From: Nick Bowler <nbowler@draconx.ca>
Date: Sat, 25 Jun 2011 13:45:16 +0000 (-0400)
Subject: Add support for array declarators.
X-Git-Tag: v1~161
X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/commitdiff_plain/b3c6b8ad6aef24301d8ec511966140757e49f815

Add support for array declarators.

Currently there is a (I think quite reasonable) restriction that the
array length either be unspecified, a positive integer constant, an
identifier, or *.
---

diff --git a/src/cdecl.h b/src/cdecl.h
index 6055ea8..9c06b79 100644
--- a/src/cdecl.h
+++ b/src/cdecl.h
@@ -2,6 +2,7 @@
 #define CEDCL_H_
 
 #include <stddef.h>
+#include <stdint.h>
 
 /* Declaration specifier kinds. */
 enum {
@@ -42,6 +43,7 @@ enum {
 enum {
 	CDECL_DECL_IDENT,
 	CDECL_DECL_POINTER,
+	CDECL_DECL_ARRAY,
 };
 
 struct cdecl {
@@ -60,6 +62,11 @@ struct cdecl {
 				struct cdecl_declspec   *qualifiers;
 				struct cdecl_declarator *declarator;
 			} pointer;
+			struct cdecl_array {
+				char *vla;
+				uintmax_t length;
+				struct cdecl_declarator *declarator;
+			} array;
 		} u;
 	} *declarators;
 };
diff --git a/src/explain.c b/src/explain.c
index c6c7e9c..d8a5f05 100644
--- a/src/explain.c
+++ b/src/explain.c
@@ -161,6 +161,8 @@ static struct cdecl_declarator *next_declarator(struct cdecl_declarator *d)
 		return NULL;
 	case CDECL_DECL_POINTER:
 		return d->u.pointer.declarator;
+	case CDECL_DECL_ARRAY:
+		return d->u.array.declarator;
 	default:
 		abort();
 	}
@@ -188,6 +190,28 @@ explain_pointer(char *buf, size_t n, struct cdecl_pointer *p)
 	return ret + snprintf(buf, n, "pointer to");
 }
 
+static size_t
+explain_array(char *buf, size_t n, struct cdecl_array *a)
+{
+	size_t ret = 0, rc = 0;
+
+	if (a->vla)
+		rc = snprintf(buf, n, "variable-length array");
+	else
+		rc = snprintf(buf, n, "array");
+	ret += advance(&buf, &n, rc);
+
+	if (a->vla) {
+		rc = snprintf(buf, n, "%s", a->vla);
+		ret += advance(&buf, &n, rc);
+	} else if (a->length) {
+		rc = snprintf(buf, n, "%ju", a->length);
+		ret += advance(&buf, &n, rc);
+	}
+
+	return ret + snprintf(buf, n, "of");
+}
+
 static size_t
 explain_declarators(char *buf, size_t n, struct cdecl_declarator *d)
 {
@@ -202,6 +226,8 @@ explain_declarators(char *buf, size_t n, struct cdecl_declarator *d)
 	switch (d->type) {
 	case CDECL_DECL_POINTER:
 		return ret + explain_pointer(buf, n, &d->u.pointer);
+	case CDECL_DECL_ARRAY:
+		return ret + explain_array(buf, n, &d->u.array);
 	default:
 		abort();
 	}
diff --git a/src/parse.y b/src/parse.y
index 7b73eae..8840279 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -84,6 +84,10 @@ static void free_declarator(struct cdecl_declarator *x)
 			free_declspec(x->u.pointer.qualifiers);
 			free_declarator(x->u.pointer.declarator);
 			break;
+		case CDECL_DECL_ARRAY:
+			free(x->u.array.vla);
+			free_declarator(x->u.array.declarator);
+			break;
 		default:
 			abort();
 		}
@@ -114,6 +118,8 @@ void cdecl_free(struct cdecl *decl)
 %token T_LEX_ERROR
 
 %token <strval> T_IDENT "identifier"
+%token <uintval> T_UINT "integer constant"
+
 %token T_SEMICOLON ";"
 %token T_ASTERISK  "*"
 %token T_LPAREN    "("
@@ -150,11 +156,12 @@ void cdecl_free(struct cdecl *decl)
 %token T_UNION    "union"
 %token T_ENUM     "enum"
 
+%type <strval>     vla_ident
 %type <uintval>    declspec_simple typespec_simple qualifier_simple
 %type <declspec>   declspec_notype declspec_noid typespec_noid typespec
 %type <declspec>   qualifier qualifiers pointer
 %type <declspec>   declspecs declspecs_noid
-%type <declarator> declarator declarators
+%type <declarator> direct_declarator declarator declarators array
 %type <decl>       declaration
 
 %%
@@ -249,15 +256,41 @@ declspec_noid: declspec_notype | typespec_noid
 
 pointer: T_ASTERISK qualifiers { $$ = $2; }
 
-declarator: T_IDENT {
+vla_ident: T_IDENT | T_ASTERISK {
+	ALLOC($$, sizeof "");
+	strcpy($$, "");
+}
+
+array: T_LBRACKET T_UINT T_RBRACKET {
+	if ($2 == 0)
+		FAIL("array length must be positive");
+
 	ALLOC_STRUCT($$, struct cdecl_declarator,
-		.type = CDECL_DECL_IDENT,
-		.u.ident = $1);
-} | pointer declarator {
+		.type = CDECL_DECL_ARRAY,
+		.u.array.length = $2);
+} | T_LBRACKET vla_ident T_RBRACKET {
+	ALLOC_STRUCT($$, struct cdecl_declarator,
+		.type = CDECL_DECL_ARRAY,
+		.u.array.vla = $2);
+} | T_LBRACKET T_RBRACKET {
+	ALLOC_STRUCT($$, struct cdecl_declarator,
+		.type = CDECL_DECL_ARRAY);
+}
+
+declarator: direct_declarator | pointer direct_declarator {
 	ALLOC_STRUCT($$, struct cdecl_declarator,
 		.type = CDECL_DECL_POINTER,
 		.u.pointer.qualifiers = $1,
 		.u.pointer.declarator = $2);
+}
+
+direct_declarator: T_IDENT {
+	ALLOC_STRUCT($$, struct cdecl_declarator,
+		.type = CDECL_DECL_IDENT,
+		.u.ident = $1);
+} | direct_declarator array {
+	$$ = $2;
+	$$->u.array.declarator = $1;
 } | T_LPAREN declarator T_RPAREN {
 	$$ = $2;
 };
diff --git a/src/scan.l b/src/scan.l
index f2e92a8..b17d4ee 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -30,6 +30,7 @@
 %}
 
 IDENT [_[:alpha:]][_[:alnum:]]*
+INTEGER 0x[[:xdigit:]]+|0[0-7]+|[[:digit:]]+
 
 %%
 
@@ -69,6 +70,19 @@ IDENT [_[:alpha:]][_[:alnum:]]*
 "union"    return T_UNION;
 "enum"     return T_ENUM;
 
+{INTEGER} {
+	char *end;
+
+	errno = 0;
+	yylval->uintval = strtoumax(yytext, &end, 0);
+	if (errno == ERANGE)
+		lex_error("integer constant out of range");
+	if (*end)
+		lex_error("invalid integer constant");
+
+	return T_UINT;
+}
+
 {IDENT} {
 	yylval->strval = malloc(yyleng+1);
 	if (!yylval->strval)