mirror of
https://git.savannah.gnu.org/git/bison.git
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doc: various minor improvements and fixes
* doc/figs/example.dot, doc/figs/example.y: New. * doc/bison.texi: Prefer "token" to TOKEN. Use @group where appropriate. Adjust with style changes in the output (State 0, not state 0). Fix some @ref that were missing the third argument. Fix some incorrect line numbers. Use "nonterminal", not "non-terminal". Fix overfull and underfull TeX hboxes. Put the comments in the index. Remove duplicate index entries. Fuse glossary entries where appropriate. (Understanding): Improve the continuity between sections. Use example.dot to show the whole graph. * doc/Makefile.am: Adjust.
This commit is contained in:
Akim Demaille
@@ -96,13 +96,14 @@ PREPATH = $(top_builddir)/src
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nodist_man_MANS = yacc.1
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## ----------------------------- ##
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## Graphviz examples generation. ##
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## ----------------------------- ##
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## ------------------------------ ##
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## Graphviz examples generation. ##
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## ------------------------------ ##
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CLEANDIRS += figs
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FIGS_DOT = figs/example-reduce.dot figs/example-shift.dot
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FIGS_DOT = figs/example.dot figs/example-reduce.dot figs/example-shift.dot
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EXTRA_DIST += \
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figs/example.y \
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$(FIGS_DOT) \
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$(FIGS_DOT:.dot=.eps) $(FIGS_DOT:.dot=.pdf) $(FIGS_DOT:.dot=.png)
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SUFFIXES += .dot .eps .pdf .png
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228
doc/bison.texi
228
doc/bison.texi
@@ -2722,6 +2722,9 @@ The Bison grammar file conventionally has a name ending in @samp{.y}.
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@node Grammar Outline
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@section Outline of a Bison Grammar
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@cindex comment
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@findex // @dots{}
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@findex /* @dots{} */
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A Bison grammar file has four main sections, shown here with the
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appropriate delimiters:
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@@ -2741,8 +2744,8 @@ appropriate delimiters:
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@end example
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Comments enclosed in @samp{/* @dots{} */} may appear in any of the sections.
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As a GNU extension, @samp{//} introduces a comment that
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continues until end of line.
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As a GNU extension, @samp{//} introduces a comment that continues until end
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of line.
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@menu
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* Prologue:: Syntax and usage of the prologue.
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@@ -3768,10 +3771,16 @@ remove it afterward. Here is how it is done:
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@example
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@group
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stmt:
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LET '(' var ')'
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@{ $<context>$ = push_context (); declare_variable ($3); @}
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"let" '(' var ')'
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@{
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$<context>$ = push_context ();
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declare_variable ($3);
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@}
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stmt
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@{ $$ = $6; pop_context ($<context>5); @}
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@{
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$$ = $6;
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pop_context ($<context>5);
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@}
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@end group
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@end example
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@@ -3821,7 +3830,7 @@ stmt:
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@};
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let:
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LET '(' var ')'
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"let" '(' var ')'
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@{
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$$ = push_context ();
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declare_variable ($3);
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@@ -5389,8 +5398,8 @@ I.e., if @samp{%locations %define api.pure} is passed then the prototypes for
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@code{yyerror} are:
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@example
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void yyerror (char const *msg); /* Yacc parsers. */
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void yyerror (YYLTYPE *locp, char const *msg); /* GLR parsers. */
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void yyerror (char const *msg); // Yacc parsers.
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void yyerror (YYLTYPE *locp, char const *msg); // GLR parsers.
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@end example
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But if @samp{%locations %define api.pure %parse-param @{int *nastiness@}} is
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@@ -6386,7 +6395,6 @@ Actions}).
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@end deffn
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@deffn {Value} @@$
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@findex @@$
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Acts like a structure variable containing information on the textual
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location of the grouping made by the current rule. @xref{Tracking
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Locations}.
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@@ -6445,7 +6453,7 @@ GNU Automake.
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@item
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@cindex bison-i18n.m4
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Into the directory containing the GNU Autoconf macros used
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by the package---often called @file{m4}---copy the
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by the package ---often called @file{m4}--- copy the
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@file{bison-i18n.m4} file installed by Bison under
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@samp{share/aclocal/bison-i18n.m4} in Bison's installation directory.
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For example:
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@@ -8191,8 +8199,26 @@ clear the flag.
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Developing a parser can be a challenge, especially if you don't understand
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the algorithm (@pxref{Algorithm, ,The Bison Parser Algorithm}). This
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chapter explains how to generate and read the detailed description of the
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automaton, and how to enable and understand the parser run-time traces.
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chapter explains how understand and debug a parser.
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The first sections focus on the static part of the parser: its structure.
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They explain how to generate and read the detailed description of the
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automaton. There are several formats available:
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@itemize @minus
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@item
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as text, see @ref{Understanding, , Understanding Your Parser};
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@item
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as a graph, see @ref{Graphviz,, Visualizing Your Parser};
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@item
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or as a markup report that can be turned, for instance, into HTML, see
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@ref{Xml,, Visualizing your parser in multiple formats}.
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@end itemize
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The last section focuses on the dynamic part of the parser: how to enable
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and understand the parser run-time traces (@pxref{Tracing, ,Tracing Your
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Parser}).
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@menu
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* Understanding:: Understanding the structure of your parser.
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@@ -8207,8 +8233,7 @@ automaton, and how to enable and understand the parser run-time traces.
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As documented elsewhere (@pxref{Algorithm, ,The Bison Parser Algorithm})
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Bison parsers are @dfn{shift/reduce automata}. In some cases (much more
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frequent than one would hope), looking at this automaton is required to
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tune or simply fix a parser. Bison provides two different
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representation of it, either textually or graphically (as a DOT file).
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tune or simply fix a parser.
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The textual file is generated when the options @option{--report} or
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@option{--verbose} are specified, see @ref{Invocation, , Invoking
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@@ -8222,9 +8247,12 @@ The following grammar file, @file{calc.y}, will be used in the sequel:
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@example
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%token NUM STR
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@group
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%left '+' '-'
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%left '*'
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@end group
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%%
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@group
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exp:
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exp '+' exp
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| exp '-' exp
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@@ -8232,6 +8260,7 @@ exp:
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| exp '/' exp
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| NUM
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;
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@end group
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useless: STR;
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%%
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@end example
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@@ -8241,8 +8270,8 @@ useless: STR;
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@example
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calc.y: warning: 1 nonterminal useless in grammar
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calc.y: warning: 1 rule useless in grammar
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calc.y:11.1-7: warning: nonterminal useless in grammar: useless
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calc.y:11.10-12: warning: rule useless in grammar: useless: STR
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calc.y:12.1-7: warning: nonterminal useless in grammar: useless
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calc.y:12.10-12: warning: rule useless in grammar: useless: STR
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calc.y: conflicts: 7 shift/reduce
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@end example
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@@ -8336,7 +8365,7 @@ item is a production rule together with a point (@samp{.}) marking
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the location of the input cursor.
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@example
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state 0
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State 0
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0 $accept: . exp $end
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@@ -8366,7 +8395,7 @@ you want to see more detail you can invoke @command{bison} with
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@option{--report=itemset} to list the derived items as well:
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@example
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state 0
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State 0
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0 $accept: . exp $end
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1 exp: . exp '+' exp
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@@ -8384,7 +8413,7 @@ state 0
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In the state 1@dots{}
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@example
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state 1
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State 1
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5 exp: NUM .
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@@ -8394,11 +8423,11 @@ state 1
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@noindent
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the rule 5, @samp{exp: NUM;}, is completed. Whatever the lookahead token
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(@samp{$default}), the parser will reduce it. If it was coming from
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state 0, then, after this reduction it will return to state 0, and will
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State 0, then, after this reduction it will return to state 0, and will
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jump to state 2 (@samp{exp: go to state 2}).
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@example
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state 2
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State 2
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0 $accept: exp . $end
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1 exp: exp . '+' exp
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@@ -8426,7 +8455,7 @@ The state 3 is named the @dfn{final state}, or the @dfn{accepting
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state}:
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@example
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state 3
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State 3
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0 $accept: exp $end .
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@@ -8441,7 +8470,7 @@ The interpretation of states 4 to 7 is straightforward, and is left to
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the reader.
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@example
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state 4
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State 4
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1 exp: exp '+' . exp
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@@ -8450,7 +8479,7 @@ state 4
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exp go to state 8
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state 5
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State 5
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2 exp: exp '-' . exp
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@@ -8459,7 +8488,7 @@ state 5
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exp go to state 9
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state 6
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State 6
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3 exp: exp '*' . exp
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@@ -8468,7 +8497,7 @@ state 6
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exp go to state 10
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state 7
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State 7
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4 exp: exp '/' . exp
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@@ -8481,7 +8510,7 @@ As was announced in beginning of the report, @samp{State 8 conflicts:
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1 shift/reduce}:
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@example
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state 8
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State 8
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1 exp: exp . '+' exp
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1 | exp '+' exp .
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@@ -8524,7 +8553,7 @@ with some set of possible lookahead tokens. When run with
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@option{--report=lookahead}, Bison specifies these lookahead tokens:
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@example
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state 8
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State 8
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1 exp: exp . '+' exp
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1 | exp '+' exp . [$end, '+', '-', '/']
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@@ -8556,7 +8585,7 @@ The remaining states are similar:
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@example
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@group
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state 9
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State 9
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1 exp: exp . '+' exp
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2 | exp . '-' exp
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@@ -8572,7 +8601,7 @@ state 9
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@end group
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@group
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state 10
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State 10
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1 exp: exp . '+' exp
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2 | exp . '-' exp
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@@ -8587,7 +8616,7 @@ state 10
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@end group
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@group
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state 11
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State 11
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1 exp: exp . '+' exp
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2 | exp . '-' exp
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@@ -8610,12 +8639,11 @@ state 11
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@noindent
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Observe that state 11 contains conflicts not only due to the lack of
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precedence of @samp{/} with respect to @samp{+}, @samp{-}, and
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@samp{*}, but also because the
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associativity of @samp{/} is not specified.
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precedence of @samp{/} with respect to @samp{+}, @samp{-}, and @samp{*}, but
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also because the associativity of @samp{/} is not specified.
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Note that Bison may also produce an HTML version of this output, via an XML
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file and XSLT processing (@pxref{Xml}).
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Bison may also produce an HTML version of this output, via an XML file and
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XSLT processing (@pxref{Xml,,Visualizing your parser in multiple formats}).
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@c ================================================= Graphical Representation
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@@ -8635,7 +8663,10 @@ This file is generated when the @option{--graph} option is specified
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(@pxref{Invocation, , Invoking Bison}). Its name is made by removing
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@samp{.tab.c} or @samp{.c} from the parser implementation file name, and
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adding @samp{.dot} instead. If the grammar file is @file{foo.y}, the
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Graphviz output file is called @file{foo.dot}.
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Graphviz output file is called @file{foo.dot}. A DOT file may also be
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produced via an XML file and XSLT processing (@pxref{Xml,,Visualizing your
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parser in multiple formats}).
|
||||
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||||
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The following grammar file, @file{rr.y}, will be used in the sequel:
|
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||||
@@ -8648,10 +8679,20 @@ b: "0";
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@end group
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@end example
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The graphical output is very similar to the textual one, and as such it is
|
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easier understood by making direct comparisons between them. See
|
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@ref{Debugging, , Debugging Your Parser} for a detailled analysis of the
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textual report.
|
||||
The graphical output
|
||||
@ifnotinfo
|
||||
(see @ref{fig:graph})
|
||||
@end ifnotinfo
|
||||
is very similar to the textual one, and as such it is easier understood by
|
||||
making direct comparisons between them. @xref{Debugging, , Debugging Your
|
||||
Parser}, for a detailled analysis of the textual report.
|
||||
|
||||
@ifnotinfo
|
||||
@float Figure,fig:graph
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@image{figs/example, 430pt}
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||||
@caption{A graphical rendering of the parser.}
|
||||
@end float
|
||||
@end ifnotinfo
|
||||
|
||||
@subheading Graphical Representation of States
|
||||
|
||||
@@ -8676,7 +8717,7 @@ shift. The following describes a reduction in the @file{rr.output} file:
|
||||
|
||||
@example
|
||||
@group
|
||||
state 3
|
||||
State 3
|
||||
|
||||
1 exp: a . ";"
|
||||
|
||||
@@ -8697,7 +8738,7 @@ action for the given state, there is no such label.
|
||||
|
||||
This is how reductions are represented in the verbose file @file{rr.output}:
|
||||
@example
|
||||
state 1
|
||||
State 1
|
||||
|
||||
3 a: "0" . [";"]
|
||||
4 b: "0" . ["."]
|
||||
@@ -8716,17 +8757,14 @@ reduction, see @ref{Shift/Reduce, , Shift/Reduce Conflicts}. Discarded actions
|
||||
are distinguished by a red filling color on these nodes, just like how they are
|
||||
reported between square brackets in the verbose file.
|
||||
|
||||
The reduction corresponding to the rule number 0 is the acceptation state. It
|
||||
is shown as a blue diamond, labelled "Acc".
|
||||
The reduction corresponding to the rule number 0 is the acceptation
|
||||
state. It is shown as a blue diamond, labelled ``Acc''.
|
||||
|
||||
@subheading Graphical representation of go tos
|
||||
|
||||
The @samp{go to} jump transitions are represented as dotted lines bearing
|
||||
the name of the rule being jumped to.
|
||||
|
||||
Note that a DOT file may also be produced via an XML file and XSLT
|
||||
processing (@pxref{Xml}).
|
||||
|
||||
@c ================================================= XML
|
||||
|
||||
@node Xml
|
||||
@@ -8734,8 +8772,10 @@ processing (@pxref{Xml}).
|
||||
@cindex xml
|
||||
|
||||
Bison supports two major report formats: textual output
|
||||
(@pxref{Understanding}) when invoked with option @option{--verbose}, and DOT
|
||||
(@pxref{Graphviz}) when invoked with option @option{--graph}. However,
|
||||
(@pxref{Understanding, ,Understanding Your Parser}) when invoked
|
||||
with option @option{--verbose}, and DOT
|
||||
(@pxref{Graphviz,, Visualizing Your Parser}) when invoked with
|
||||
option @option{--graph}. However,
|
||||
another alternative is to output an XML file that may then be, with
|
||||
@command{xsltproc}, rendered as either a raw text format equivalent to the
|
||||
verbose file, or as an HTML version of the same file, with clickable
|
||||
@@ -8743,7 +8783,7 @@ transitions, or even as a DOT. The @file{.output} and DOT files obtained via
|
||||
XSLT have no difference whatsoever with those obtained by invoking
|
||||
@command{bison} with options @option{--verbose} or @option{--graph}.
|
||||
|
||||
The textual file is generated when the options @option{-x} or
|
||||
The XML file is generated when the options @option{-x} or
|
||||
@option{--xml[=FILE]} are specified, see @ref{Invocation,,Invoking Bison}.
|
||||
If not specified, its name is made by removing @samp{.tab.c} or @samp{.c}
|
||||
from the parser implementation file name, and adding @samp{.xml} instead.
|
||||
@@ -8757,19 +8797,19 @@ files to apply to the XML file. Their names are non-ambiguous:
|
||||
@item xml2dot.xsl
|
||||
Used to output a copy of the DOT visualization of the automaton.
|
||||
@item xml2text.xsl
|
||||
Used to output a copy of the .output file.
|
||||
Used to output a copy of the @samp{.output} file.
|
||||
@item xml2xhtml.xsl
|
||||
Used to output an xhtml enhancement of the .output file.
|
||||
Used to output an xhtml enhancement of the @samp{.output} file.
|
||||
@end table
|
||||
|
||||
Sample usage (requires @code{xsltproc}):
|
||||
Sample usage (requires @command{xsltproc}):
|
||||
@example
|
||||
$ bison -x input.y
|
||||
$ bison -x gr.y
|
||||
@group
|
||||
$ bison --print-datadir
|
||||
/usr/local/share/bison
|
||||
@end group
|
||||
$ xsltproc /usr/local/share/bison/xslt/xml2xhtml.xsl input.xml > input.html
|
||||
$ xsltproc /usr/local/share/bison/xslt/xml2xhtml.xsl gr.xml >gr.html
|
||||
@end example
|
||||
|
||||
@c ================================================= Tracing
|
||||
@@ -8960,7 +9000,7 @@ Entering state 24
|
||||
|
||||
@noindent
|
||||
The previous reduction demonstrates the @code{%printer} directive for
|
||||
@code{<val>}: both the token @code{NUM} and the resulting non-terminal
|
||||
@code{<val>}: both the token @code{NUM} and the resulting nonterminal
|
||||
@code{exp} have @samp{1} as value.
|
||||
|
||||
@example
|
||||
@@ -9250,7 +9290,7 @@ Show caret errors, in a manner similar to GCC's
|
||||
@option{-fdiagnostics-show-caret}, or Clang's @option{-fcaret-diagnotics}. The
|
||||
location provided with the message is used to quote the corresponding line of
|
||||
the source file, underlining the important part of it with carets (^). Here is
|
||||
an example, using the following file @file{input.y}:
|
||||
an example, using the following file @file{in.y}:
|
||||
|
||||
@example
|
||||
%type <ival> exp
|
||||
@@ -9262,27 +9302,27 @@ When invoked with @option{-fcaret}, Bison will report:
|
||||
|
||||
@example
|
||||
@group
|
||||
input.y:3.20-23: error: ambiguous reference: '$exp'
|
||||
in.y:3.20-23: error: ambiguous reference: '$exp'
|
||||
exp: exp '+' exp @{ $exp = $1 + $2; @};
|
||||
^^^^
|
||||
@end group
|
||||
@group
|
||||
input.y:3.1-3: refers to: $exp at $$
|
||||
in.y:3.1-3: refers to: $exp at $$
|
||||
exp: exp '+' exp @{ $exp = $1 + $2; @};
|
||||
^^^
|
||||
@end group
|
||||
@group
|
||||
input.y:3.6-8: refers to: $exp at $1
|
||||
in.y:3.6-8: refers to: $exp at $1
|
||||
exp: exp '+' exp @{ $exp = $1 + $2; @};
|
||||
^^^
|
||||
@end group
|
||||
@group
|
||||
input.y:3.14-16: refers to: $exp at $3
|
||||
in.y:3.14-16: refers to: $exp at $3
|
||||
exp: exp '+' exp @{ $exp = $1 + $2; @};
|
||||
^^^
|
||||
@end group
|
||||
@group
|
||||
input.y:3.32-33: error: $2 of 'exp' has no declared type
|
||||
in.y:3.32-33: error: $2 of 'exp' has no declared type
|
||||
exp: exp '+' exp @{ $exp = $1 + $2; @};
|
||||
^^
|
||||
@end group
|
||||
@@ -10295,19 +10335,30 @@ It is convenient to use a typedef to shorten
|
||||
%@{
|
||||
typedef yy::calcxx_parser::token token;
|
||||
%@}
|
||||
/* Convert ints to the actual type of tokens. */
|
||||
[-+*/] return yy::calcxx_parser::token_type (yytext[0]);
|
||||
":=" return token::ASSIGN;
|
||||
@{int@} @{
|
||||
errno = 0;
|
||||
long n = strtol (yytext, NULL, 10);
|
||||
if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
|
||||
driver.error (*yylloc, "integer is out of range");
|
||||
yylval->ival = n;
|
||||
return token::NUMBER;
|
||||
@}
|
||||
@{id@} yylval->sval = new std::string (yytext); return token::IDENTIFIER;
|
||||
. driver.error (*yylloc, "invalid character");
|
||||
/* Convert ints to the actual type of tokens. */
|
||||
[-+*/] return yy::calcxx_parser::token_type (yytext[0]);
|
||||
|
||||
":=" return token::ASSIGN;
|
||||
|
||||
@group
|
||||
@{int@} @{
|
||||
errno = 0;
|
||||
long n = strtol (yytext, NULL, 10);
|
||||
if (! (INT_MIN <= n && n <= INT_MAX && errno != ERANGE))
|
||||
driver.error (*yylloc, "integer is out of range");
|
||||
yylval->ival = n;
|
||||
return token::NUMBER;
|
||||
@}
|
||||
@end group
|
||||
|
||||
@group
|
||||
@{id@} @{
|
||||
yylval->sval = new std::string (yytext);
|
||||
return token::IDENTIFIER;
|
||||
@}
|
||||
@end group
|
||||
|
||||
. driver.error (*yylloc, "invalid character");
|
||||
%%
|
||||
@end example
|
||||
|
||||
@@ -11358,13 +11409,9 @@ of the rule. @xref{Tracking Locations}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Variable} @@@var{name}
|
||||
In an action, the location of a symbol addressed by name. @xref{Tracking
|
||||
Locations}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Variable} @@[@var{name}]
|
||||
In an action, the location of a symbol addressed by name. @xref{Tracking
|
||||
Locations}.
|
||||
@deffnx {Variable} @@[@var{name}]
|
||||
In an action, the location of a symbol addressed by @var{name}.
|
||||
@xref{Tracking Locations}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Variable} $$
|
||||
@@ -11378,12 +11425,8 @@ right-hand side of the rule. @xref{Actions}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Variable} $@var{name}
|
||||
In an action, the semantic value of a symbol addressed by name.
|
||||
@xref{Actions}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Variable} $[@var{name}]
|
||||
In an action, the semantic value of a symbol addressed by name.
|
||||
@deffnx {Variable} $[@var{name}]
|
||||
In an action, the semantic value of a symbol addressed by @var{name}.
|
||||
@xref{Actions}.
|
||||
@end deffn
|
||||
|
||||
@@ -11401,8 +11444,9 @@ the grammar file. @xref{Grammar Outline, ,Outline of a Bison
|
||||
Grammar}.
|
||||
@end deffn
|
||||
|
||||
@deffn {Construct} /*@dots{}*/
|
||||
Comment delimiters, as in C.
|
||||
@deffn {Construct} /* @dots{} */
|
||||
@deffnx {Construct} // @dots{}
|
||||
Comments, as in C/C++.
|
||||
@end deffn
|
||||
|
||||
@deffn {Delimiter} :
|
||||
@@ -11885,7 +11929,7 @@ Data type of semantic values; @code{int} by default.
|
||||
@item Accepting state
|
||||
A state whose only action is the accept action.
|
||||
The accepting state is thus a consistent state.
|
||||
@xref{Understanding,,}.
|
||||
@xref{Understanding, ,Understanding Your Parser}.
|
||||
|
||||
@item Backus-Naur Form (BNF; also called ``Backus Normal Form'')
|
||||
Formal method of specifying context-free grammars originally proposed
|
||||
|
||||
35
doc/figs/example.dot
Normal file
35
doc/figs/example.dot
Normal file
@@ -0,0 +1,35 @@
|
||||
// Generated by GNU Bison 2.6.90.
|
||||
// Report bugs to <bug-bison@gnu.org>.
|
||||
// Home page: <http://www.gnu.org/software/bison/>.
|
||||
|
||||
digraph "/tmp/fo.y"
|
||||
{
|
||||
node [fontname = courier, shape = box, colorscheme = paired6]
|
||||
edge [fontname = courier]
|
||||
|
||||
0 [label="State 0\n\l 0 $accept: . exp $end\l 1 exp: . a \";\"\l 2 | . b \".\"\l 3 a: . \"0\"\l 4 b: . \"0\"\l"]
|
||||
0 -> 1 [style=solid label="\"0\""]
|
||||
0 -> 2 [style=dashed label="exp"]
|
||||
0 -> 3 [style=dashed label="a"]
|
||||
0 -> 4 [style=dashed label="b"]
|
||||
1 [label="State 1\n\l 3 a: \"0\" . [\";\"]\l 4 b: \"0\" . [\".\"]\l"]
|
||||
1 -> "1R3" [style=solid]
|
||||
"1R3" [label="R3", fillcolor=3, shape=diamond, style=filled]
|
||||
1 -> "1R4" [label="[\".\"]", style=solid]
|
||||
"1R4" [label="R4", fillcolor=3, shape=diamond, style=filled]
|
||||
2 [label="State 2\n\l 0 $accept: exp . $end\l"]
|
||||
2 -> 5 [style=solid label="$end"]
|
||||
3 [label="State 3\n\l 1 exp: a . \";\"\l"]
|
||||
3 -> 6 [style=solid label="\";\""]
|
||||
4 [label="State 4\n\l 2 exp: b . \".\"\l"]
|
||||
4 -> 7 [style=solid label="\".\""]
|
||||
5 [label="State 5\n\l 0 $accept: exp $end .\l"]
|
||||
5 -> "5R0" [style=solid]
|
||||
"5R0" [label="Acc", fillcolor=1, shape=diamond, style=filled]
|
||||
6 [label="State 6\n\l 1 exp: a \";\" .\l"]
|
||||
6 -> "6R1" [style=solid]
|
||||
"6R1" [label="R1", fillcolor=3, shape=diamond, style=filled]
|
||||
7 [label="State 7\n\l 2 exp: b \".\" .\l"]
|
||||
7 -> "7R2" [style=solid]
|
||||
"7R2" [label="R2", fillcolor=3, shape=diamond, style=filled]
|
||||
}
|
||||
4
doc/figs/example.y
Normal file
4
doc/figs/example.y
Normal file
@@ -0,0 +1,4 @@
|
||||
%%
|
||||
exp: a ";" | b ".";
|
||||
a: "0";
|
||||
b: "0";
|
||||
Reference in New Issue
Block a user