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FYI: fix %start after first rule
From: |
Joel E. Denny |
Subject: |
FYI: fix %start after first rule |
Date: |
Sat, 19 Aug 2006 23:15:08 -0400 (EDT) |
I've just noticed that I'm not being so consistent with how I choose where
to add test cases. Should all bugs be demonstrated in regression.at? Or
is it better to be more specific when another set, like input.at, makes
sense?
Joel
Index: ChangeLog
===================================================================
RCS file: /sources/bison/bison/ChangeLog,v
retrieving revision 1.1552
diff -p -u -r1.1552 ChangeLog
--- ChangeLog 18 Aug 2006 21:43:18 -0000 1.1552
+++ ChangeLog 20 Aug 2006 03:07:49 -0000
@@ -1,3 +1,15 @@
+2006-08-19 Joel E. Denny <address@hidden>
+
+ Allow %start after the first rule.
+ * src/reader.c (grammar_current_rule_begin): Don't set the start symbol
+ when parsing the first rule.
+ (check_and_convert_grammar): Search for it here after all grammar
+ declarations have been parsed. Skip midrules, which have dummy LHS
+ nonterminals.
+ * src/symtab.c (symbol_is_dummy): New function.
+ * src/symtab.h (symbol_is_dummy): Declare it.
+ * tests/input.at (%start after first rule): New test.
+
2006-08-18 Joel E. Denny <address@hidden>
Redo some of the previous commit: add back the ability to use
Index: src/reader.c
===================================================================
RCS file: /sources/bison/bison/src/reader.c,v
retrieving revision 1.269
diff -p -u -r1.269 reader.c
--- src/reader.c 18 Aug 2006 21:43:18 -0000 1.269
+++ src/reader.c 20 Aug 2006 03:07:49 -0000
@@ -225,13 +225,6 @@ static symbol_list *previous_rule_end =
void
grammar_current_rule_begin (symbol *lhs, location loc)
{
- if (!start_flag)
- {
- startsymbol = lhs;
- startsymbol_location = loc;
- start_flag = true;
- }
-
/* Start a new rule and record its lhs. */
++nrules;
previous_rule_end = grammar_end;
@@ -607,6 +600,23 @@ check_and_convert_grammar (void)
endtoken->user_token_number = 0;
}
+ /* Find the start symbol if no %start. */
+ if (!start_flag)
+ {
+ symbol_list *node;
+ for (node = grammar;
+ node != NULL && symbol_is_dummy (node->sym);
+ node = node->next)
+ {
+ for (node = node->next;
+ node != NULL && node->sym != NULL;
+ node = node->next)
+ ;
+ }
+ assert (node != NULL);
+ grammar_start_symbol_set (node->sym, node->sym->location);
+ }
+
/* Insert the initial rule, whose line is that of the first rule
(not that of the start symbol):
Index: src/symtab.c
===================================================================
RCS file: /sources/bison/bison/src/symtab.c,v
retrieving revision 1.77
diff -p -u -r1.77 symtab.c
--- src/symtab.c 18 Aug 2006 21:43:18 -0000 1.77
+++ src/symtab.c 20 Aug 2006 03:07:49 -0000
@@ -615,6 +615,11 @@ dummy_symbol_get (location loc)
return sym;
}
+bool
+symbol_is_dummy (const symbol *sym)
+{
+ return sym->tag[0] == '@';
+}
/*-------------------.
| Free the symbols. |
Index: src/symtab.h
===================================================================
RCS file: /sources/bison/bison/src/symtab.h,v
retrieving revision 1.63
diff -p -u -r1.63 symtab.h
--- src/symtab.h 29 Jul 2006 05:53:41 -0000 1.63
+++ src/symtab.h 20 Aug 2006 03:07:49 -0000
@@ -133,6 +133,9 @@ symbol *symbol_get (const char *key, loc
Its name cannot conflict with the user's names. */
symbol *dummy_symbol_get (location loc);
+/** Is this a dummy nonterminal? */
+bool symbol_is_dummy (const symbol *sym);
+
/** Declare the new symbol \c sym. Make it an alias of \c symval. */
void symbol_make_alias (symbol *sym, symbol *symval, location loc);
Index: tests/input.at
===================================================================
RCS file: /sources/bison/bison/tests/input.at,v
retrieving revision 1.53
diff -p -u -r1.53 input.at
--- tests/input.at 14 Aug 2006 20:51:33 -0000 1.53
+++ tests/input.at 20 Aug 2006 03:07:49 -0000
@@ -537,3 +537,24 @@ input.y:20.1: syntax error, unexpected e
]])
AT_CLEANUP
+
+
+## ------------------------- ##
+## %start after first rule. ##
+## ------------------------- ##
+
+AT_SETUP([%start after first rule])
+
+# Bison once complained that a %start after the first rule was a redeclaration
+# of the start symbol.
+
+AT_DATA([input.y],
+[[%%
+false_start: ;
+start: false_start ;
+%start start;
+]])
+
+AT_CHECK([bison -o input.c input.y])
+
+AT_CLEANUP
- FYI: fix %start after first rule,
Joel E. Denny <=