From 1817efd6dc431de0ee64c59838a62728ac735299 Mon Sep 17 00:00:00 2001
From: Werner Almesberger <werner@almesberger.net>
Date: Thu, 26 Apr 2012 03:02:48 -0300
Subject: [PATCH] b2/: add syntax switch

---
 b2/boom.c |  5 ++---
 b2/lang.h | 19 +++++++++++++++++++
 b2/lang.l | 27 +++++++++++++++++++++++++++
 b2/lang.y |  9 +++++++--
 4 files changed, 55 insertions(+), 5 deletions(-)
 create mode 100644 b2/lang.h

diff --git a/b2/boom.c b/b2/boom.c
index 1d194c3..d3dde4a 100644
--- a/b2/boom.c
+++ b/b2/boom.c
@@ -15,8 +15,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 
-
-extern int yyparse(void);
+#include "lang.h"
 
 
 static void usage(const char *name)
@@ -47,6 +46,6 @@ int main(int argc, char **argv)
 	default:
 		usage(*argv);
 	}
-	(void) yyparse();
+	parse_hierarchy();
 	return 0;
 }
diff --git a/b2/lang.h b/b2/lang.h
new file mode 100644
index 0000000..f0c966a
--- /dev/null
+++ b/b2/lang.h
@@ -0,0 +1,19 @@
+/*
+ * lang.h - Things lang.l and lang.y export
+ *
+ * Copyright 2012 by Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#ifndef LANG_H
+#define	LANG_H
+
+void parse_hierarchy(void);
+void parse_characteristics(void);
+
+#endif /* !LANG_H */
diff --git a/b2/lang.l b/b2/lang.l
index 907ffdb..85c777c 100644
--- a/b2/lang.l
+++ b/b2/lang.l
@@ -17,14 +17,41 @@
 #include "param.h"
 #include "chr.h"
 #include "y.tab.h"
+#include "lang.h"
 
 
+extern int yyparse(void);
+
+static int start_token;
 static int lineno = 1;
 
+
+void parse_hierarchy(void)
+{
+	start_token = START_HIERARCHY;
+	yyparse();
+}
+
+
+void parse_characteristics(void)
+{
+	start_token = START_CHAR;
+	yyparse();
+}
+
 %}
 
 %%
 
+%{
+	if (start_token) {
+		int tmp = start_token;
+
+		start_token = 0;
+		return tmp;
+	}
+%}
+
 [-_A-Za-z0-9()+./]+		{ yylval.s = unique(yytext);
 				  return WORD; }
 
diff --git a/b2/lang.y b/b2/lang.y
index 41c99b7..b34bb45 100644
--- a/b2/lang.y
+++ b/b2/lang.y
@@ -71,6 +71,7 @@ static const struct field *top_field(void)
 };
 
 
+%token			START_HIERARCHY START_CHAR
 %token			TOK_LE TOK_GE
 %token	<s>		WORD
 
@@ -86,11 +87,15 @@ static const struct field *top_field(void)
 %%
 
 all:
-	rule
+	START_HIERARCHY hierarchy
+	;
+
+hierarchy:
+	nameset hierarchy
+	| rule
 		{
 			field_dump(stderr, $1);
 		}
-	| nameset all
 	;
 
 nameset: