[ovs-dev] [PATCH 02/10] lex: Make lexer_force_match() work for LEX_T_END.

[Ben Pfaff]

Without this change, lexer_force_match(lex, LEX_T_END) mostly works, except
that in the failure case it emits an error that says "expecting `$'",
which is a surprising error message.

Arguably, lexer_force_end() could be removed entirely, but I don't see a
real problem with the existing arrangement.

Signed-off-by: Ben Pfaff <blp at ovn.org>
---
 include/ovn/lex.h |  4 ++--
 ovn/lib/lex.c     | 13 +++++++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/include/ovn/lex.h b/include/ovn/lex.h
index 0876d1b..afa4a23 100644
--- a/include/ovn/lex.h
+++ b/include/ovn/lex.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016 Nicira, Inc.
+ * Copyright (c) 2015, 2016, 2017 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -139,7 +139,7 @@ bool lexer_is_int(const struct lexer *);
 bool lexer_get_int(struct lexer *, int *value);
 bool lexer_force_int(struct lexer *, int *value);
 
-void lexer_force_end(struct lexer *);
+bool lexer_force_end(struct lexer *);
 
 void lexer_error(struct lexer *, const char *message, ...)
     OVS_PRINTF_FORMAT(2, 3);
diff --git a/ovn/lib/lex.c b/ovn/lib/lex.c
index d64ce83..4b504cb 100644
--- a/ovn/lib/lex.c
+++ b/ovn/lib/lex.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016 Nicira, Inc.
+ * Copyright (c) 2015, 2016, 2017 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -856,7 +856,9 @@ lexer_match(struct lexer *lexer, enum lex_type type)
 bool
 lexer_force_match(struct lexer *lexer, enum lex_type t)
 {
-    if (lexer_match(lexer, t)) {
+    if (t == LEX_T_END) {
+        return lexer_force_end(lexer);
+    } else if (lexer_match(lexer, t)) {
         return true;
     } else {
         struct lex_token token = { .type = t };
@@ -915,11 +917,14 @@ lexer_force_int(struct lexer *lexer, int *value)
     return ok;
 }
 
-void
+bool
 lexer_force_end(struct lexer *lexer)
 {
-    if (lexer->token.type != LEX_T_END) {
+    if (lexer->token.type == LEX_T_END) {
+        return true;
+    } else {
         lexer_syntax_error(lexer, "expecting end of input");
+        return false;
     }
 }
 
-- 
2.10.2