Editorial: Improve PartitionDateTimeRangePattern

spec/datetimeformat.html

@@ -1049,71 +1049,65 @@ <h1>PartitionDateTimeRangePattern ( _dateTimeFormat_, _x_, _y_ )</h1>
         The PartitionDateTimeRangePattern abstract operation is called with arguments _dateTimeFormat_ (which must be an object initialized as a DateTimeFormat), _x_ (which must be a Number value) and _y_ (which must be a Number value), interprets _x_ and _y_ as time values as specified in es2023, <emu-xref href="#sec-time-values-and-time-range"></emu-xref>, and creates the corresponding parts according to the effective locale and the formatting options of _dateTimeFormat_. The following steps are taken:
       </p>
       <emu-alg>
-        1. Let _x_ be TimeClip(_x_).
+        1. Set _x_ to TimeClip(_x_).
         1. If _x_ is *NaN*, throw a *RangeError* exception.
-        1. Let _y_ be TimeClip(_y_).
+        1. Set _y_ to TimeClip(_y_).
         1. If _y_ is *NaN*, throw a *RangeError* exception.
         1. Let _tm1_ be ToLocalTime(ℤ(ℝ(_x_) &times; 10<sup>6</sup>), _dateTimeFormat_.[[Calendar]], _dateTimeFormat_.[[TimeZone]]).
         1. Let _tm2_ be ToLocalTime(ℤ(ℝ(_y_) &times; 10<sup>6</sup>), _dateTimeFormat_.[[Calendar]], _dateTimeFormat_.[[TimeZone]]).
         1. Let _rangePatterns_ be _dateTimeFormat_.[[RangePatterns]].
-        1. Let _rangePattern_ be *undefined*.
-        1. Let _dateFieldsPracticallyEqual_ be *true*.
-        1. Let _patternContainsLargerDateField_ be *false*.
-        1. While _dateFieldsPracticallyEqual_ is *true* and _patternContainsLargerDateField_ is *false*, repeat for each row of <emu-xref href="#table-datetimeformat-rangepatternfields"></emu-xref> in order, except the header row:
+        1. Let _selectedRangePattern_ be *undefined*.
+        1. Let _relevantFieldsEqual_ be *true*.
+        1. Let _checkMoreFields_ be *true*.
+        1. For each row of <emu-xref href="#table-datetimeformat-rangepatternfields"></emu-xref>, except the header row, in table order, do
           1. Let _fieldName_ be the name given in the Range Pattern Field column of the row.
-          1. If _rangePatterns_ has a field [[&lt;_fieldName_&gt;]], let _rp_ be _rangePatterns_.[[&lt;_fieldName_&gt;]]; else let _rp_ be *undefined*.
-          1. If _rangePattern_ is not *undefined* and _rp_ is *undefined*, then
-            1. Set _patternContainsLargerDateField_ to *true*.
-          1. Else,
-            1. Let _rangePattern_ be _rp_.
+          1. If _rangePatterns_ has a field [[&lt;_fieldName_&gt;]], let _rangePattern_ be _rangePatterns_.[[&lt;_fieldName_&gt;]]; else let _rangePattern_ be *undefined*.
+          1. If _selectedRangePattern_ is not *undefined* and _rangePattern_ is *undefined*, then
+            1. NOTE: Because there is no range pattern for differences at or below this field, no further checks will be performed.
+            1. Set _checkMoreFields_ to *false*.
+          1. If _relevantFieldsEqual_ is *true* and _checkMoreFields_ is *true*, then
+            1. Set _selectedRangePattern_ to _rangePattern_.
             1. If _fieldName_ is equal to [[AmPm]], then
-              1. Let _v1_ be _tm1_.[[Hour]].
-              1. Let _v2_ be _tm2_.[[Hour]].
-              1. If _v1_ is greater than 11 and _v2_ less or equal than 11, or _v1_ is less or equal than 11 and _v2_ is greater than 11, then
-                1. Set _dateFieldsPracticallyEqual_ to *false*.
+              1. If _tm1_.[[Hour]] is less than 12, let _v1_ be *"am"*; else let _v1_ be *"pm"*.
+              1. If _tm2_.[[Hour]] is less than 12, let _v2_ be *"am"*; else let _v2_ be *"pm"*.
             1. Else if _fieldName_ is equal to [[DayPeriod]], then
               1. Let _v1_ be a String value representing the day period of _tm1_; the String value depends upon the implementation and the effective locale of _dateTimeFormat_.
               1. Let _v2_ be a String value representing the day period of _tm2_; the String value depends upon the implementation and the effective locale of _dateTimeFormat_.
-              1. If _v1_ is not equal to _v2_, then
-                1. Set _dateFieldsPracticallyEqual_ to *false*.
             1. Else if _fieldName_ is equal to [[FractionalSecondDigits]], then
               1. Let _fractionalSecondDigits_ be _dateTimeFormat_.[[FractionalSecondDigits]].
               1. If _fractionalSecondDigits_ is *undefined*, then
                 1. Set _fractionalSecondDigits_ to 3.
-              1. Let _v1_ be _tm1_.[[Millisecond]].
-              1. Let _v2_ be _tm2_.[[Millisecond]].
-              1. Let _v1_ be floor(_v1_ &times; 10<sup>( _fractionalSecondDigits_ - 3 )</sup>).
-              1. Let _v2_ be floor(_v2_ &times; 10<sup>( _fractionalSecondDigits_ - 3 )</sup>).
-              1. If _v1_ is not equal to _v2_, then
-                1. Set _dateFieldsPracticallyEqual_ to *false*.
+              1. Let _exp_ be _fractionalSecondDigits_ - 3.
+              1. Let _v1_ be floor(_tm1_.[[Millisecond]] &times; 10<sup>_exp_</sup>).
+              1. Let _v2_ be floor(_tm2_.[[Millisecond]] &times; 10<sup>_exp_</sup>).
             1. Else,
               1. Let _v1_ be _tm1_.[[&lt;_fieldName_&gt;]].
               1. Let _v2_ be _tm2_.[[&lt;_fieldName_&gt;]].
-              1. If _v1_ is not equal to _v2_, then
-                1. Set _dateFieldsPracticallyEqual_ to *false*.
-        1. If _dateFieldsPracticallyEqual_ is *true*, then
+            1. If _v1_ is not equal to _v2_, then
+              1. Set _relevantFieldsEqual_ to *false*.
+        1. If _relevantFieldsEqual_ is *true*, then
+          1. Let _collapsedResult_ be a new empty List.
           1. Let _pattern_ be _dateTimeFormat_.[[Pattern]].
           1. Let _patternParts_ be PartitionPattern(_pattern_).
-          1. Let _result_ be ? FormatDateTimePattern(_dateTimeFormat_, _patternParts_, _x_, *undefined*).
-          1. For each Record { [[Type]], [[Value]] } _r_ in _result_, do
-            1. Set _r_.[[Source]] to *"shared"*.
-          1. Return _result_.
-        1. Let _result_ be a new empty List.
-        1. If _rangePattern_ is *undefined*, then
-          1. Let _rangePattern_ be _rangePatterns_.[[Default]].
-        1. For each Record { [[Pattern]], [[Source]] } _rangePatternPart_ in _rangePattern_.[[PatternParts]], do
+          1. Let _resultParts_ be ? FormatDateTimePattern(_dateTimeFormat_, _patternParts_, _x_, *undefined*).
+          1. For each Record { [[Type]], [[Value]] } _r_ in _resultParts_, do
+            1. Append a new Record { [[Type]]: _r_.[[Type]], [[Value]]: _r_.[[Value]], [[Source]]: *"shared"* } as the last element of _collapsedResult_.
+          1. Return _collapsedResult_.
+        1. Let _rangeResult_ be a new empty List.
+        1. If _selectedRangePattern_ is *undefined*, then
+          1. Set _selectedRangePattern_ to _rangePatterns_.[[Default]].
+        1. For each Record { [[Pattern]], [[Source]] } _rangePatternPart_ in _selectedRangePattern_.[[PatternParts]], do
           1. Let _pattern_ be _rangePatternPart_.[[Pattern]].
           1. Let _source_ be _rangePatternPart_.[[Source]].
           1. If _source_ is *"startRange"* or *"shared"*, then
             1. Let _z_ be _x_.
           1. Else,
             1. Let _z_ be _y_.
           1. Let _patternParts_ be PartitionPattern(_pattern_).
-          1. Let _partResult_ be ? FormatDateTimePattern(_dateTimeFormat_, _patternParts_, _z_, _rangePattern_).
-          1. For each Record { [[Type]], [[Value]] } _r_ in _partResult_, do
-            1. Set _r_.[[Source]] to _source_.
-          1. Add all elements in _partResult_ to _result_ in order.
-        1. Return _result_.
+          1. Let _resultParts_ be ? FormatDateTimePattern(_dateTimeFormat_, _patternParts_, _z_, _selectedRangePattern_).
+          1. For each Record { [[Type]], [[Value]] } _r_ in _resultParts_, do
+            1. Append a new Record { [[Type]]: _r_.[[Type]], [[Value]]: _r_.[[Value]], [[Source]]: _source_ } as the last element of _rangeResult_.
+        1. Return _rangeResult_.
       </emu-alg>
     </emu-clause>