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parse.y
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1993-12-09
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/* parse.y - parser for flex input */
%token CHAR NUMBER SECTEND SCDECL XSCDECL WHITESPACE NAME PREVCCL EOF_OP
%{
/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Vern Paxson.
*
* The United States Government has rights in this work pursuant
* to contract no. DE-AC03-76SF00098 between the United States
* Department of Energy and the University of California.
*
* Redistribution and use in source and binary forms are permitted provided
* that: (1) source distributions retain this entire copyright notice and
* comment, and (2) distributions including binaries display the following
* acknowledgement: ``This product includes software developed by the
* University of California, Berkeley and its contributors'' in the
* documentation or other materials provided with the distribution and in
* all advertising materials mentioning features or use of this software.
* Neither the name of the University nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
/* $Header: /home/daffy/u0/vern/flex/RCS/parse.y,v 2.15 93/12/09 13:57:23 vern Exp $ */
/* Some versions of bison are broken in that they use alloca() but don't
* declare it properly. The following is the patented (just kidding!)
* #ifdef chud to fix the problem, courtesy of Francois Pinard.
*/
#ifdef YYBISON
/* AIX requires this to be the first thing in the file. */
#ifdef __GNUC__
#define alloca __builtin_alloca
#else /* not __GNUC__ */
#if HAVE_ALLOCA_H
#include <alloca.h>
#else /* not HAVE_ALLOCA_H */
#ifdef _AIX
#pragma alloca
#else /* not _AIX */
char *alloca ();
#endif /* not _AIX */
#endif /* not HAVE_ALLOCA_H */
#endif /* not __GNUC__ */
#endif /* YYBISON */
/* Bletch, ^^^^ that was ugly! */
#include "flexdef.h"
int pat, scnum, eps, headcnt, trailcnt, anyccl, lastchar, i, actvp, rulelen;
int trlcontxt, xcluflg, cclsorted, varlength, variable_trail_rule;
int *active_ss;
Char clower();
void build_eof_action();
void yyerror();
static int madeany = false; /* whether we've made the '.' character class */
int previous_continued_action; /* whether the previous rule's action was '|' */
/* On some over-ambitious machines, such as DEC Alpha's, the default
* token type is "long" instead of "int"; this leads to problems with
* declaring yylval in flexdef.h. But so far, all the yacc's I've seen
* wrap their definitions of YYSTYPE with "#ifndef YYSTYPE"'s, so the
* following should ensure that the default token type is "int".
*/
#define YYSTYPE int
%}
%%
goal : initlex sect1 sect1end sect2 initforrule
{ /* add default rule */
int def_rule;
pat = cclinit();
cclnegate( pat );
def_rule = mkstate( -pat );
/* Remember the number of the default rule so we
* don't generate "can't match" warnings for it.
*/
default_rule = num_rules;
finish_rule( def_rule, false, 0, 0 );
for ( i = 1; i <= lastsc; ++i )
scset[i] = mkbranch( scset[i], def_rule );
if ( spprdflt )
add_action(
"YY_FATAL_ERROR( \"flex scanner jammed\" )" );
else
add_action( "ECHO" );
add_action( ";\n\tYY_BREAK\n" );
}
;
initlex :
{ /* initialize for processing rules */
/* Create default DFA start condition. */
scinstal( "INITIAL", false );
/* Initially, the start condition scoping is
* "no start conditions active".
*/
actvp = 0;
}
;
sect1 : sect1 startconddecl WHITESPACE namelist1 '\n'
|
| error '\n'
{ synerr( "unknown error processing section 1" ); }
;
sect1end : SECTEND
{
/* We now know how many start conditions there
* are, so create the "activity" map indicating
* which conditions are active.
*/
active_ss = allocate_integer_array( lastsc + 1 );
for ( i = 1; i <= lastsc; ++i )
active_ss[i] = 0;
}
;
startconddecl : SCDECL
{ xcluflg = false; }
| XSCDECL
{ xcluflg = true; }
;
namelist1 : namelist1 WHITESPACE NAME
{ scinstal( nmstr, xcluflg ); }
| NAME
{ scinstal( nmstr, xcluflg ); }
| error
{ synerr( "bad start condition list" ); }
;
sect2 : sect2 initforrule flexrule '\n'
|
;
initforrule :
{
/* Initialize for a parse of one rule. */
trlcontxt = variable_trail_rule = varlength = false;
trailcnt = headcnt = rulelen = 0;
current_state_type = STATE_NORMAL;
previous_continued_action = continued_action;
new_rule();
}
;
flexrule : scon '^' rule
{
pat = $3;
finish_rule( pat, variable_trail_rule,
headcnt, trailcnt );
for ( i = 1; i <= actvp; ++i )
scbol[actvsc[i]] =
mkbranch( scbol[actvsc[i]], pat );
if ( ! bol_needed )
{
bol_needed = true;
if ( performance_report > 1 )
pinpoint_message(
"'^' operator results in sub-optimal performance" );
}
}
| scon rule
{
pat = $2;
finish_rule( pat, variable_trail_rule,
headcnt, trailcnt );
for ( i = 1; i <= actvp; ++i )
scset[actvsc[i]] =
mkbranch( scset[actvsc[i]], pat );
}
| '^' rule
{
pat = $2;
finish_rule( pat, variable_trail_rule,
headcnt, trailcnt );
/* Add to all non-exclusive start conditions,
* including the default (0) start condition.
*/
for ( i = 1; i <= lastsc; ++i )
if ( ! scxclu[i] )
scbol[i] = mkbranch( scbol[i], pat );
if ( ! bol_needed )
{
bol_needed = true;
if ( performance_report > 1 )
pinpoint_message(
"'^' operator results in sub-optimal performance" );
}
}
| rule
{
pat = $1;
finish_rule( pat, variable_trail_rule,
headcnt, trailcnt );
for ( i = 1; i <= lastsc; ++i )
if ( ! scxclu[i] )
scset[i] = mkbranch( scset[i], pat );
}
| scon EOF_OP
{ build_eof_action(); }
| EOF_OP
{
/* This EOF applies to all start conditions
* which don't already have EOF actions.
*/
actvp = 0;
for ( i = 1; i <= lastsc; ++i )
if ( ! sceof[i] )
actvsc[++actvp] = i;
if ( actvp == 0 )
warn(
"all start conditions already have <<EOF>> rules" );
else
build_eof_action();
}
| error
{ synerr( "unrecognized rule" ); }
;
scon : '<' namelist2 '>'
| '<' '*' '>'
{
actvp = 0;
for ( i = 1; i <= lastsc; ++i )
actvsc[++actvp] = i;
}
;
namelist2 : namelist2 ',' sconname
| { actvp = 0; } sconname
| error
{ synerr( "bad start condition list" ); }
;
sconname : NAME
{
if ( (scnum = sclookup( nmstr )) == 0 )
format_pinpoint_message(
"undeclared start condition %s",
nmstr );
else
{
if ( ++actvp >= current_max_scs )
/* Some bozo has included multiple
* instances of start condition names.
*/
pinpoint_message(
"too many start conditions in <> construct!" );
else
actvsc[actvp] = scnum;
}
}
;
rule : re2 re
{
if ( transchar[lastst[$2]] != SYM_EPSILON )
/* Provide final transition \now/ so it
* will be marked as a trailing context
* state.
*/
$2 = link_machines( $2,
mkstate( SYM_EPSILON ) );
mark_beginning_as_normal( $2 );
current_state_type = STATE_NORMAL;
if ( previous_continued_action )
{
/* We need to treat this as variable trailing
* context so that the backup does not happen
* in the action but before the action switch
* statement. If the backup happens in the
* action, then the rules "falling into" this
* one's action will *also* do the backup,
* erroneously.
*/
if ( ! varlength || headcnt != 0 )
warn(
"trailing context made variable due to preceding '|' action" );
/* Mark as variable. */
varlength = true;
headcnt = 0;
}
if ( lex_compat || (varlength && headcnt == 0) )
{ /* variable trailing context rule */
/* Mark the first part of the rule as the
* accept