Manual

60 Bison 2.3
See Section 8.2 [Tracing Your Parser], page 95.
%defines
[Directive]
Write a header file containing macro definitions for the token type names defined in
the grammar as well as a few other declarations. If the parser output file is named
‘name.c’ then this file is named ‘name.h’.
Unless YYSTYPE is already defined as a macro, the output header declares YYSTYPE.
Therefore, if you are using a %union (see Section 3.5.2 [More Than One Value Type],
page 46) with components that require other definitions, or if you have defined a
YYSTYPE macro (see Section 3.5.1 [Data Types of Semantic Values], page 46), you
need to arrange for these definitions to be propagated to all modules, e.g., by putting
them in a prerequisite header that is included both by your parser and by any other
module that needs YYSTYPE.
Unless your parser is pure, the output header declares yylval as an external variable.
See Section 3.7.10 [A Pure (Reentrant) Parser], page 58.
If you have also used locations, the output header declares YYLTYPE and yylloc
using a protocol similar to that of YYSTYPE and yylval. See Section 3.6 [Tracking
Locations], page 51.
This output file is normally essential if you wish to put the definition of yylex in a
separate source file, because yylex typically needs to be able to refer to the abovementioned
declarations and to the token type codes. See Section 4.2.2 [Semantic
Values of Tokens], page 65.
%destructor
[Directive]
Specify how the parser should reclaim the memory associated to discarded symbols.
See Section 3.7.7 [Freeing Discarded Symbols], page 57.
%file-prefix="prefix"
[Directive]
Specify a prefix to use for all Bison output file names. The names are chosen as if the
input file were named ‘prefix.y’.
%locations
[Directive]
Generate the code processing the locations (see Section 4.4 [Special Features for Use
in Actions], page 68). This mode is enabled as soon as the grammar uses the special
‘@n’ tokens, but if your grammar does not use it, using ‘%locations’ allows for more
accurate syntax error messages.
%name-prefix="prefix"
[Directive]
Rename the external symbols used in the parser so that they start with prefix instead
of ‘yy’. The precise list of symbols renamed in C parsers is yyparse, yylex, yyerror,
yynerrs, yylval, yychar, yydebug, and (if locations are used) yylloc. For example,
if you use ‘%name-prefix="c_"’, the names become c_parse, c_lex, and so on. In
C++ parsers, it is only the surrounding namespace which is named prefix instead of
‘yy’. See Section 3.8 [Multiple Parsers in the Same Program], page 62.
%no-parser
[Directive]
Do not include any C code in the parser file; generate tables only. The parser file
contains just #define directives and static variable declarations.