From 0aa997a6eaad4cd730ddde283e8b156642510f32 Mon Sep 17 00:00:00 2001
From: Nick Bowler <nbowler@draconx.ca>
Date: Tue, 29 Nov 2011 20:08:54 -0500
Subject: [PATCH] Make is_abstract a proper library function.

This function is generally useful.  Add it to the public API.
---
 doc/man/libcdecl.3 | 17 ++++++++++++++---
 src/cdecl.h        |  8 ++++++++
 src/parse-decl.c   | 17 +++--------------
 3 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/doc/man/libcdecl.3 b/doc/man/libcdecl.3
index 489d7a9..8bcc394 100644
--- a/doc/man/libcdecl.3
+++ b/doc/man/libcdecl.3
@@ -17,6 +17,7 @@
 .Fd const struct cdecl_error *cdecl_get_error(void);
 .Pp
 .Fd int cdecl_spec_kind(struct cdecl_declspec *spec);
+.Fd bool cdecl_is_abstract(struct cdecl_declarator *declarator);
 .Sh DESCRIPTION
 .Nm
 provides support for parsing C declarations and translating them to something
@@ -193,11 +194,21 @@ member is interpreted as "function returning child".
 .El
 .Ss Terminal Declarators
 Null and identifier declarators have no children and are thus leaf nodes.  A
-null declarator indicates an abstract declarator; that is, one which does not
-declare any identifier.  Such declarators appear in type names and possibly
-function parameters.  An identifier declarator has the obvious meaning; the
+null declarator is not strictly a C language construct, but is used by
+.Nm
+to indicate an abstract declarator; that is, one which does not declare any
+identifier.  Such declarators appear in type names and possibly function
+parameters.  An identifier declarator has the obvious meaning; the
 .Va ident
 union member points to the C string containing the identifier.
+.Pp
+Since a null declarator may be deeply nested in the declarator chain, the
+function
+.Pp
+.Fd bool cdecl_is_abstract(struct cdecl_declarator *declarator);
+.Pp
+can be used to determine whether or not a given declarator declares an
+identifier.  The result is true if and only if the declarator is abstract.
 .Ss Pointer Declarators
 .Bd -literal -offset indent
 struct cdecl_pointer {
diff --git a/src/cdecl.h b/src/cdecl.h
index 1493d4d..695024f 100644
--- a/src/cdecl.h
+++ b/src/cdecl.h
@@ -107,6 +107,14 @@ static inline int cdecl_spec_kind(struct cdecl_declspec *spec)
 	return spec->type & ~(CDECL_SPEC_TYPE-1u);
 }
 
+static inline _Bool cdecl_is_abstract(struct cdecl_declarator *d)
+{
+	while (d->child)
+		d = d->child;
+
+	return d->type != CDECL_DECL_IDENT;
+}
+
 /* Error handling. */
 enum {
 	CDECL_ENOMEM,
diff --git a/src/parse-decl.c b/src/parse-decl.c
index 42931a3..5c8e684 100644
--- a/src/parse-decl.c
+++ b/src/parse-decl.c
@@ -27,18 +27,6 @@
 #include "i18n.h"
 #include "normalize.h"
 
-/*
- * Determine if a declarator declares an identifier (other than a function
- * parameter).
- */
-static bool is_abstract(struct cdecl_declarator *d)
-{
-	while (d->child)
-		d = d->child;
-
-	return d->type != CDECL_DECL_IDENT;
-}
-
 /*
  * Verify the declaration specifiers of a declaration.  If top is true, treat
  * this as a top-level declaration.  Otherwise, treat this as a function
@@ -48,7 +36,7 @@ static bool valid_declspecs(struct cdecl *decl, bool top)
 {
 	struct cdecl_declspec *specs = decl->specifiers;
 	struct cdecl_declarator *d   = decl->declarators;
-	bool abstract = is_abstract(d);
+	bool abstract = cdecl_is_abstract(d);
 	unsigned num_storage = 0;
 	unsigned long typemap;
 
@@ -456,7 +444,8 @@ struct cdecl *cdecl_parse_decl(const char *declstr)
 		if (!valid_declspecs(i, true))
 			goto err;
 
-		if (is_abstract(i->declarators) && (i != decl || i->next)) {
+		if (cdecl_is_abstract(i->declarators)
+		    && (i != decl || i->next)) {
 			fprintf(stderr, "mixing type names and declarations is not allowed\n");
 			goto err;
 		}
-- 
2.43.2