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Purity of yyerror etc.
From: |
Paul Eggert |
Subject: |
Purity of yyerror etc. |
Date: |
Fri, 29 Nov 2002 00:57:04 -0800 (PST) |
> From: Akim Demaille <address@hidden>
> Date: 04 Nov 2002 08:29:53 +0100
> | This syntax avoids the need for duplicating the declared identifier
> | ("ast" in this case), and it makes the %parse-param directive easier
> | to explain and read.
> Yes, that's sure. Well, if you really prefer the lighter syntax,
> let's go for it.
OK, I finally got around to it, by installing this patch.
As a side effect, this patch removes the "," token (since it's no
longer needed), and is compatible with the byacc behavior of treating
"," as white space. I am becoming more and more of a fan of being
compatible with Yacc, as I am being bitten by incompatibilities
in practice (the latest being with Mawk; the Mawk grammar isn't
acceptable to Bison, but that's a different matter).
2002-11-29 Paul Eggert <address@hidden>
%parse-param and %lex-param now take just one argument, the
declaration; the argument name is deduced from the declaration.
* doc/bison.texinfo (Parser Function, Pure Calling, Error
Reporting, Table of Symbols): Document this.
* src/parse-gram.y (add_param): New function.
(COMMA): Remove.
(declaration): Implement new rule for %parse-param and %lex-param.
* src/scan-gram.l: "," now elicits a warning, rather than being
a token; this is more compatible with byacc.
* tests/calc.at (Simple LALR Calculator): Adopt new convention.
Index: doc/bison.texinfo
===================================================================
RCS file: /cvsroot/bison/bison/doc/bison.texinfo,v
retrieving revision 1.86
diff -p -u -r1.86 bison.texinfo
--- doc/bison.texinfo 27 Nov 2002 18:32:12 -0000 1.86
+++ doc/bison.texinfo 29 Nov 2002 08:30:42 -0000
@@ -3847,19 +3847,20 @@ If you use a reentrant parser, you can o
parameter information to it in a reentrant way. To do so, use the
declaration @code{%parse-param}:
address@hidden {Directive} %parse-param @address@hidden@}, @address@hidden@}
address@hidden {Directive} %parse-param @address@hidden@}
@findex %parse-param
-Declare that @code{argument-name} is an additional @code{yyparse}
-argument. This argument is also passed to @code{yyerror}. The
address@hidden is used when declaring functions or
-prototypes.
+Declare that an argument declared by @code{argument-declaration} is an
+additional @code{yyparse} argument. This argument is also passed to
address@hidden The @var{argument-declaration} is used when declaring
+functions or prototypes. The last identifier in
address@hidden must be the argument name.
@end deffn
Here's an example. Write this in the parser:
@example
-%parse-param @{int address@hidden, @address@hidden
-%parse-param @{int address@hidden, @address@hidden
+%parse-param @{int address@hidden
+%parse-param @{int address@hidden
@end example
@noindent
@@ -4090,18 +4091,18 @@ If you wish to pass the additional param
@code{%lex-param} just like @code{%parse-param} (@pxref{Parser
Function}).
address@hidden {Directive} lex-param @address@hidden@}, @address@hidden@}
address@hidden {Directive} lex-param @address@hidden@}
@findex %lex-param
-Declare that @code{argument-name} is an additional @code{yylex}
-argument.
+Declare that @code{argument-declaration} is an additional @code{yylex}
+argument declaration.
@end deffn
For instance:
@example
-%parse-param @{int address@hidden, @address@hidden
-%lex-param @{int address@hidden, @address@hidden
-%parse-param @{int address@hidden, @address@hidden
+%parse-param @{int address@hidden
+%lex-param @{int address@hidden
+%parse-param @{int address@hidden
@end example
@noindent
@@ -4190,7 +4191,7 @@ void yyerror (const char *msg);
void yyerror (YYLTYPE *locp, const char *msg); /* GLR parsers. */
@end example
-If @samp{%parse-param @{int address@hidden, @address@hidden is used, then:
+If @samp{%parse-param @{int address@hidden is used, then:
@example
void yyerror (int *randomness, const char *msg); /* Yacc parsers. */
@@ -4207,10 +4208,10 @@ convention of @code{yylex} @emph{and} th
%locations
/* Pure yylex. */
%pure-parser
-%lex-param @{int address@hidden, @address@hidden
+%lex-param @{int address@hidden
/* Pure yyparse. */
-%parse-param @{int address@hidden, @address@hidden
-%parse-param @{int address@hidden, @address@hidden
+%parse-param @{int address@hidden
+%parse-param @{int address@hidden
@end example
@noindent
@@ -6498,7 +6499,7 @@ Bison declaration to assign left associa
@xref{Precedence Decl, ,Operator Precedence}.
@end deffn
address@hidden {Directive} %lex-param @address@hidden@}. @address@hidden"@}
address@hidden {Directive} %lex-param @address@hidden@}
Bison declaration to specifying an additional parameter that
@code{yylex} should accept. @xref{Pure Calling,, Calling Conventions
for Pure Parsers}.
@@ -6530,7 +6531,7 @@ Bison declaration to set the name of the
Summary}.
@end deffn
address@hidden {Directive} %parse-param @address@hidden@}, @address@hidden@}
address@hidden {Directive} %parse-param @address@hidden@}
Bison declaration to specifying an additional parameter that
@code{yyparse} should accept. @xref{Parser Function,, The Parser
Function @code{yyparse}}.
Index: src/parse-gram.y
===================================================================
RCS file: /cvsroot/bison/bison/src/parse-gram.y,v
retrieving revision 1.31
diff -p -u -r1.31 parse-gram.y
--- src/parse-gram.y 27 Nov 2002 18:33:18 -0000 1.31
+++ src/parse-gram.y 29 Nov 2002 08:30:43 -0000
@@ -67,6 +67,8 @@ do { \
print_token_value (File, Type, &Value)
static void print_token_value (FILE *file, int type, YYSTYPE const *value);
+static void add_param (char const *, char const *, location_t);
+
symbol_class current_class = unknown_sym;
struniq_t current_type = 0;
symbol_t *current_lhs;
@@ -141,7 +143,6 @@ braced_code_t current_braced_code = acti
%token EQUAL "="
%token SEMICOLON ";"
%token COLON ":"
-%token COMMA ","
%token PIPE "|"
%token ID "identifier"
%token PERCENT_PERCENT "%%"
@@ -184,20 +185,12 @@ declaration:
| "%expect" INT { expected_conflicts = $2; }
| "%file-prefix" "=" string_content { spec_file_prefix = $3; }
| "%glr-parser" { glr_parser = 1; }
-| "%lex-param" code_content "," code_content
- {
- muscle_pair_list_grow ("lex_param", $2, $4);
- scanner_last_string_free ();
- }
+| "%lex-param" code_content { add_param ("lex_param", $2, @2); }
| "%locations" { locations_flag = 1; }
| "%name-prefix" "=" string_content { spec_name_prefix = $3; }
| "%no-lines" { no_lines_flag = 1; }
| "%output" "=" string_content { spec_outfile = $3; }
-| "%parse-param" code_content "," code_content
- {
- muscle_pair_list_grow ("parse_param", $2, $4);
- scanner_last_string_free ();
- }
+| "%parse-param" code_content { add_param ("parse_param", $2, @2); }
| "%pure-parser" { pure_parser = 1; }
| "%skeleton" string_content { skeleton = $2; }
| "%token-table" { token_table_flag = 1; }
@@ -435,6 +428,44 @@ semi_colon.opt:
| ";"
;
%%
+static void
+add_param (char const *type, char const *decl, location_t loc)
+{
+ static char const alphanum[] =
+ "0123456789"
+ "abcdefghijklmnopqrstuvwxyz"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "_";
+ char const *alpha = alphanum + 10;
+ char const *name_start = NULL;
+ char const *p;
+
+ for (p = decl; *p; p++)
+ if ((p == decl || ! strchr (alphanum, p[-1])) && strchr (alpha, p[0]))
+ name_start = p;
+
+ if (! name_start)
+ complain_at (loc, _("missing identifier in parameter declaration"));
+ else
+ {
+ char *name;
+ size_t name_len;
+
+ for (name_len = 1;
+ name_start[name_len] && strchr (alphanum, name_start[name_len]);
+ name_len++)
+ continue;
+
+ name = xmalloc (name_len + 1);
+ memcpy (name, name_start, name_len);
+ name[name_len] = '\0';
+ muscle_pair_list_grow (type, decl, name);
+ free (name);
+ }
+
+ scanner_last_string_free ();
+}
+
/*------------------------------------------------------------------.
| When debugging the parser, display tokens' locations and values. |
`------------------------------------------------------------------*/
Index: src/scan-gram.l
===================================================================
RCS file: /cvsroot/bison/bison/src/scan-gram.l,v
retrieving revision 1.44
diff -p -u -r1.44 scan-gram.l
--- src/scan-gram.l 27 Nov 2002 18:34:14 -0000 1.44
+++ src/scan-gram.l 29 Nov 2002 08:30:43 -0000
@@ -266,10 +266,14 @@ splice (\\[ \f\t\v]*\n)*
"=" return EQUAL;
":" rule_length = 0; return COLON;
"|" rule_length = 0; return PIPE;
- "," return COMMA;
";" return SEMICOLON;
[ \f\n\t\v] STEP;
+
+ "," {
+ warn_at (*loc, _("stray `,' treated as white space"));
+ STEP;
+ }
{id} {
val->symbol = symbol_get (yytext, *loc);
Index: tests/calc.at
===================================================================
RCS file: /cvsroot/bison/bison/tests/calc.at,v
retrieving revision 1.47
diff -p -u -r1.47 calc.at
--- tests/calc.at 21 Nov 2002 05:28:09 -0000 1.47
+++ tests/calc.at 29 Nov 2002 08:30:43 -0000
@@ -562,7 +562,7 @@ AT_CHECK_CALC_LALR([%error-verbose %debu
AT_CHECK_CALC_LALR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc])
-AT_CHECK_CALC_LALR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc %parse-param {value_t *result}, {result}
%parse-param {int *count}, {count}])
+AT_CHECK_CALC_LALR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc %parse-param {value_t *result} %parse-param
{int *count}])
# ----------------------- #
@@ -597,4 +597,4 @@ AT_CHECK_CALC_GLR([%error-verbose %debug
AT_CHECK_CALC_GLR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc])
-AT_CHECK_CALC_GLR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc %parse-param {value_t *result}, {result}
%parse-param {int *count}, {count}])
+AT_CHECK_CALC_GLR([%pure-parser %error-verbose %debug %locations %defines
%name-prefix="calc" %verbose %yacc %parse-param {value_t *result} %parse-param
{int *count}])
- Purity of yyerror etc.,
Paul Eggert <=