fixup: review feedback

spec.emu

@@ -27,35 +27,54 @@ contributors: Jordan Harband
         <emu-alg>
           1. Let _str_ be ? ToString(_S_).
           1. Let _cpList_ be StringToCodePoints(_str_).
-          1. Let _punctuators_ be the following String, which consists of every ASCII punctuator except U+005F (LOW LINE): *"(){}[]|,.?\*+-^$=<>\/#&!%:;@~'"`"*.
-          1. Let _toEscape_ be StringToCodePoints(_punctuators_).
           1. Let _escapedList_ be a new empty List.
           1. For each code point _c_ in _cpList_, do
             1. If _escapedList_ is empty and _c_ is matched by |DecimalDigit|, then
               1. Append code unit U+005C (REVERSE SOLIDUS) to _escapedList_.
               1. Append code unit U+0078 (LATIN SMALL LETTER X) to _escapedList_.
               1. Append code unit U+0033 (DIGIT THREE) to _escapedList_.
               1. Append _c_ to _escapedList_.
-            1. Else if _toEscape_ contains _c_ or _c_ is matched by |WhiteSpace|, then
-              1. Let _hex_ be Number::toString(𝔽(_c_), 16).
-              1. If the length of _hex_ is 1 or 2, then
-                1. Set _hex_ to StringPad(_hex_, 2, *"0"*, ~start~).
-                1. Append code unit U+0078 (LATIN SMALL LETTER X) to _escapedList_.
-                1. Append the code units in _hex_ to _escapedList_.
-              1. Else,
-                1. Assert: The length of _hex_ is at most 4.
-                1. Set _hex_ to StringPad(_hex_, 4, *"0"*, ~start~).
-                1. Append code unit U+0075 (LATIN SMALL LETTER U) to _escapedList_.
-                1. Append the code units in _hex_ to _escapedList_.
             1. Else,
-              1. Append _c_ to _escapedList_.
+              1. Append the code units in EncodeForRegExpEscape(_c_) to _escapedList_.
           1. Return CodePointsToString(_escapedList_).
         </emu-alg>
 
         <emu-note>
           <p>`escape` takes a string and escapes it so it can be literally represented as a pattern. In contrast EscapeRegExpPattern (as the name implies) takes a pattern and escapes it so that it can be represented as a string. While the two are related, they do not share the same character escape set or perform similar actions.</p>
         </emu-note>
       </emu-clause>
+
+      <emu-clause id="sec-encode" type="abstract operation">
+        <h1>
+          EncodeForRegExpEscape (
+            _c_: a code unit,
+          ): a List of code units
+        </h1>
+        <dl class="header">
+          <dt>description</dt>
+          <dd>If the code unit represents a RegExp punctuator that needs escaping, or ASCII whitespace, it produces the code units for *"\x"* followed by the relevant escape code. If the code unit represents non-ASCII white space, it produces the code units for *"\u"* followed by the relevant escape code. Otherwise, it returns a List containing the original code unit.</dd>
+        </dl>
+
+        <emu-alg>
+          1. Let _codeUnits_ be a new empty List.
+          1. Let _punctuators_ be the following String, which consists of every ASCII punctuator except U+005F (LOW LINE): *"(){}[]|,.?\*+-^$=<>\/#&!%:;@~'"`"*.
+          1. Let _toEscape_ be StringToCodePoints(_punctuators_).
+          1. If _toEscape_ contains _c_ or _c_ is matched by |WhiteSpace|, then
+            1. Append code unit U+005C (REVERSE SOLIDUS) to _codeUnits_.
+            1. Let _hex_ be Number::toString(𝔽(_c_), 16).
+            1. If the length of _hex_ is 1 or 2, then
+              1. Set _hex_ to StringPad(_hex_, 2, *"0"*, ~start~).
+              1. Append code unit U+0078 (LATIN SMALL LETTER X) to _codeUnits_.
+            1. Else,
+              1. Assert: The length of _hex_ is at most 4.
+              1. Set _hex_ to StringPad(_hex_, 4, *"0"*, ~start~).
+              1. Append code unit U+0075 (LATIN SMALL LETTER U) to _codeUnits_.
+            1. Append the code units in _hex_ to _codeUnits_.
+          1. Else,
+            1. Append _c_ to _codeUnits_.
+          1. Return _codeUnits_.
+        </emu-alg>
+      </emu-clause>
       </ins>
     </emu-clause>
   </emu-clause>