X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e6ae99fe756493288df062299dff09de4f7a8e52..db8ab2be3337ef87629b761078ebc46a01e7f876:/doc/bison.texi?ds=sidebyside diff --git a/doc/bison.texi b/doc/bison.texi index 6346bf03..75e80183 100644 --- a/doc/bison.texi +++ b/doc/bison.texi @@ -110,7 +110,7 @@ Reference sections: * Glossary:: Basic concepts are explained. * Copying This Manual:: License for copying this manual. * Bibliography:: Publications cited in this manual. -* Index:: Cross-references to the text. +* Index of Terms:: Cross-references to the text. @detailmenu --- The Detailed Node Listing --- @@ -327,6 +327,7 @@ C++ Location Values * C++ position:: One point in the source file * C++ location:: Two points in the source file +* User Defined Location Type:: Required interface for locations A Complete C++ Example @@ -4552,9 +4553,9 @@ code. @deffn {Directive} %initial-action @{ @var{code} @} @findex %initial-action Declare that the braced @var{code} must be invoked before parsing each time -@code{yyparse} is called. The @var{code} may use @code{$$} and -@code{@@$} --- initial value and location of the lookahead --- and the -@code{%parse-param}. +@code{yyparse} is called. The @var{code} may use @code{$$} (or +@code{$<@var{tag}>$}) and @code{@@$} --- initial value and location of the +lookahead --- and the @code{%parse-param}. @end deffn For instance, if your locations use a file name, you may use @@ -4592,11 +4593,11 @@ symbol is automatically discarded. @deffn {Directive} %destructor @{ @var{code} @} @var{symbols} @findex %destructor Invoke the braced @var{code} whenever the parser discards one of the -@var{symbols}. -Within @var{code}, @code{$$} designates the semantic value associated -with the discarded symbol, and @code{@@$} designates its location. -The additional parser parameters are also available (@pxref{Parser Function, , -The Parser Function @code{yyparse}}). +@var{symbols}. Within @var{code}, @code{$$} (or @code{$<@var{tag}>$}) +designates the semantic value associated with the discarded symbol, and +@code{@@$} designates its location. The additional parser parameters are +also available (@pxref{Parser Function, , The Parser Function +@code{yyparse}}). When a symbol is listed among @var{symbols}, its @code{%destructor} is called a per-symbol @code{%destructor}. @@ -4701,6 +4702,10 @@ incoming terminals during the second phase of error recovery, the current lookahead and the entire stack (except the current right-hand side symbols) when the parser returns immediately, and @item +the current lookahead and the entire stack (including the current right-hand +side symbols) when the C++ parser (@file{lalr1.cc}) catches an exception in +@code{parse}, +@item the start symbol, when the parser succeeds. @end itemize @@ -4734,10 +4739,11 @@ Decl, , Freeing Discarded Symbols}). @c This is the same text as for %destructor. Invoke the braced @var{code} whenever the parser displays one of the @var{symbols}. Within @var{code}, @code{yyoutput} denotes the output stream -(a @code{FILE*} in C, and an @code{std::ostream&} in C++), -@code{$$} designates the semantic value associated with the symbol, and -@code{@@$} its location. The additional parser parameters are also -available (@pxref{Parser Function, , The Parser Function @code{yyparse}}). +(a @code{FILE*} in C, and an @code{std::ostream&} in C++), @code{$$} (or +@code{$<@var{tag}>$}) designates the semantic value associated with the +symbol, and @code{@@$} its location. The additional parser parameters are +also available (@pxref{Parser Function, , The Parser Function +@code{yyparse}}). The @var{symbols} are defined as for @code{%destructor} (@pxref{Destructor Decl, , Freeing Discarded Symbols}.): they can be per-type (e.g., @@ -5075,7 +5081,7 @@ default location or at the location specified by @var{qualifier}. @deffn {Directive} %debug In the parser implementation file, define the macro @code{YYDEBUG} (or -@code{@var{prefix}DEBUG} with @samp{%define api.prefix @var{prefix}}), see +@code{@var{prefix}DEBUG} with @samp{%define api.prefix @var{prefix}}, see @ref{Multiple Parsers, ,Multiple Parsers in the Same Program}) to 1 if it is not already defined, so that the debugging facilities are compiled. @xref{Tracing, ,Tracing Your Parser}. @@ -5123,6 +5129,23 @@ Values, ,Semantic Values of Tokens}. If you have declared @code{%code requires} or @code{%code provides}, the output header also contains their code. @xref{%code Summary}. + +@cindex Header guard +The generated header is protected against multiple inclusions with a C +preprocessor guard: @samp{YY_@var{PREFIX}_@var{FILE}_INCLUDED}, where +@var{PREFIX} and @var{FILE} are the prefix (@pxref{Multiple Parsers, +,Multiple Parsers in the Same Program}) and generated file name turned +uppercase, with each series of non alphanumerical characters converted to a +single underscore. + +For instance with @samp{%define api.prefix "calc"} and @samp{%defines +"lib/parse.h"}, the header will be guarded as follows. +@example +#ifndef YY_CALC_LIB_PARSE_H_INCLUDED +# define YY_CALC_LIB_PARSE_H_INCLUDED +... +#endif /* ! YY_CALC_LIB_PARSE_H_INCLUDED */ +@end example @end deffn @deffn {Directive} %defines @var{defines-file} @@ -5303,6 +5326,23 @@ Unaccepted @var{variable}s produce an error. Some of the accepted @var{variable}s are: @itemize @bullet +@c ================================================== api.location.type +@item @code{api.location.type} +@findex %define api.location.type + +@itemize @bullet +@item Language(s): C++ + +@item Purpose: Define the location type. +@xref{User Defined Location Type}. + +@item Accepted Values: String + +@item Default Value: none + +@item History: introduced in Bison 2.7 +@end itemize + @c ================================================== api.prefix @item @code{api.prefix} @findex %define api.prefix @@ -5310,7 +5350,7 @@ Some of the accepted @var{variable}s are: @itemize @bullet @item Language(s): All -@item Purpose: Rename exported symbols +@item Purpose: Rename exported symbols. @xref{Multiple Parsers, ,Multiple Parsers in the Same Program}. @item Accepted Values: String @@ -8501,8 +8541,8 @@ Prologue}). If the @code{%define} variable @code{api.prefix} is used (@pxref{Multiple Parsers, ,Multiple Parsers in the Same Program}), for instance @samp{%define api.prefix x}, then if @code{CDEBUG} is defined, its value controls the -tracing feature (enabled iff nonzero); otherwise tracing is enabled iff -@code{YYDEBUG} is nonzero. +tracing feature (enabled if and only if nonzero); otherwise tracing is +enabled if and only if @code{YYDEBUG} is nonzero. @item the option @option{-t} (POSIX Yacc compliant) @itemx the option @option{--debug} (Bison extension) @@ -9054,13 +9094,23 @@ separated list of @var{things} among: Description of the grammar, conflicts (resolved and unresolved), and parser's automaton. +@item itemset +Implies @code{state} and augments the description of the automaton with +the full set of items for each state, instead of its core only. + @item lookahead Implies @code{state} and augments the description of the automaton with each rule's lookahead set. -@item itemset -Implies @code{state} and augments the description of the automaton with -the full set of items for each state, instead of its core only. +@item solved +Implies @code{state}. Explain how conflicts were solved thanks to +precedence and associativity directives. + +@item all +Enable all the items. + +@item none +Do not generate the report. @end table @item --report-file=@var{file} @@ -9178,8 +9228,9 @@ generated in the following files: @table @file @item position.hh @itemx location.hh -The definition of the classes @code{position} and @code{location}, -used for location tracking. @xref{C++ Location Values}. +The definition of the classes @code{position} and @code{location}, used for +location tracking. These files are not generated if the @code{%define} +variable @code{api.location.type} is defined. @xref{C++ Location Values}. @item stack.hh An auxiliary class @code{stack} used by the parser. @@ -9235,18 +9286,22 @@ Symbols}. @c - %define filename_type "const symbol::Symbol" When the directive @code{%locations} is used, the C++ parser supports -location tracking, see @ref{Tracking Locations}. Two auxiliary classes -define a @code{position}, a single point in a file, and a @code{location}, a -range composed of a pair of @code{position}s (possibly spanning several -files). +location tracking, see @ref{Tracking Locations}. + +By default, two auxiliary classes define a @code{position}, a single point +in a file, and a @code{location}, a range composed of a pair of +@code{position}s (possibly spanning several files). But if the +@code{%define} variable @code{api.location.type} is defined, then these +classes will not be generated, and the user defined type will be used. @tindex uint In this section @code{uint} is an abbreviation for @code{unsigned int}: in genuine code only the latter is used. @menu -* C++ position:: One point in the source file -* C++ location:: Two points in the source file +* C++ position:: One point in the source file +* C++ location:: Two points in the source file +* User Defined Location Type:: Required interface for locations @end menu @node C++ position @@ -9350,6 +9405,63 @@ Report @var{p} on @var{o}, taking care of special cases such as: no @code{filename} defined, or equal filename/line or column. @end deftypefun +@node User Defined Location Type +@subsubsection User Defined Location Type +@findex %define api.location.type + +Instead of using the built-in types you may use the @code{%define} variable +@code{api.location.type} to specify your own type: + +@example +%define api.location.type @var{LocationType} +@end example + +The requirements over your @var{LocationType} are: +@itemize +@item +it must be copyable; + +@item +in order to compute the (default) value of @code{@@$} in a reduction, the +parser basically runs +@example +@@$.begin = @@$1.begin; +@@$.end = @@$@var{N}.end; // The location of last right-hand side symbol. +@end example +@noindent +so there must be copyable @code{begin} and @code{end} members; + +@item +alternatively you may redefine the computation of the default location, in +which case these members are not required (@pxref{Location Default Action}); + +@item +if traces are enabled, then there must exist an @samp{std::ostream& + operator<< (std::ostream& o, const @var{LocationType}& s)} function. +@end itemize + +@sp 1 + +In programs with several C++ parsers, you may also use the @code{%define} +variable @code{api.location.type} to share a common set of built-in +definitions for @code{position} and @code{location}. For instance, one +parser @file{master/parser.yy} might use: + +@example +%defines +%locations +%define namespace "master::" +@end example + +@noindent +to generate the @file{master/position.hh} and @file{master/location.hh} +files, reused by other parsers as follows: + +@example +%define location_type "master::location" +%code requires @{ #include @} +@end example + @node C++ Parser Interface @subsection C++ Parser Interface @c - define parser_class_name @@ -9387,6 +9499,11 @@ Build a new parser object. There are no arguments by default, unless @deftypemethod {parser} {int} parse () Run the syntactic analysis, and return 0 on success, 1 otherwise. + +@cindex exceptions +The whole function is wrapped in a @code{try}/@code{catch} block, so that +when an exception is thrown, the @code{%destructor}s are called to release +the lookahead symbol, and the symbols pushed on the stack. @end deftypemethod @deftypemethod {parser} {std::ostream&} debug_stream () @@ -11704,8 +11821,8 @@ London, Department of Computer Science, TR-00-12 (December 2000). @uref{http://www.cs.rhul.ac.uk/research/languages/publications/tomita_style_1.ps} @end table -@node Index -@unnumbered Index +@node Index of Terms +@unnumbered Index of Terms @printindex cp @@ -11760,10 +11877,11 @@ London, Department of Computer Science, TR-00-12 (December 2000). @c LocalWords: toString deftypeivar deftypeivarx deftypeop YYParser strictfp @c LocalWords: superclasses boolean getErrorVerbose setErrorVerbose deftypecv @c LocalWords: getDebugStream setDebugStream getDebugLevel setDebugLevel url -@c LocalWords: bisonVersion deftypecvx bisonSkeleton getStartPos getEndPos +@c LocalWords: bisonVersion deftypecvx bisonSkeleton getStartPos getEndPos uint @c LocalWords: getLVal defvar deftypefn deftypefnx gotos msgfmt Corbett LALR's -@c LocalWords: subdirectory Solaris nonassociativity perror schemas Malloy -@c LocalWords: Scannerless ispell american +@c LocalWords: subdirectory Solaris nonassociativity perror schemas Malloy ints +@c LocalWords: Scannerless ispell american ChangeLog smallexample CSTYPE CLTYPE +@c LocalWords: clval CDEBUG cdebug deftypeopx yyterminate @c Local Variables: @c ispell-dictionary: "american"