>drop_view</c-><c- p>(</c-><c- n>E</c-><c- p>,</c-> <c- n>F</c-><c- p>)</c-></code>.</p>
   </ol>
   <h3 class="heading settled" data-level="6.5" id="wording-ftm"><span class="secno">6.5. </span><span class="content">Feature-test macro</span><a class="self-link" href="#wording-ftm"></a></h3>
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  <h2 class="no-num no-ref heading settled" id="references"><span class="content">References</span><a class="self-link" href="#references"></a></h2>
  <h3 class="no-num no-ref heading settled" id="informative"><span class="content">Informative References</span><a class="self-link" href="#informative"></a></h3>
  <dl>
   <dt id="biblio-p2214r1">[P2214R1]
   <dd>Barry Revzin, Conor Hoekstra, Tim Song. <a href="https://wg21.link/p2214r1">A Plan for C++23 Ranges</a>. 14 September 2021. URL: <a href="https://wg21.link/p2214r1">https://wg21.link/p2214r1</a>
  </dl>