[PATCH] Change yyerror to use stdarg so we can give more descriptive errors.

[John Bonesio <bones-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

The subject pretty much says it all. The patch is to allow dtc to give more
descriptive errors by having yyerror take a variable number of parameters
printf style.

- John

---

 dtc-parser.y |   15 ++++++++++-----
 srcpos.c     |   21 +++++++++++++--------
 srcpos.h     |    2 ++
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/dtc-parser.y b/dtc-parser.y
index 0aaf8e8..aa250f1 100644
--- a/dtc-parser.y
+++ b/dtc-parser.y
@@ -27,7 +27,7 @@
 YYLTYPE yylloc;
 
 extern int yylex(void);
-extern void yyerror(char const *s);
+extern void yyerror(char const *fmt, ...);
 
 extern struct boot_info *the_boot_info;
 extern int treesource_error;
@@ -136,8 +136,8 @@ devicetree:
 			if (target)
 				merge_nodes(target, $3);
 			else
-				yyerror("label does not exist in "
-					" node redefinition");
+				yyerror("label, '%s' does not exist in"
+					" node extension", $2);
 			$$ = $1;
 		}
 	;
@@ -314,9 +314,14 @@ subnode:
 
 %%
 
-void yyerror(char const *s)
+void yyerror(char const *fmt, ...)
 {
-	srcpos_error(&yylloc, "%s", s);
+	va_list va;
+
+	va_start(va, fmt);
+	srcpos_verror(&yylloc, fmt, va);
+	va_end(va);
+
 	treesource_error = 1;
 }
 
diff --git a/srcpos.c b/srcpos.c
index 87d7f17..2dbc874 100644
--- a/srcpos.c
+++ b/srcpos.c
@@ -208,20 +208,25 @@ srcpos_string(struct srcpos *pos)
 	return pos_str;
 }
 
+void
+srcpos_verror(struct srcpos *pos, char const *fmt, va_list va)
+{
+       const char *srcstr;
+
+       srcstr = srcpos_string(pos);
+
+       fprintf(stdout, "Error: %s ", srcstr);
+       vfprintf(stdout, fmt, va);
+       fprintf(stdout, "\n");
+}
 
 void
 srcpos_error(struct srcpos *pos, char const *fmt, ...)
 {
-	const char *srcstr;
 	va_list va;
-	va_start(va, fmt);
-
-	srcstr = srcpos_string(pos);
-
-	fprintf(stderr, "Error: %s ", srcstr);
-	vfprintf(stderr, fmt, va);
-	fprintf(stderr, "\n");
 
+	va_start(va, fmt);
+	srcpos_verror(pos, fmt, va);
 	va_end(va);
 }
 
diff --git a/srcpos.h b/srcpos.h
index 985f847..bd7966e 100644
--- a/srcpos.h
+++ b/srcpos.h
@@ -76,6 +76,8 @@ extern struct srcpos *srcpos_copy(struct srcpos *pos);
 extern char *srcpos_string(struct srcpos *pos);
 extern void srcpos_dump(struct srcpos *pos);
 
+extern void srcpos_verror(struct srcpos *pos, char const *, va_list va)
+     __attribute__((format(printf, 2, 0)));
 extern void srcpos_error(struct srcpos *pos, char const *, ...)
      __attribute__((format(printf, 2, 3)));
 extern void srcpos_warn(struct srcpos *pos, char const *, ...)