X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/blobdiff_plain/a8753bb69c0455ae59fd258aad988e9613f76330..95fee5a98002691b3cb1203b5808ec1ecfd7955b:/src/parse.y

diff --git a/src/parse.y b/src/parse.y
index a993ea6..ec7ea1b 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -53,6 +53,13 @@
 	ALLOC(ptr, sizeof (type)); \
 	*(ptr) = (type) { __VA_ARGS__ }; \
 } while (0)
+
+/*
+ * With the postprocessing performed by fix-yytname.awk, all the symbol
+ * name strings can be used directly in error messages and there is no
+ * need for any string processing.
+ */
+#define yytnamerr(a, b) cdecl__strlcpy(a, b, (a) ? INT_MAX : 0)
 %}
 
 %code requires {
@@ -181,7 +188,6 @@ static struct cdecl *insert_identifier(struct cdecl *decl, char *ident)
 
 /* Magic tokens */
 %token T_LEX_ERROR
-%token T_ENGLISH
 
 %token <strval> T_IDENT "identifier"
 %token <uintval> T_UINT "integer constant"
@@ -259,16 +265,14 @@ static struct cdecl *insert_identifier(struct cdecl *decl, char *ident)
 %type <decl>       english english_declaration
 %type <decl>       english_parameter
 
-/*
- * Harmless shift/reduce conflicts in english_parameter.  See comments below
- * for more details.
- */
-%expect 2
+/* Precedence declaration to avoid conflict in english_parameter; see below. */
+%right T_TYPE
+%right T_IDENT
 
 %%
 
-input: T_ENGLISH english {
-	*out = $2;
+input: english {
+	*out = $1;
 } | declaration {
 	*out = $1;
 };
@@ -454,7 +458,12 @@ english: T_DECLARE T_IDENT T_AS english_declaration {
 	$$ = $2;
 }
 
-storage_func_specs: { $$ = NULL; } | declspec_simple storage_func_specs {
+/*
+ * We use a precedence declaration to prefer shifting an identifier
+ * over reducing this empty rule; see below.
+ */
+storage_func_specs: %prec T_TYPE { $$ = NULL; }
+storage_func_specs: declspec_simple storage_func_specs {
 	ALLOC_STRUCT($$, struct cdecl_declspec,
 		.type = $1,
 		.next = $2);
@@ -533,14 +542,18 @@ null_decl: {
 }
 
 /*
- * There is a small shift/reduce conflict here.  An unadorned identifier
- * as the first thing in the parameter might be a typedef name deep in the
- * first english_declaration (thus empty storage_func_specs and empty
- * english_declarator need to be reduced) or it might be the identifier
- * before the "as" (thus the identifier should be shifted).
+ * There is a shift/reduce conflict here when an identifier appears as the
+ * first token.  The conflict is between shifting T_IDENT, or reducing the
+ * empty production for storage_func_specs (cf. english_declaration).
+ *
+ *   - In either case, if we reduce, we won't match T_IDENT T_AS since the
+ *     stack now has the extra storage_func_specs nonterminal symbol.
+ *   - And if we shift, we won't match english_declaration since it is
+ *     too late to add storage_func_specs to the stack.
  *
- * The typedef name conflict is the only issue, so treating it as a special
- * case makes the shift harmless.
+ * The only valid input affected by the conflict is a simple type names,
+ * possibly followed by qualifiers.  So the conflict is adequately resolved
+ * by shifting, so long as we have a special-case reduction to handle this.
  */
 english_parameter: english_declaration | typedef_name_qual null_decl {
 	ALLOC_STRUCT($$, struct cdecl,