No empty .Rs/.Re

[netbsd-mini2440.git] / usr.bin / lex / parse.y

/* parse.y - parser for flex input */

%token CHAR NUMBER SECTEND SCDECL XSCDECL NAME PREVCCL EOF_OP
%token OPTION_OP OPT_OUTFILE OPT_PREFIX OPT_YYCLASS

%token CCE_ALNUM CCE_ALPHA CCE_BLANK CCE_CNTRL CCE_DIGIT CCE_GRAPH
%token CCE_LOWER CCE_PRINT CCE_PUNCT CCE_SPACE CCE_UPPER CCE_XDIGIT

%{
/*-
 * 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.
 */

  /* $NetBSD: parse.y,v 1.10 2002/01/29 10:20:34 tv 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.  What a piece.  */
# ifdef _AIX
 #pragma alloca
# endif
#endif

#include "flexdef.h"

/* The remainder of the alloca() cruft has to come after including flexdef.h,
 * so HAVE_ALLOCA_H is (possibly) defined.
 */
#ifdef YYBISON
# ifdef __GNUC__
#  ifndef alloca
#   define alloca __builtin_alloca
#  endif
# else
#  if HAVE_ALLOCA_H
#   include <alloca.h>
#  else
#   ifdef __hpux
void *alloca ();
#   else
#    ifdef __TURBOC__
#     include <malloc.h>
#    else
char *alloca ();
#    endif
#   endif
#  endif
# endif
#endif

/* Bletch, ^^^^ that was ugly! */


int pat, scnum, eps, headcnt, trailcnt, anyccl, lastchar, i, rulelen;
int trlcontxt, xcluflg, currccl, cclsorted, varlength, variable_trail_rule;

int *scon_stk;
int scon_stk_ptr;

static int madeany = false;  /* whether we've made the '.' character class */
int previous_continued_action;  /* whether the previous rule's action was '|' */

/* Expand a POSIX character class expression. */
#define CCL_EXPR(func) \
        { \
        int c; \
        for ( c = 0; c < csize; ++c ) \
                if ( isascii(c) && func(c) ) \
                        ccladd( currccl, c ); \
        }

/* While POSIX defines isblank(), it's not ANSI C. */
#define IS_BLANK(c) ((c) == ' ' || (c) == '\t')

/* 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 );
                        }
                ;

sect1           :  sect1 startconddecl namelist1
                |  sect1 options
                |
                |  error
                        { synerr( "unknown error processing section 1" ); }
                ;

sect1end        :  SECTEND
                        {
                        check_options();
                        scon_stk = allocate_integer_array( lastsc + 1 );
                        scon_stk_ptr = 0;
                        }
                ;

startconddecl   :  SCDECL
                        { xcluflg = false; }

                |  XSCDECL
                        { xcluflg = true; }
                ;

namelist1       :  namelist1 NAME
                        { scinstal( nmstr, xcluflg ); }

                |  NAME
                        { scinstal( nmstr, xcluflg ); }

                |  error
                        { synerr( "bad start condition list" ); }
                ;

options         :  OPTION_OP optionlist
                ;

optionlist      :  optionlist option
                |
                ;

option          :  OPT_OUTFILE '=' NAME
                        {
                        outfilename = copy_string( nmstr );
                        did_outfilename = 1;
                        }
                |  OPT_PREFIX '=' NAME
                        { prefix = copy_string( nmstr ); }
                |  OPT_YYCLASS '=' NAME
                        { yyclass = copy_string( nmstr ); }
                ;

sect2           :  sect2 scon initforrule flexrule '\n'
                        { scon_stk_ptr = $2; }
                |  sect2 scon '{' sect2 '}'
                        { scon_stk_ptr = $2; }
                |
                ;

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;
                        in_rule = true;

                        new_rule();
                        }
                ;

flexrule        :  '^' rule
                        {
                        pat = $2;
                        finish_rule( pat, variable_trail_rule,
                                headcnt, trailcnt );

                        if ( scon_stk_ptr > 0 )
                                {
                                for ( i = 1; i <= scon_stk_ptr; ++i )
                                        scbol[scon_stk[i]] =
                                                mkbranch( scbol[scon_stk[i]],
                                                                pat );
                                }

                        else
                                {
                                /* 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 );

                        if ( scon_stk_ptr > 0 )
                                {
                                for ( i = 1; i <= scon_stk_ptr; ++i )
                                        scset[scon_stk[i]] =
                                                mkbranch( scset[scon_stk[i]],
                                                                pat );
                                }

                        else
                                {
                                for ( i = 1; i <= lastsc; ++i )
                                        if ( ! scxclu[i] )
                                                scset[i] =
                                                        mkbranch( scset[i],
                                                                pat );
                                }
                        }

                |  EOF_OP
                        {
                        if ( scon_stk_ptr > 0 )
                                build_eof_action();
        
                        else
                                {
                                /* This EOF applies to all start conditions
                                 * which don't already have EOF actions.
                                 */
                                for ( i = 1; i <= lastsc; ++i )
                                        if ( ! sceof[i] )
                                                scon_stk[++scon_stk_ptr] = i;

                                if ( scon_stk_ptr == 0 )
                                        lwarn(
                        "all start conditions already have <<EOF>> rules" );

                                else
                                        build_eof_action();
                                }
                        }

                |  error
                        { synerr( "unrecognized rule" ); }
                ;

scon_stk_ptr    :
                        { $$ = scon_stk_ptr; }
                ;

scon            :  '<' scon_stk_ptr namelist2 '>'
                        { $$ = $2; }

                |  '<' '*' '>'
                        {
                        $$ = scon_stk_ptr;

                        for ( i = 1; i <= lastsc; ++i )
                                {
                                int j;

                                for ( j = 1; j <= scon_stk_ptr; ++j )
                                        if ( scon_stk[j] == i )
                                                break;

                                if ( j > scon_stk_ptr )
                                        scon_stk[++scon_stk_ptr] = i;
                                }
                        }

                |
                        { $$ = scon_stk_ptr; }
                ;

namelist2       :  namelist2 ',' sconname

                |  sconname

                |  error
                        { synerr( "bad start condition list" ); }
                ;

sconname        :  NAME
                        {
                        if ( (scnum = sclookup( nmstr )) == 0 )
                                format_pinpoint_message(
                                        "undeclared start condition %s",
                                        nmstr );
                        else
                                {
                                for ( i = 1; i <= scon_stk_ptr; ++i )
                                        if ( scon_stk[i] == scnum )
                                                {
                                                format_warn(
                                                        "<%s> specified twice",
                                                        scname[scnum] );
                                                break;
                                                }

                                if ( i > scon_stk_ptr )
                                        scon_stk[++scon_stk_ptr] = 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 )
                                        lwarn(
                "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
                                 * accepting "head" part of a trailing
                                 * context rule.
                                 *
                                 * By the way, we didn't do this at the
                                 * beginning of this production because back
                                 * then current_state_type was set up for a
                                 * trail rule, and add_accept() can create
                                 * a new state ...
                                 */
                                add_accept( $1,
                                        num_rules | YY_TRAILING_HEAD_MASK );
                                variable_trail_rule = true;
                                }
                        
                        else
                                trailcnt = rulelen;

                        $$ = link_machines( $1, $2 );
                        }

                |  re2 re '$'
                        { synerr( "trailing context used twice" ); }

                |  re '$'
                        {
                        headcnt = 0;
                        trailcnt = 1;
                        rulelen = 1;
                        varlength = false;

                        current_state_type = STATE_TRAILING_CONTEXT;

                        if ( trlcontxt )
                                {
                                synerr( "trailing context used twice" );
                                $$ = mkstate( SYM_EPSILON );
                                }

                        else if ( previous_continued_action )
                                {
                                /* See the comment in the rule for "re2 re"
                                 * above.
                                 */
                                lwarn(
                "trailing context made variable due to preceding '|' action" );

                                varlength = true;
                                }

                        if ( lex_compat || varlength )
                                {
                                /* Again, see the comment in the rule for
                                 * "re2 re" above.
                                 */
                                add_accept( $1,
                                        num_rules | YY_TRAILING_HEAD_MASK );
                                variable_trail_rule = true;
                                }

                        trlcontxt = true;

                        eps = mkstate( SYM_EPSILON );
                        $$ = link_machines( $1,
                                link_machines( eps, mkstate( '\n' ) ) );
                        }

                |  re
                        {
                        $$ = $1;

                        if ( trlcontxt )
                                {
                                if ( lex_compat || (varlength && headcnt == 0) )
                                        /* Both head and trail are
                                         * variable-length.
                                         */
                                        variable_trail_rule = true;
                                else
                                        trailcnt = rulelen;
                                }
                        }
                ;


re              :  re '|' series
                        {
                        varlength = true;
                        $$ = mkor( $1, $3 );
                        }

                |  series
                        { $$ = $1; }
                ;


re2             :  re '/'
                        {
                        /* This rule is written separately so the
                         * reduction will occur before the trailing
                         * series is parsed.
                         */

                        if ( trlcontxt )
                                synerr( "trailing context used twice" );
                        else
                                trlcontxt = true;

                        if ( varlength )
                                /* We hope the trailing context is
                                 * fixed-length.
                                 */
                                varlength = false;
                        else
                                headcnt = rulelen;

                        rulelen = 0;

                        current_state_type = STATE_TRAILING_CONTEXT;
                        $$ = $1;
                        }
                ;

series          :  series singleton
                        {
                        /* This is where concatenation of adjacent patterns
                         * gets done.
                         */
                        $$ = link_machines( $1, $2 );
                        }

                |  singleton
                        { $$ = $1; }
                ;

singleton       :  singleton '*'
                        {
                        varlength = true;

                        $$ = mkclos( $1 );
                        }

                |  singleton '+'
                        {
                        varlength = true;
                        $$ = mkposcl( $1 );
                        }

                |  singleton '?'
                        {
                        varlength = true;
                        $$ = mkopt( $1 );
                        }

                |  singleton '{' NUMBER ',' NUMBER '}'
                        {
                        varlength = true;

                        if ( $3 > $5 || $3 < 0 )
                                {
                                synerr( "bad iteration values" );
                                $$ = $1;
                                }
                        else
                                {
                                if ( $3 == 0 )
                                        {
                                        if ( $5 <= 0 )
                                                {
                                                synerr(
                                                "bad iteration values" );
                                                $$ = $1;
                                                }
                                        else
                                                $$ = mkopt(
                                                        mkrep( $1, 1, $5 ) );
                                        }
                                else
                                        $$ = mkrep( $1, $3, $5 );
                                }
                        }

                |  singleton '{' NUMBER ',' '}'
                        {
                        varlength = true;

                        if ( $3 <= 0 )
                                {
                                synerr( "iteration value must be positive" );
                                $$ = $1;
                                }

                        else
                                $$ = mkrep( $1, $3, INFINITY );
                        }

                |  singleton '{' NUMBER '}'
                        {
                        /* The singleton could be something like "(foo)",
                         * in which case we have no idea what its length
                         * is, so we punt here.
                         */
                        varlength = true;

                        if ( $3 <= 0 )
                                {
                                synerr( "iteration value must be positive" );
                                $$ = $1;
                                }

                        else
                                $$ = link_machines( $1,
                                                copysingl( $1, $3 - 1 ) );
                        }

                |  '.'
                        {
                        if ( ! madeany )
                                {
                                /* Create the '.' character class. */
                                anyccl = cclinit();
                                ccladd( anyccl, '\n' );
                                cclnegate( anyccl );

                                if ( useecs )
                                        mkeccl( ccltbl + cclmap[anyccl],
                                                ccllen[anyccl], nextecm,
                                                ecgroup, csize, csize );

                                madeany = true;
                                }

                        ++rulelen;

                        $$ = mkstate( -anyccl );
                        }

                |  fullccl
                        {
                        if ( ! cclsorted )
                                /* Sort characters for fast searching.  We
                                 * use a shell sort since this list could
                                 * be large.
                                 */
                                cshell( ccltbl + cclmap[$1], ccllen[$1], true );

                        if ( useecs )
                                mkeccl( ccltbl + cclmap[$1], ccllen[$1],
                                        nextecm, ecgroup, csize, csize );

                        ++rulelen;

                        $$ = mkstate( -$1 );
                        }

                |  PREVCCL
                        {
                        ++rulelen;

                        $$ = mkstate( -$1 );
                        }

                |  '"' string '"'
                        { $$ = $2; }

                |  '(' re ')'
                        { $$ = $2; }

                |  CHAR
                        {
                        ++rulelen;

                        if ( caseins && $1 >= 'A' && $1 <= 'Z' )
                                $1 = clower( $1 );

                        $$ = mkstate( $1 );
                        }
                ;

fullccl         :  '[' ccl ']'
                        { $$ = $2; }

                |  '[' '^' ccl ']'
                        {
                        cclnegate( $3 );
                        $$ = $3;
                        }
                ;

ccl             :  ccl CHAR '-' CHAR
                        {
                        if ( caseins )
                                {
                                if ( $2 >= 'A' && $2 <= 'Z' )
                                        $2 = clower( $2 );
                                if ( $4 >= 'A' && $4 <= 'Z' )
                                        $4 = clower( $4 );
                                }

                        if ( $2 > $4 )
                                synerr( "negative range in character class" );

                        else
                                {
                                for ( i = $2; i <= $4; ++i )
                                        ccladd( $1, i );

                                /* Keep track if this ccl is staying in
                                 * alphabetical order.
                                 */
                                cclsorted = cclsorted && ($2 > lastchar);
                                lastchar = $4;
                                }

                        $$ = $1;
                        }

                |  ccl CHAR
                        {
                        if ( caseins && $2 >= 'A' && $2 <= 'Z' )
                                $2 = clower( $2 );

                        ccladd( $1, $2 );
                        cclsorted = cclsorted && ($2 > lastchar);
                        lastchar = $2;
                        $$ = $1;
                        }

                |  ccl ccl_expr
                        {
                        /* Too hard to properly maintain cclsorted. */
                        cclsorted = false;
                        $$ = $1;
                        }

                |
                        {
                        cclsorted = true;
                        lastchar = 0;
                        currccl = $$ = cclinit();
                        }
                ;

ccl_expr:          CCE_ALNUM    { CCL_EXPR(isalnum) }
                |  CCE_ALPHA    { CCL_EXPR(isalpha) }
                |  CCE_BLANK    { CCL_EXPR(IS_BLANK) }
                |  CCE_CNTRL    { CCL_EXPR(iscntrl) }
                |  CCE_DIGIT    { CCL_EXPR(isdigit) }
                |  CCE_GRAPH    { CCL_EXPR(isgraph) }
                |  CCE_LOWER    { CCL_EXPR(islower) }
                |  CCE_PRINT    { CCL_EXPR(isprint) }
                |  CCE_PUNCT    { CCL_EXPR(ispunct) }
                |  CCE_SPACE    { CCL_EXPR(isspace) }
                |  CCE_UPPER    {
                                if ( caseins )
                                        CCL_EXPR(islower)
                                else
                                        CCL_EXPR(isupper)
                                }
                |  CCE_XDIGIT   { CCL_EXPR(isxdigit) }
                ;
                
string          :  string CHAR
                        {
                        if ( caseins && $2 >= 'A' && $2 <= 'Z' )
                                $2 = clower( $2 );

                        ++rulelen;

                        $$ = link_machines( $1, mkstate( $2 ) );
                        }

                |
                        { $$ = mkstate( SYM_EPSILON ); }
                ;

%%


/* build_eof_action - build the "<<EOF>>" action for the active start
 *                    conditions
 */

void build_eof_action()
        {
        register int i;
        char action_text[MAXLINE];

        for ( i = 1; i <= scon_stk_ptr; ++i )
                {
                if ( sceof[scon_stk[i]] )
                        format_pinpoint_message(
                                "multiple <<EOF>> rules for start condition %s",
                                scname[scon_stk[i]] );

                else
                        {
                        sceof[scon_stk[i]] = true;
                        snprintf(action_text, sizeof(action_text),
                            "case YY_STATE_EOF(%s):\n", scname[scon_stk[i]]);
                        add_action( action_text );
                        }
                }

        line_directive_out( (FILE *) 0, 1 );

        /* This isn't a normal rule after all - don't count it as
         * such, so we don't have any holes in the rule numbering
         * (which make generating "rule can never match" warnings
         * more difficult.
         */
        --num_rules;
        ++num_eof_rules;
        }


/* format_synerr - write out formatted syntax error */

void format_synerr( msg, arg )
char msg[], arg[];
        {
        char errmsg[MAXLINE];

        (void) snprintf(errmsg, sizeof(errmsg), msg, arg);
        synerr( errmsg );
        }


/* synerr - report a syntax error */

void synerr( str )
char str[];
        {
        syntaxerror = true;
        pinpoint_message( str );
        }


/* format_warn - write out formatted warning */

void format_warn( msg, arg )
char msg[], arg[];
        {
        char warn_msg[MAXLINE];

        (void) snprintf(warn_msg, sizeof(warn_msg), msg, arg);
        lwarn( warn_msg );
        }


/* lwarn - report a warning, unless -w was given */

void lwarn( str )
char str[];
        {
        line_warning( str, linenum );
        }

/* format_pinpoint_message - write out a message formatted with one string,
 *                           pinpointing its location
 */

void format_pinpoint_message( msg, arg )
char msg[], arg[];
        {
        char errmsg[MAXLINE];

        (void) snprintf(errmsg, sizeof(errmsg), msg, arg);
        pinpoint_message( errmsg );
        }


/* pinpoint_message - write out a message, pinpointing its location */

void pinpoint_message( str )
char str[];
        {
        line_pinpoint( str, linenum );
        }


/* line_warning - report a warning at a given line, unless -w was given */

void line_warning( str, line )
char str[];
int line;
        {
        char warning[MAXLINE];

        if ( ! nowarn )
                {
                snprintf(warning, sizeof(warning), "warning, %s", str);
                line_pinpoint( warning, line );
                }
        }


/* line_pinpoint - write out a message, pinpointing it at the given line */

void line_pinpoint( str, line )
char str[];
int line;
        {
        fprintf( stderr, "\"%s\", line %d: %s\n", infilename, line, str );
        }


/* yyerror - eat up an error message from the parser;
 *           currently, messages are ignore
 */

void yyerror( msg )
char msg[];
        {
        }