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<!DOCTYPE html>
<html class="split chapter"><head><meta charset="utf-8"><title>14 Program # Ⓣ Ⓔ ① Ⓐ — Annotated ES5</title><link rel="stylesheet" href="style.css"><link href="x13.html" title="13 Function Definition " rel="prev">
<link href="spec.html" title="TOC" rel="index">
<link href="x15.html" title="15 Standard Built-in ECMAScript Objects " rel="next">
</head><body><div class="head">
<h2 id="top">Annotated ECMAScript 5.1 <span id="timestamp"></span></h2>
<div id="mascot-treehouse">
<img id="mascot" align="left" src="js-mascot.svg" alt=""><img id="bubble" src="bubble.svg" alt=""></div>
<p id="slogan">‟Ex igne vita”</p>
<div id="annotations"></div>
<script src="timestamp.js"></script></div>
<nav>
<a href="x13.html">← 13 Function Definition </a> –
<a href="spec.html" class="toc-nav">TOC</a> –
<a href="x15.html">15 Standard Built-in ECMAScript Objects →</a>
<ol class="toc"><li><a href="x14.html#x14" id="x14-toc">14 Program</a>
<b class="erra">Ⓔ</b> <b class="rev1">①</b> <b class="anno">Ⓐ</b> <ol><li><a href="x14.html#x14.1" id="x14.1-toc">14.1 Directive Prologues and the Use Strict Directive</a> <b class="erra">Ⓔ</b> <b class="rev1">①</b> <b class="anno">Ⓐ</b> </li></ol></li></ol></nav>
<h2 id="x14">14 Program <a href="#x14">#</a> <a href="#x14-toc" class="bak">Ⓣ</a> <b class="erra">Ⓔ</b> <b class="rev1">①</b> <b class="anno">Ⓐ</b></h2>
<p class="tiny-btm">
<b>Syntax</b></p>
<p class="keep">
<i>Program </i><b>:</b></p>
<p class="def1-btm">
<i>SourceElements</i><sub>opt</sub></p>
<p class="keep">
<i>SourceElements </i><b>:</b></p>
<p class="def1-btm">
<i>SourceElement<br>SourceElements
SourceElement</i></p>
<p class="keep">
<i>SourceElement </i><b>:</b></p>
<p class="def1-btm">
<i><a href="x12.html#x12">Statement</a><br><a href="x13.html#x13">FunctionDeclaration</a></i></p>
<p class="tiny-btm">
<b>Semantics</b></p>
<p>
The
production <i>Program </i><b>:</b><i>SourceElements</i><sub>opt</sub><code>
</code>is evaluated as follows:</p>
<ol><li><p>
The
code of this <i>Program</i> is <a href="x10.html#x10.1.1" class="term-ref">strict mode code</a> if the Directive
Prologue (<a href="#x14.1">14.1</a>) of its <i>SourceElements</i> contains a Use Strict
Directive or if any of the conditions of <a href="x10.html#x10.1.1">10.1.1</a> apply. If the code
of this <i>Program</i> is <a href="x10.html#x10.1.1" class="term-ref">strict mode code</a>, <i>SourceElements</i>
is evaluated in the following steps as <a href="x10.html#x10.1.1" class="term-ref">strict mode code</a>. Otherwise
<i>SourceElements</i> is evaluated in the following steps as
non-<a href="x10.html#x10.1.1" class="term-ref">strict mode code</a>.</p>
</li>
<li><p>
If
<i>SourceElements</i> is not present, return (normal,
empty, empty).</p>
</li>
<li><p>
Let
<i>progCxt</i> be a new execution context for <a href="x10.html#global-code">global code</a> as
described in <a href="x10.html#x10.4.1">10.4.1</a>.
</p>
</li>
<li><p>
Let
<i>result </i>be the result of evaluating <i>SourceElements</i>.</p>
</li>
<li><p>
Exit
the execution context <i>progCxt</i>.</p>
</li>
<li><p>
Return
<i>result</i>.</p>
</li></ol><p><b class="note">NOTE</b> The
processes for initiating the evaluation of a <i>Program</i>
and for dealing with the result of such an evaluation are defined by
an ECMAScript implementation and not by this specification.</p>
<p>
The
production <i>SourceElements</i>
<b>:</b> <i>SourceElements</i>
<i>SourceElement</i> is
evaluated as follows:</p>
<ol><li><p>
Let
<i>headResult</i> be the result of evaluating <i>SourceElements</i>.</p>
</li>
<li><p>
If
<i>headResult</i> is an <a href="x8.html#x8.9">abrupt completion</a>, return <i>headResult</i></p>
</li>
<li><p>
Let
<i>tailResult</i> be result of evaluating <i>SourceElement</i>.</p>
</li>
<li><p>
If
<i>tailResult</i>.value is empty,
let <i>V</i> = <i>headResult</i>.value, otherwise let <i>V</i> =
<i>tailResult</i>.value.</p>
</li>
<li><p>
Return
(tailResult.type, V, tailResult.target)
</p>
</li></ol><p>
The
production <i>SourceElement </i><b>:</b><i>Statement </i>is evaluated as follows:</p>
<ol><li><p>
Return
the result of evaluating <i><a href="x12.html#x12">Statement</a></i>.</p>
</li></ol><p>
The
production <i>SourceElement </i><b>:</b><i><a href="x13.html#x13">FunctionDeclaration</a></i> is evaluated as follows:</p>
<ol><li><p>
Return
(normal, empty,
empty).</p>
</li></ol><h3 id="x14.1">14.1 Directive Prologues and the Use Strict Directive <a href="#x14.1">#</a> <a href="#x14.1-toc" class="bak">Ⓣ</a> <b class="erra">Ⓔ</b> <b class="rev1">①</b> <b class="anno">Ⓐ</b></h3>
<p>
A
Directive Prologue is the longest sequence of <i>ExpressionStatement </i>productions occurring as the initial <i>SourceElement</i>
productions of a <i><a href="#x14">Program</a></i>
or <i><a href="x13.html#x13">FunctionBody</a></i>
and where each <i>ExpressionStatement </i>in the sequence
consists entirely of a <i>StringLiteral</i>
token followed a semicolon.
The semicolon may appear explicitly or may be inserted by
<a href="x7.html#x7.9">automatic semicolon insertion</a>. A Directive Prologue may be an empty sequence.</p>
<p>
A Use
Strict Directive is an <i>ExpressionStatement</i>
in a Directive Prologue whose <i>StringLiteral</i>
is either the exact character sequences <code><b>"use</b></code><code> </code><code><b>strict"</b></code>
or<code><b> 'use</b></code><code> </code><code><b>strict'</b></code>.
A Use Strict Directive may not contain an <i>EscapeSequence</i>
or <i>LineContinuation</i>.</p>
<p>
A
Directive Prologue may contain more than one Use Strict Directive.
However, an implementation may issue a warning if this occurs.</p>
<p><b class="note">NOTE</b> The
<i>ExpressionStatement</i>
productions of a Directive Prologue are evaluated normally during
evaluation of the containing <i>SourceElements</i>
production. Implementations may define implementation specific
meanings for <i>ExpressionStatement</i>
productions which are not a Use Strict Directive and which occur in
a Directive Prologue. If an appropriate notification mechanism
exists, an implementation should issue a warning if it encounters in
a Directive Prologue an <i>ExpressionStatement</i>
that is not a Use Strict Directive or which does not have a meaning
defined by the implementation.</p>
</body><script src="anno.js"></script></html>