fix(parser): name the unexpected token in expression diagnostics

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/cps/Lexer.h b/include/cps/Lexer.h
index 247c8d0..bec1233 100644
--- a/include/cps/Lexer.h
+++ b/include/cps/Lexer.h
@@ -154,6 +154,8 @@ public:
     int getLine() const { return TokenLine; }
     bool isLibrary() const { return Library; }
     bool hadError() const { return HadError; }
+    // Human-readable spelling of Tok for diagnostics; Lex supplies identifier text.
+    static std::string tokenSpelling(int Tok, const Lexer &Lex);
 };
 
 }