Editorial: Parameterize UTCOffset grammar

Instead of two separate productions UTCOffsetSubMinutePrecision and UTCOffsetMinutePrecision, we can have one UTCOffset production with a SubMinutePrecision parameter.
tc39 · Jun 13, 2024 · c3eb4cf · c3eb4cf
1 parent 3d53cf6
commit c3eb4cf
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Showing 4 changed files with 29 additions and 30 deletions.
diff --git a/polyfill/test/validStrings.mjs b/polyfill/test/validStrings.mjs
@@ -245,23 +245,28 @@ const timeFraction = withCode(temporalDecimalFraction, (data, result) => {
   data.microsecond = +fraction.slice(3, 6);
   data.nanosecond = +fraction.slice(6, 9);
 });
+
 function saveOffset(data, result) {
   data.offset = ES.ParseDateTimeUTCOffset(result);
 }
-
-const utcOffsetWithSubMinuteComponents = (extended) =>
-  seq(temporalSign, hour, timeSeparator(extended), minuteSecond, timeSeparator(extended), minuteSecond, [
-    temporalDecimalFraction
+const utcOffset = (subMinutePrecision) =>
+  seq(temporalSign, hour, [
+    choice(
+      seq(
+        timeSeparator(true),
+        minuteSecond,
+        subMinutePrecision ? [timeSeparator(true), minuteSecond, [temporalDecimalFraction]] : empty
+      ),
+      seq(
+        timeSeparator(false),
+        minuteSecond,
+        subMinutePrecision ? [timeSeparator(false), minuteSecond, [temporalDecimalFraction]] : empty
+      )
+    )
   ]);
-const utcOffsetMinutePrecision = seq(temporalSign, hour, [
-  choice(seq(timeSeparator(true), minuteSecond), seq(timeSeparator(false), minuteSecond))
-]);
-const utcOffsetSubMinutePrecision = withCode(
-  choice(utcOffsetMinutePrecision, utcOffsetWithSubMinuteComponents(true), utcOffsetWithSubMinuteComponents(false)),
-  saveOffset
-);
-const dateTimeUTCOffset = (z) => (z ? choice(utcDesignator, utcOffsetSubMinutePrecision) : utcOffsetSubMinutePrecision);
-const timeZoneUTCOffsetName = utcOffsetMinutePrecision;
+const dateTimeUTCOffset = (z) =>
+  z ? choice(utcDesignator, withCode(utcOffset(true), saveOffset)) : withCode(utcOffset(true), saveOffset);
+const timeZoneUTCOffsetName = utcOffset(false);
 const timeZoneIANAName = choice(...timezoneNames);
 const timeZoneIdentifier = withCode(
   choice(timeZoneUTCOffsetName, timeZoneIANAName),

diff --git a/spec/abstractops.html b/spec/abstractops.html
@@ -1278,28 +1278,22 @@ <h1>ISO 8601 grammar</h1>
       TimeFraction :::
           TemporalDecimalFraction
 
-      UTCOffsetWithSubMinuteComponents[Extended] :::
-          TemporalSign Hour TimeSeparator[?Extended] MinuteSecond TimeSeparator[?Extended] MinuteSecond TemporalDecimalFraction?
-
       NormalizedUTCOffset :::
           ASCIISign Hour TimeSeparator[+Extended] MinuteSecond
 
-      UTCOffsetMinutePrecision :::
+      UTCOffset[SubMinutePrecision] :::
           TemporalSign Hour
           TemporalSign Hour TimeSeparator[+Extended] MinuteSecond
           TemporalSign Hour TimeSeparator[~Extended] MinuteSecond
-
-      UTCOffsetSubMinutePrecision :::
-          UTCOffsetMinutePrecision
-          UTCOffsetWithSubMinuteComponents[+Extended]
-          UTCOffsetWithSubMinuteComponents[~Extended]
+          [+SubMinutePrecision] TemporalSign Hour TimeSeparator[+Extended] MinuteSecond TimeSeparator[+Extended] MinuteSecond TemporalDecimalFraction?
+          [+SubMinutePrecision] TemporalSign Hour TimeSeparator[~Extended] MinuteSecond TimeSeparator[~Extended] MinuteSecond TemporalDecimalFraction?
 
       DateTimeUTCOffset[Z] :::
           [+Z] UTCDesignator
-          UTCOffsetSubMinutePrecision
+          UTCOffset[+SubMinutePrecision]
 
       TimeZoneUTCOffsetName :::
-          UTCOffsetMinutePrecision
+          UTCOffset[~SubMinutePrecision]
 
       TZLeadingChar :::
           Alpha
@@ -1631,8 +1625,8 @@ <h1>
         1. Set _timeZoneResult_.[[TimeZoneAnnotation]] to CodePointsToString(_identifier_).
       1. If _parseResult_ contains a |UTCDesignator| Parse Node, then
         1. Set _timeZoneResult_.[[Z]] to *true*.
-      1. Else if _parseResult_ contains a |UTCOffsetSubMinutePrecision| Parse Node, then
-        1. Let _offset_ be the source text matched by the |UTCOffsetSubMinutePrecision| Parse Node contained within _parseResult_.
+      1. Else if _parseResult_ contains a |UTCOffset[+SubMinutePrecision]| Parse Node, then
+        1. Let _offset_ be the source text matched by the |UTCOffset[+SubMinutePrecision]| Parse Node contained within _parseResult_.
         1. Set _timeZoneResult_.[[OffsetString]] to CodePointsToString(_offset_).
       1. Return the Record {
           [[Year]]: _yearMV_,

diff --git a/spec/intl.html b/spec/intl.html
@@ -650,7 +650,7 @@ <h1>
           1. <ins>If _toLocaleStringTimeZone_ is present, throw a *TypeError* exception.</ins>
           1. Set _timeZone_ to ? ToString(_timeZone_).
         1. If IsTimeZoneOffsetString(_timeZone_) is *true*, then
-          1. Let _parseResult_ be ParseText(StringToCodePoints(_timeZone_), <del>|UTCOffset|</del><ins>|UTCOffsetMinutePrecision|</ins>).
+          1. Let _parseResult_ be ParseText(StringToCodePoints(_timeZone_), <del>|UTCOffset|</del><ins>|UTCOffset[~SubMinutePrecision]|</ins>).
           1. Assert: _parseResult_ is a Parse Node.
           1. <del>If _parseResult_ contains more than one |MinuteSecond| Parse Node, throw a *RangeError* exception.</del>
           1. Let _offsetNanoseconds_ be <del>ParseTimeZoneOffsetString</del><ins>? ParseDateTimeUTCOffset</ins>(_timeZone_).

diff --git a/spec/mainadditions.html b/spec/mainadditions.html
@@ -252,8 +252,8 @@ <h1>Time Zone Offset String <del>Format</del><ins>Formats</ins></h1>
       <ins class="block">
       <p>
         ECMAScript defines string interchange formats for UTC offsets, derived from ISO 8601.
-        UTC offsets that represent offset time zone identifiers, or that are intended for interoperability with ISO 8601, use only hours and minutes and are specified by |UTCOffsetMinutePrecision|.
-        UTC offsets that represent the offset of a named or custom time zone can be more precise, and are specified by |UTCOffsetSubMinutePrecision|.
+        UTC offsets that represent offset time zone identifiers, or that are intended for interoperability with ISO 8601, use only hours and minutes and are specified by |UTCOffset[~SubMinutePrecision]|.
+        UTC offsets that represent the offset of a named or custom time zone can be more precise, and are specified by |UTCOffset[+SubMinutePrecision]|.
       </p>
       <p>
         These formats are described by the ISO String grammar in <emu-xref href="#sec-temporal-iso8601grammar"></emu-xref>.
@@ -461,7 +461,7 @@ <h1>
         </dd>
       </dl>
       <emu-alg>
-        1. Let _parseResult_ be ParseText(StringToCodePoints(_offsetString_), <del>|UTCOffset|</del><ins>|UTCOffsetSubMinutePrecision|</ins>).
+        1. Let _parseResult_ be ParseText(StringToCodePoints(_offsetString_), <del>|UTCOffset|</del><ins>|UTCOffset[+SubMinutePrecision]|</ins>).
         1. <del>Assert: _parseResult_ is not a List of errors.</del>
         1. <ins>If _parseResult_ is a List of errors, throw a *RangeError* exception.</ins>
         1. Assert: _parseResult_ contains a |TemporalSign| Parse Node.