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Editorial: Copy EscapeSequence to TemplateEscapeSequence (tc39#1867)
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... and replace the former with the latter in TemplateCharacter.

The spec prohibits applying the B.1.2 extensions
to EscapeSequence when it appears in TemplateCharacter;
this change accomplishes that in the grammar rather than in prose.

(This makes it a little easier to 'mainline' the B.1.2 extensions
in the next commit.)
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@jmdyck @mathiasbynens
jmdyck authored and mathiasbynens committed Oct 18, 2021
1 parent 9dbd7f2 commit da0beea
Showing 1 changed file with 17 additions and 8 deletions.
25 changes: 17 additions & 8 deletions spec.html
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Original file line number Diff line number Diff line change
Expand Up @@ -16874,6 +16874,9 @@ <h1>Static Semantics: SV</h1>
<li>
The SV of <emu-grammar>UnicodeEscapeSequence :: `u{` CodePoint `}`</emu-grammar> is the result of performing UTF16EncodeCodePoint on the MV of |CodePoint|.
</li>
<li>
The SV of <emu-grammar>TemplateEscapeSequence :: `0`</emu-grammar> is the String value consisting of the code unit 0x0000 (NULL).
</li>
</ul>
</emu-clause>

Expand Down Expand Up @@ -17000,12 +17003,18 @@ <h2>Syntax</h2>

TemplateCharacter ::
`$` [lookahead != `{`]
`\` EscapeSequence
`\` TemplateEscapeSequence
`\` NotEscapeSequence
LineContinuation
LineTerminatorSequence
SourceCharacter but not one of ``` or `\` or `$` or LineTerminator

TemplateEscapeSequence ::
CharacterEscapeSequence
`0` [lookahead &notin; DecimalDigit]
HexEscapeSequence
UnicodeEscapeSequence

NotEscapeSequence ::
`0` DecimalDigit
DecimalDigit but not `0`
Expand All @@ -17025,7 +17034,6 @@ <h2>Syntax</h2>
CodePoint ::
HexDigits[~Sep] [> but only if MV of |HexDigits| &le; 0x10FFFF]
</emu-grammar>
<p>A conforming implementation must not use the extended definition of |EscapeSequence| described in <emu-xref href="#sec-additional-syntax-string-literals"></emu-xref> when parsing a |TemplateCharacter|.</p>
<emu-note>
<p>|TemplateSubstitutionTail| is used by the |InputElementTemplateTail| alternative lexical goal.</p>
</emu-note>
Expand Down Expand Up @@ -17056,7 +17064,7 @@ <h1>Static Semantics: TV</h1>
The TV of <emu-grammar>TemplateCharacter :: `$`</emu-grammar> is the String value consisting of the code unit 0x0024 (DOLLAR SIGN).
</li>
<li>
The TV of <emu-grammar>TemplateCharacter :: `\` EscapeSequence</emu-grammar> is the SV of |EscapeSequence|.
The TV of <emu-grammar>TemplateCharacter :: `\` TemplateEscapeSequence</emu-grammar> is the SV of |TemplateEscapeSequence|.
</li>
<li>
The TV of <emu-grammar>TemplateCharacter :: `\` NotEscapeSequence</emu-grammar> is *undefined*.
Expand Down Expand Up @@ -17096,13 +17104,13 @@ <h1>Static Semantics: TRV</h1>
The TRV of <emu-grammar>TemplateCharacter :: `$`</emu-grammar> is the String value consisting of the code unit 0x0024 (DOLLAR SIGN).
</li>
<li>
The TRV of <emu-grammar>TemplateCharacter :: `\` EscapeSequence</emu-grammar> is the string-concatenation of the code unit 0x005C (REVERSE SOLIDUS) and the TRV of |EscapeSequence|.
The TRV of <emu-grammar>TemplateCharacter :: `\` TemplateEscapeSequence</emu-grammar> is the string-concatenation of the code unit 0x005C (REVERSE SOLIDUS) and the TRV of |TemplateEscapeSequence|.
</li>
<li>
The TRV of <emu-grammar>TemplateCharacter :: `\` NotEscapeSequence</emu-grammar> is the string-concatenation of the code unit 0x005C (REVERSE SOLIDUS) and the TRV of |NotEscapeSequence|.
</li>
<li>
The TRV of <emu-grammar>EscapeSequence :: `0`</emu-grammar> is the String value consisting of the code unit 0x0030 (DIGIT ZERO).
The TRV of <emu-grammar>TemplateEscapeSequence :: `0`</emu-grammar> is the String value consisting of the code unit 0x0030 (DIGIT ZERO).
</li>
<li>
The TRV of <emu-grammar>NotEscapeSequence :: `0` DecimalDigit</emu-grammar> is the string-concatenation of the code unit 0x0030 (DIGIT ZERO) and the TRV of |DecimalDigit|.
Expand Down Expand Up @@ -17181,7 +17189,7 @@ <h1>Static Semantics: TRV</h1>
</li>
</ul>
<emu-note>
<p>TV excludes the code units of |LineContinuation| while TRV includes them. &lt;CR&gt;&lt;LF&gt; and &lt;CR&gt; |LineTerminatorSequence|s are normalized to &lt;LF&gt; for both TV and TRV. An explicit |EscapeSequence| is needed to include a &lt;CR&gt; or &lt;CR&gt;&lt;LF&gt; sequence.</p>
<p>TV excludes the code units of |LineContinuation| while TRV includes them. &lt;CR&gt;&lt;LF&gt; and &lt;CR&gt; |LineTerminatorSequence|s are normalized to &lt;LF&gt; for both TV and TRV. An explicit |TemplateEscapeSequence| is needed to include a &lt;CR&gt; or &lt;CR&gt;&lt;LF&gt; sequence.</p>
</emu-note>
</emu-clause>
</emu-clause>
Expand Down Expand Up @@ -27092,7 +27100,7 @@ <h1>Forbidden Extensions</h1>
When processing strict mode code, an implementation must not relax the early error rules of <emu-xref href="#sec-numeric-literals-early-errors"></emu-xref>.
</li>
<li>
|TemplateCharacter| must not be extended to include <emu-xref href="#prod-annexB-LegacyOctalEscapeSequence"></emu-xref> or <emu-xref href="#prod-annexB-NonOctalDecimalEscapeSequence"></emu-xref> as defined in <emu-xref href="#sec-additional-syntax-string-literals"></emu-xref>.
|TemplateEscapeSequence| must not be extended to include <emu-xref href="#prod-annexB-LegacyOctalEscapeSequence"></emu-xref> or <emu-xref href="#prod-annexB-NonOctalDecimalEscapeSequence"></emu-xref> as defined in <emu-xref href="#sec-additional-syntax-string-literals"></emu-xref>.
</li>
<li>
When processing strict mode code, the extensions defined in <emu-xref href="#sec-labelled-function-declarations"></emu-xref>, <emu-xref href="#sec-block-level-function-declarations-web-legacy-compatibility-semantics"></emu-xref>, <emu-xref href="#sec-functiondeclarations-in-ifstatement-statement-clauses"></emu-xref>, and <emu-xref href="#sec-initializers-in-forin-statement-heads"></emu-xref> must not be supported.
Expand Down Expand Up @@ -45070,6 +45078,7 @@ <h1>Lexical Grammar</h1>
<emu-prodref name="TemplateTail"></emu-prodref>
<emu-prodref name="TemplateCharacters"></emu-prodref>
<emu-prodref name="TemplateCharacter"></emu-prodref>
<emu-prodref name="TemplateEscapeSequence"></emu-prodref>
<emu-prodref name="NotEscapeSequence"></emu-prodref>
<emu-prodref name="NotCodePoint"></emu-prodref>
<emu-prodref name="CodePoint"></emu-prodref>
Expand Down Expand Up @@ -45421,7 +45430,7 @@ <h2>Syntax</h2>
NonOctalDecimalEscapeSequence :: one of
`8` `9`
</emu-grammar>
<p>This definition of |EscapeSequence| is not used in strict mode or when parsing |TemplateCharacter|.</p>
<p>This definition of |EscapeSequence| is not used in strict mode.</p>
<emu-note>
<p>It is possible for string literals to precede a Use Strict Directive that places the enclosing code in <emu-xref href="#sec-strict-mode-code">strict mode</emu-xref>, and implementations must take care to not use this extended definition of |EscapeSequence| with such literals. For example, attempting to parse the following source text must fail:</p>
<pre><code class="javascript">
Expand Down

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