From c51eee0e521c27277c8ef1a64f91249473287617 Mon Sep 17 00:00:00 2001
From: Michael Dyck <jmdyck@ibiblio.org>
Date: Tue, 20 Aug 2019 15:48:03 -0400
Subject: [PATCH] Editorial: Merge 'ExtendedAtom' and 'Atom'

Note that:

ExtendedAtom was only ever 'invoked' under [~U],
and when the merged production is invoked with [~U],
it exactly reproduces the RHSs of ExtendedAtom.

Atom was only ever invoked under [+U],
and when the merged production is invoked with [+U],
it reproduces the RHSs of former Atom
except for the placement of the PatternCharacter RHS,
but that's okay, because former Atom wasn't an order-disambiguated production.
---
 spec.html | 49 +++++++++++++++++++------------------------------
 1 file changed, 19 insertions(+), 30 deletions(-)

diff --git a/spec.html b/spec.html
index 2e6d9b16edc..84b4e3a361a 100644
--- a/spec.html
+++ b/spec.html
@@ -29494,8 +29494,8 @@ <h2>Patterns</h2>
           [+U] Atom[+U, ?N] Quantifier
           [~U] QuantifiableAssertion[~U, ?N] Quantifier
           [~U] Assertion[~U, ?N]
-          [~U] ExtendedAtom[?N] Quantifier
-          [~U] ExtendedAtom[?N]
+          [~U] Atom[~U, ?N] Quantifier
+          [~U] Atom[~U, ?N]
 
         Assertion[U, N] ::
           `^`
@@ -29522,23 +29522,17 @@ <h2>Patterns</h2>
           `{` DecimalDigits `,` `}`
           `{` DecimalDigits `,` DecimalDigits `}`
 
-        ExtendedAtom[N] ::!
-          `.`
-          `\` AtomEscape[~U, ?N]
-          `\` [lookahead == `c`]
-          CharacterClass[~U]
-          `(` Disjunction[~U, ?N] `)`
-          `(` `?` `:` Disjunction[~U, ?N] `)`
-          InvalidBracedQuantifier
-          ExtendedPatternCharacter
-
-        Atom[U, N] ::
-          PatternCharacter
+        Atom[U, N] ::!
           `.`
           `\` AtomEscape[?U, ?N]
+          [~U] `\` [lookahead == `c`]
           CharacterClass[?U]
-          `(` GroupSpecifier[?U] Disjunction[?U, ?N] `)`
+          [+U] `(` GroupSpecifier[?U] Disjunction[?U, ?N] `)`
+          [~U] `(` Disjunction[?U, ?N] `)`
           `(` `?` `:` Disjunction[?U, ?N] `)`
+          [~U] InvalidBracedQuantifier
+          [+U] PatternCharacter
+          [~U] ExtendedPatternCharacter
 
         InvalidBracedQuantifier ::
           `{` DecimalDigits `}`
@@ -29762,7 +29756,7 @@ <h1>Static Semantics: Early Errors</h1>
             It is a Syntax Error if the MV of the first |DecimalDigits| is larger than the MV of the second |DecimalDigits|.
           </li>
         </ul>
-        <emu-grammar>ExtendedAtom :: InvalidBracedQuantifier</emu-grammar>
+        <emu-grammar>Atom :: InvalidBracedQuantifier</emu-grammar>
         <ul>
           <li>
             It is a Syntax Error if any source text matches this rule.
@@ -30273,10 +30267,8 @@ <h1>Term</h1>
             1. Call RepeatMatcher(_m_, _min_, _max_, _greedy_, _x_, _c_, _parenIndex_, _parenCount_) and return its result.
         </emu-alg>
         <p>----</p>
-        <p>In the above algorithm, references to <emu-grammar>Atom :: `(` GroupSpecifier Disjunction `)`</emu-grammar> are to be interpreted as meaning <emu-grammar>Atom :: `(` GroupSpecifier Disjunction `)`</emu-grammar> or <emu-grammar>ExtendedAtom :: `(` Disjunction `)`</emu-grammar> .</p>
+        <p>In the above algorithm, references to <emu-grammar>Atom :: `(` GroupSpecifier Disjunction `)`</emu-grammar> are to be interpreted as meaning <emu-grammar>Atom :: `(` GroupSpecifier Disjunction `)`</emu-grammar> or <emu-grammar>Atom :: `(` Disjunction `)`</emu-grammar> .</p>
         <p>The production <emu-grammar>Term :: QuantifiableAssertion Quantifier</emu-grammar> evaluates the same as the production <emu-grammar>Term :: Atom Quantifier</emu-grammar> but with |QuantifiableAssertion| substituted for |Atom|.</p>
-        <p>The production <emu-grammar>Term :: ExtendedAtom Quantifier</emu-grammar> evaluates the same as the production <emu-grammar>Term :: Atom Quantifier</emu-grammar> but with |ExtendedAtom| substituted for |Atom|.</p>
-        <p>The production <emu-grammar>Term :: ExtendedAtom</emu-grammar> evaluates the same as the production <emu-grammar>Term :: Atom</emu-grammar> but with |ExtendedAtom| substituted for |Atom|.</p>
 
         <emu-clause id="sec-runtime-semantics-repeatmatcher-abstract-operation" aoid="RepeatMatcher">
           <h1>Runtime Semantics: RepeatMatcher ( _m_, _min_, _max_, _greedy_, _x_, _c_, _parenIndex_, _parenCount_ )</h1>
@@ -30737,12 +30729,6 @@ <h1>Quantifier</h1>
       <emu-clause id="sec-atom">
         <h1>Atom</h1>
         <p>With parameter _direction_.</p>
-        <p>The production <emu-grammar>Atom :: PatternCharacter</emu-grammar> evaluates as follows:</p>
-        <emu-alg>
-          1. Let _ch_ be the character matched by |PatternCharacter|.
-          1. Let _A_ be a one-element CharSet containing the character _ch_.
-          1. Call CharacterSetMatcher(_A_, *false*, _direction_) and return its Matcher result.
-        </emu-alg>
         <p>The production <emu-grammar>Atom :: `.`</emu-grammar> evaluates as follows:</p>
         <emu-alg>
           1. If _DotAll_ is *true*, then
@@ -30754,7 +30740,7 @@ <h1>Atom</h1>
         <emu-alg>
           1. Return the Matcher that is the result of evaluating |AtomEscape| with argument _direction_.
         </emu-alg>
-        <p>The production <emu-grammar>ExtendedAtom :: `\` [lookahead == `c`]</emu-grammar> evaluates as follows:</p>
+        <p>The production <emu-grammar>Atom :: `\` [lookahead == `c`]</emu-grammar> evaluates as follows:</p>
         <emu-alg>
           1. Let _A_ be the CharSet containing the single character `\\` U+005C (REVERSE SOLIDUS).
           1. Call CharacterSetMatcher(_A_, *false*) and return its Matcher result.
@@ -30789,14 +30775,18 @@ <h1>Atom</h1>
         <emu-alg>
           1. Return the Matcher that is the result of evaluating |Disjunction| with argument _direction_.
         </emu-alg>
-        <p>The production <emu-grammar>ExtendedAtom :: ExtendedPatternCharacter</emu-grammar> evaluates as follows:</p>
+        <p>The production <emu-grammar>Atom :: ExtendedPatternCharacter</emu-grammar> evaluates as follows:</p>
         <emu-alg>
           1. Let _ch_ be the character represented by |ExtendedPatternCharacter|.
           1. Let _A_ be a one-element CharSet containing the character _ch_.
           1. Call CharacterSetMatcher(_A_, *false*) and return its Matcher result.
         </emu-alg>
-        <p>----</p>
-        <p>The evaluation rules for the |Atom| productions except for <emu-grammar>Atom :: PatternCharacter</emu-grammar> are also used for the |ExtendedAtom| productions, but with |ExtendedAtom| substituted for |Atom|.</p>
+        <p>The production <emu-grammar>Atom :: PatternCharacter</emu-grammar> evaluates as follows:</p>
+        <emu-alg>
+          1. Let _ch_ be the character matched by |PatternCharacter|.
+          1. Let _A_ be a one-element CharSet containing the character _ch_.
+          1. Call CharacterSetMatcher(_A_, *false*, _direction_) and return its Matcher result.
+        </emu-alg>
 
         <emu-clause id="sec-runtime-semantics-charactersetmatcher-abstract-operation" aoid="CharacterSetMatcher">
           <h1>Runtime Semantics: CharacterSetMatcher ( _A_, _invert_, _direction_ )</h1>
@@ -40413,7 +40403,6 @@ <h1>Regular Expressions</h1>
     <emu-prodref name=QuantifiableAssertion></emu-prodref>
     <emu-prodref name=Quantifier></emu-prodref>
     <emu-prodref name=QuantifierPrefix></emu-prodref>
-    <emu-prodref name=ExtendedAtom></emu-prodref>
     <emu-prodref name=Atom></emu-prodref>
     <emu-prodref name=InvalidBracedQuantifier></emu-prodref>
     <emu-prodref name=ExtendedPatternCharacter></emu-prodref>