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 {
}
%{
+static void yyerror(YYLTYPE *, yyscan_t, struct cdecl **, const char *);
static void free_decl(struct cdecl *);
static void free_declspec(struct cdecl_declspec *x)
free_decl(decl);
}
-static void
-yyerror(YYLTYPE *loc, yyscan_t scanner, struct cdecl **out, const char *err)
+/*
+ * Join two declaration specifier lists into a single list, with "a" being the
+ * head of the new list.
+ *
+ * The list "a" is assumed to be nonempty.
+ */
+static void join_specs(struct cdecl_declspec *a, struct cdecl_declspec *b)
{
- if (strstr(err, "T_LEX_ERROR"))
- return;
+ while (a->next)
+ a = a->next;
+ a->next = b;
+}
- cdecl__err(CDECL_ENOPARSE, "%s", err);
+/*
+ * Alter an abstract declarator (type name) to declare an identifier instead,
+ * used by the English parser rules to reduce "identifier as type" sequences.
+ */
+static struct cdecl *insert_identifier(struct cdecl *decl, char *ident)
+{
+ struct cdecl_declarator *d = decl->declarators;
+
+ while (d->child)
+ d = d->child;
+
+ d->type = CDECL_DECL_IDENT;
+ d->u.ident = ident;
+
+ return decl;
}
%}
/* Magic tokens */
%token T_LEX_ERROR
-%token T_ENGLISH
%token <strval> T_IDENT "identifier"
%token <uintval> T_UINT "integer constant"
%token T_VLA "variable-length"
%type <strval> vla_ident
+%type <uintval> array_length
%type <boolval> varargs
%type <spectype> declspec_simple qualifier_simple
%type <spectype> typespec_simple typespec_tagged
%type <declarator> direct_declarator declarator pointer array parens postfix
%type <declarator> direct_declarator_ish declarator_ish parameter_type_list
%type <decl> declaration declarators declarator_wrap
-%type <decl> parameter parameters
+%type <decl> parameter
%type <strval> english_vla
%type <declspec> storage_func_specs post_specs
%type <declspec> type_qual_spec type_qual_specs typedef_name_qual
%type <declarator> english_declarator english_array english_function
%type <declarator> english_parameter_list null_decl
-%type <decl> english_parameter english_parameters
%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;
};
declaration: declspecs declarators semi {
$$ = $2;
-
- for (struct cdecl *i = $$; i; i = i->next)
- i->specifiers = $1;
+ $$->specifiers = $1;
};
+/*
+ * We support parsing declarations using arbitrary identifiers as type
+ * specifiers (a la C typedef). To avoid confusion with identifiers that
+ * may also be used as declarators, note the following:
+ *
+ * (a) Every valid C declaration must have at least one type specifier, and
+ * (b) Valid declarations with typedef names have exactly one type specifier.
+ *
+ * So the rule applied when parsing specifiers is: an identifier is a type
+ * specifier only if we have not yet seen any type specifiers whatsoever
+ * (within one declaration specifier list).
+ *
+ * Treating identifiers as type specifiers by default can lead to strange and
+ * unexpected parses; libcdecl applies a simplification step to the resulting
+ * parse tree afterwards.
+ */
declspecs: declspec_notype declspecs {
$$ = $1;
$$->next = $2;
| T_COMPLEX
| T_IMAGINARY
-typespec_tagged: T_STRUCT | T_UNION | T_ENUM
+typespec_tagged: T_STRUCT | T_UNION | T_ENUM | { $$ = CDECL_TYPE_IDENT; }
qualifier_simple: T_CONST
| T_RESTRICT
ALLOC_STRUCT($$, struct cdecl_declspec,
.type = $1,
.ident = $2);
-} | T_IDENT {
- ALLOC_STRUCT($$, struct cdecl_declspec,
- .type = CDECL_TYPE_IDENT,
- .ident = $1);
}
declspec_noid: declspec_notype | typespec_noid
vla_ident: T_IDENT | T_ASTERISK {
ALLOC($$, sizeof "");
- strcpy($$, "");
+ *$$ = 0;
}
-array: T_LBRACKET T_UINT T_RBRACKET {
- if ($2 == 0)
- FAIL(_("array length must be positive"));
-
+array: T_LBRACKET array_length T_RBRACKET {
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_ARRAY,
.u.array.length = $2);
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_ARRAY,
.u.array.vla = $2);
-} | T_LBRACKET T_RBRACKET {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY);
}
parameter: declspecs declarator {
.declarators = $2);
}
-parameters: parameter | parameters T_COMMA parameter {
- $$ = $3;
- $$->next = $1;
-}
-
varargs: { $$ = false; } | T_COMMA T_ELLIPSIS { $$ = true; }
-parameter_type_list: parameters varargs {
- struct cdecl *p, *c, *n;
-
- /* Parameters were accumulated in reverse order. */
- for (p = NULL, c = $1; c; p = c, c = n) {
- n = c->next;
- c->next = p;
- }
-
+parameter_type_list: parameter varargs {
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_FUNCTION,
- .u.function.parameters = p,
+ .u.function.parameters = $1,
.u.function.variadic = $2);
+} | parameter T_COMMA parameter_type_list {
+ $$ = $3;
+ $1->next = $$->u.function.parameters;
+ $$->u.function.parameters = $1;
}
parens: T_LPAREN parameter_type_list T_RPAREN {
}
english: T_DECLARE T_IDENT T_AS english_declaration {
- $$ = $4;
- for (struct cdecl_declarator *d = $$->declarators; d; d = d->child) {
- if (d->type == CDECL_DECL_NULL) {
- d->type = CDECL_DECL_IDENT;
- d->u.ident = $2;
- }
- }
+ $$ = insert_identifier($4, $2);
} | T_TYPE english_declaration {
$$ = $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($$, struct cdecl_declspec,
.type = $1,
.next = $2);
* together three different specifiers lists.
*/
post_specs: qualifiers typespec type_qual_specs {
+ $2->next = $3;
+ join_specs($2, $1);
$$ = $2;
- $$->next = $1;
- for (struct cdecl_declspec *s = $$; s; s = s->next) {
- if (!s->next) {
- s->next = $3;
- break;
- }
- }
}
english_declaration: storage_func_specs english_declarator post_specs {
+ join_specs($3, $1);
ALLOC_STRUCT($$, struct cdecl,
.specifiers = $3,
.declarators = $2);
-
- for (struct cdecl_declspec *s = $$->specifiers; s; s = s->next) {
- if (!s->next) {
- s->next = $1;
- break;
- }
- }
}
english_declarator: {
$$ = $3;
}
-english_parameter_list: english_parameters varargs {
- struct cdecl *p, *c, *n;
-
- /* Parameters were accumulated in reverse order. */
- for (p = NULL, c = $1; c; p = c, c = n) {
- n = c->next;
- c->next = p;
- }
-
+english_parameter_list: english_parameter varargs {
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_FUNCTION,
- .u.function.parameters = p,
+ .u.function.parameters = $1,
.u.function.variadic = $2);
-}
-
-english_parameters: english_parameters T_COMMA english_parameter {
+} | english_parameter T_COMMA english_parameter_list {
$$ = $3;
- $$->next = $1;
-} | english_parameter
+ $1->next = $$->u.function.parameters;
+ $$->u.function.parameters = $1;
+}
typedef_name_qual: T_IDENT qualifiers {
ALLOC_STRUCT($$, struct cdecl_declspec,
}
/*
- * There is a small shift/reduce conflict here. An unadorned identifier
- * as the first thing in the parameter might be a typedef name deep in the
- * first english_declaration (thus empty storage_func_specs and empty
- * english_declarator need to be reduced) or it might be the identifier
- * before the "as" (thus the identifier should be shifted).
+ * There is a shift/reduce conflict here when an identifier appears as the
+ * first token. The conflict is between shifting T_IDENT, or reducing the
+ * empty production for storage_func_specs (cf. english_declaration).
*
- * The typedef name conflict is the only issue, so treating it as a special
- * case makes the shift harmless.
+ * - In either case, if we reduce, we won't match T_IDENT T_AS since the
+ * stack now has the extra storage_func_specs nonterminal symbol.
+ * - And if we shift, we won't match english_declaration since it is
+ * too late to add storage_func_specs to the stack.
+ *
+ * The only valid input affected by the conflict is a simple type names,
+ * possibly followed by qualifiers. So the conflict is adequately resolved
+ * by shifting, so long as we have a special-case reduction to handle this.
*/
english_parameter: english_declaration | typedef_name_qual null_decl {
ALLOC_STRUCT($$, struct cdecl,
.specifiers = $1,
.declarators = $2);
} | T_IDENT T_AS english_declaration {
- $$ = $3;
- for (struct cdecl_declarator *d = $$->declarators; d; d = d->child) {
- if (d->type == CDECL_DECL_NULL) {
- d->type = CDECL_DECL_IDENT;
- d->u.ident = $1;
- }
- }
+ $$ = insert_identifier($3, $1);
}
english_array: T_VLA T_ARRAY english_vla T_OF {
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_ARRAY,
.u.array.vla = $3);
-} | T_ARRAY T_UINT T_OF {
- if ($2 == 0)
- FAIL(_("array length must be positive"));
-
+} | T_ARRAY array_length T_OF {
ALLOC_STRUCT($$, struct cdecl_declarator,
.type = CDECL_DECL_ARRAY,
.u.array.length = $2);
-} | T_ARRAY T_OF {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY,
- .u.array.length = 0);
+}
+
+array_length: { $$ = 0; }
+array_length: T_UINT {
+ if (!($$ = $1))
+ FAIL(_("array length must be positive"));
}
english_vla: T_IDENT | {
ALLOC($$, sizeof "");
- strcpy($$, "");
+ *$$ = 0;
}
%%
{
return yytname[YYTRANSLATE(token)];
}
+
+static void
+yyerror(YYLTYPE *loc, yyscan_t scanner, struct cdecl **out, const char *err)
+{
+ if (strstr(err, yytname[YYTRANSLATE(T_LEX_ERROR)]))
+ return;
+
+ cdecl__err(CDECL_ENOPARSE, "%s", err);
+}
projects / cdecl99.git / blobdiff