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Merge remote-tracking branch 'origin/maint'
* origin/maint: NEWS: spell check. api.prefix. Conflicts: data/c.m4 data/glr.cc data/lalr1.cc doc/bison.texi
This commit is contained in:
Akim Demaille
112
doc/bison.texi
112
doc/bison.texi
@@ -5452,6 +5452,20 @@ The parser namespace is @code{foo} and @code{yylex} is referenced as
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@c namespace
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@c ================================================== api.prefix
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@item api.prefix
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@findex %define api.prefix
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@itemize @bullet
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@item Language(s): All
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@item Purpose: Rename exported symbols
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@xref{Multiple Parsers, ,Multiple Parsers in the Same Program}.
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@item Accepted Values: String
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@item Default Value: @code{yy}
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@end itemize
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@c ================================================== api.pure
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@item api.pure
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@@ -5830,34 +5844,62 @@ of the standard Bison skeletons.
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@section Multiple Parsers in the Same Program
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Most programs that use Bison parse only one language and therefore contain
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only one Bison parser. But what if you want to parse more than one
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language with the same program? Then you need to avoid a name conflict
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between different definitions of @code{yyparse}, @code{yylval}, and so on.
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only one Bison parser. But what if you want to parse more than one language
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with the same program? Then you need to avoid name conflicts between
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different definitions of functions and variables such as @code{yyparse},
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@code{yylval}. To use different parsers from the same compilation unit, you
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also need to avoid conflicts on types and macros (e.g., @code{YYSTYPE})
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exported in the generated header.
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The easy way to do this is to use the option @samp{-p @var{prefix}}
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(@pxref{Invocation, ,Invoking Bison}). This renames the interface
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functions and variables of the Bison parser to start with @var{prefix}
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instead of @samp{yy}. You can use this to give each parser distinct
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names that do not conflict.
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The easy way to do this is to define the @code{%define} variable
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@code{api.prefix} (possibly using the option
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@samp{-Dapi.prefix=@var{prefix}}, see @ref{Invocation, ,Invoking Bison}).
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This renames the interface functions and variables of the Bison parser to
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start with @var{prefix} instead of @samp{yy}, and all the macros to start by
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@var{PREFIX} (i.e., @var{prefix} upper cased) instead of @samp{YY}. You can
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use this to give each parser distinct names that do not conflict.
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The precise list of symbols renamed is @code{yyparse}, @code{yylex},
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@code{yyerror}, @code{yynerrs}, @code{yylval}, @code{yylloc},
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@code{yychar} and @code{yydebug}. If you use a push parser,
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@code{yypush_parse}, @code{yypull_parse}, @code{yypstate},
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@code{yypstate_new} and @code{yypstate_delete} will also be renamed.
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For example, if you use @samp{-p c}, the names become @code{cparse},
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@code{clex}, and so on.
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The renamed symbols include @code{yyparse}, @code{yylex}, @code{yyerror},
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@code{yynerrs}, @code{yylval}, @code{yylloc}, @code{yychar} and
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@code{yydebug}. If you use a push parser, @code{yypush_parse},
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@code{yypull_parse}, @code{yypstate}, @code{yypstate_new} and
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@code{yypstate_delete} will also be renamed. The renamed macros include
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@code{YYSTYPE}, @code{YYSTYPE_IS_TRIVIAL}, @code{YYSTYPE_IS_DECLARED},
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@code{YYLTYPE}, @code{YYLTYPE_IS_TRIVIAL}, and @code{YYLTYPE_IS_DECLARED}.
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@strong{All the other variables and macros associated with Bison are not
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renamed.} These others are not global; there is no conflict if the same
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name is used in different parsers. For example, @code{YYSTYPE} is not
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renamed, but defining this in different ways in different parsers causes
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no trouble (@pxref{Value Type, ,Data Types of Semantic Values}).
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For example, if you use @samp{%define api.prefix c}, the names become
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@code{cparse}, @code{clex}, @dots{}, @code{CSTYPE}, @code{CLTYPE}, and so
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on.
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The @samp{-p} option works by adding macro definitions to the
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beginning of the parser implementation file, defining @code{yyparse}
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as @code{@var{prefix}parse}, and so on. This effectively substitutes
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one name for the other in the entire parser implementation file.
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The @code{%define} variable @code{api.prefix} works in two different ways.
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In the implementation file, it works by adding macro definitions to the
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beginning of the parser implementation file, defining @code{yyparse} as
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@code{@var{prefix}parse}, and so on:
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@example
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#define YYSTYPE CTYPE
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#define yyparse cparse
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#define yylval clval
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...
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YYSTYPE yylval;
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int yyparse (void);
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@end example
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This effectively substitutes one name for the other in the entire parser
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implementation file, thus the ``original'' names (@code{yylex},
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@code{YYSTYPE}, @dots{}) are also usable in the parser implementation file.
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However, in the parser header file, the symbols are defined renamed, for
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instance:
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@example
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extern CSTYPE clval;
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int cparse (void);
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@end example
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Previously, a similar feature was provided by the obsoleted directive
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@code{%name-prefix} (@pxref{Table of Symbols, ,Bison Symbols}) and option
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@code{--name-prefix} (@pxref{Bison Options}).
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@node Interface
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@chapter Parser C-Language Interface
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@@ -9238,8 +9280,9 @@ Pretend that @code{%locations} was specified. @xref{Decl Summary}.
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@item -p @var{prefix}
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@itemx --name-prefix=@var{prefix}
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Pretend that @code{%name-prefix "@var{prefix}"} was specified.
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@xref{Decl Summary}.
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Pretend that @code{%name-prefix "@var{prefix}"} was specified (@pxref{Decl
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Summary}). Obsoleted by @code{-Dapi.prefix=@var{prefix}}. @xref{Multiple
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Parsers, ,Multiple Parsers in the Same Program}.
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@item -l
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@itemx --no-lines
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@@ -11701,9 +11744,24 @@ function is applied to the two semantic values to get a single result.
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@end deffn
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@deffn {Directive} %name-prefix "@var{prefix}"
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Bison declaration to rename the external symbols. @xref{Decl Summary}.
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Obsoleted by the @code{%define} variable @code{api.prefix} (@pxref{Multiple
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Parsers, ,Multiple Parsers in the Same Program}).
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Rename the external symbols (variables and functions) used in the parser so
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that they start with @var{prefix} instead of @samp{yy}. Contrary to
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@code{api.prefix}, do no rename types and macros.
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The precise list of symbols renamed in C parsers is @code{yyparse},
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@code{yylex}, @code{yyerror}, @code{yynerrs}, @code{yylval}, @code{yychar},
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@code{yydebug}, and (if locations are used) @code{yylloc}. If you use a
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push parser, @code{yypush_parse}, @code{yypull_parse}, @code{yypstate},
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@code{yypstate_new} and @code{yypstate_delete} will also be renamed. For
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example, if you use @samp{%name-prefix "c_"}, the names become
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@code{c_parse}, @code{c_lex}, and so on. For C++ parsers, see the
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@code{%define namespace} documentation in this section.
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@end deffn
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@ifset defaultprec
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@deffn {Directive} %no-default-prec
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Do not assign a precedence to rules that lack an explicit @samp{%prec}
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