From b74df136fe8a46beedaed7e50e0dd44564c60cc4 Mon Sep 17 00:00:00 2001
From: Dan Klishch <danilklishch@gmail.com>
Date: Tue, 16 Jan 2024 17:44:59 -0500
Subject: [PATCH] JSSpecCompiler: Always treat trailing MemberAccess as
 punctuation

Due to the way expression parser is written, we need to resolve the
ambiguity between member access operators and dots used for punctuation
during lexing. The lexer uses a (totally bulletproof) heuristic to do
that: whenever '.' is followed by ' ' or '\n', it is considered a dot
and member access otherwise. While it works fine for prettified test
cases, non-prettified files often lack enter after a trailing dot
character. Since MemberAccess will always be invalid at that position,
explicitly treat trailing dot as a part of punctuation.
---
 .../JSSpecCompiler/Parser/Lexer.cpp           |  4 ++++
 .../Tests/spec-no-new-line-after-dot.xml      | 19 +++++++++++++++++++
 ...spec-no-new-line-after-dot.xml.expectation |  8 ++++++++
 Tests/JSSpecCompiler/test-runner.cpp          |  1 +
 4 files changed, 32 insertions(+)
 create mode 100644 Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml
 create mode 100644 Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml.expectation

diff --git a/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Parser/Lexer.cpp b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Parser/Lexer.cpp
index 5e9fd95406..e0678f30b8 100644
--- a/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Parser/Lexer.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Parser/Lexer.cpp
@@ -151,6 +151,10 @@ ParseErrorOr<TokenizeTreeResult> tokenize_tree(XML::Node const* node, bool allow
             },
             move(ignore_comments)));
     }
+
+    if (tokens.size() && tokens.last().type == TokenType::MemberAccess)
+        tokens.last().type = TokenType::Dot;
+
     return result;
 }
 
diff --git a/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml
new file mode 100644
index 0000000000..18a443406c
--- /dev/null
+++ b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml
@@ -0,0 +1,19 @@
+<!DOCTYPE inline_dtd[<!ENTITY nbsp " ">]>
+<specification>
+   <emu-import>
+      <emu-clause id="1">
+         <h1><span class="secnum">1</span> The Celestial Object</h1>
+         <emu-clause id="1-1">
+            <h1><span class="secnum">1.1</span> Abstract Operations</h1>
+            <emu-clause id="1-1-1" aoid="Foo">
+               <h1><span class="secnum">1.1.1</span> Foo ( <var>a</var> )</h1>
+               <emu-alg>
+                  <ol>
+                     <li>Return <var>a</var>.<var>[[b]]</var>.</li>
+                  </ol>
+               </emu-alg>
+            </emu-clause>
+         </emu-clause>
+      </emu-clause>
+   </emu-import>
+</specification>
diff --git a/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml.expectation b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml.expectation
new file mode 100644
index 0000000000..b84a41a8be
--- /dev/null
+++ b/Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Tests/spec-no-new-line-after-dot.xml.expectation
@@ -0,0 +1,8 @@
+===== AST after reference-resolving =====
+Foo(a):
+TreeList
+  ReturnNode
+    BinaryOperation MemberAccess
+      Var a
+      Slot b
+
diff --git a/Tests/JSSpecCompiler/test-runner.cpp b/Tests/JSSpecCompiler/test-runner.cpp
index 272aa4c95c..27df47276c 100644
--- a/Tests/JSSpecCompiler/test-runner.cpp
+++ b/Tests/JSSpecCompiler/test-runner.cpp
@@ -49,6 +49,7 @@ const Array regression_tests = {
     },
     TestDescription {
         .sources = {
+            "spec-no-new-line-after-dot.xml"sv,
             "spec-single-function-simple.xml"sv,
         },
         .flags = { dump_after_frontend },