y1.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char sccsid[] = "@(#)y1.c	1.1	11/7/83";
#endif not lint

# include "dextern"
# include "yaccpar.h"

/************************************************************************
 *									*
 *			Copyright (c) 1983 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *
 *			Modification History
 *
 *	Stephen Reilly, 07-Nov-83
 * 001- We no longer read yaccpar, which is the template parser, it is now
 *	in an include file called yaccpar.h.  The reason for this is
 *	so yacc can be part of the binary kit.
 *
 ***********************************************************************/

	/* variables used locally */

	/* lookahead computations */

int tbitset;  /* size of lookahead sets */
struct looksets lkst [ LSETSIZE ];
int nlset = 0; /* next lookahead set index */
int nolook = 0; /* flag to suppress lookahead computations */
struct looksets clset;  /* temporary storage for lookahead computations */

	/* working set computations */

struct wset wsets[ WSETSIZE ];
struct wset *cwp;

	/* state information */

int nstate = 0;		/* number of states */
struct item *pstate[NSTATES+2];	/* pointers to the descriptions of the states */
int tystate[NSTATES];	/* contains type information about the states */
int indgo[NSTATES];		/* index to the stored goto table */
int tstates[ NTERMS ]; /* states generated by terminal gotos */
int ntstates[ NNONTERM ]; /* states generated by nonterminal gotos */
int mstates[ NSTATES ]; /* chain of overflows of term/nonterm generation lists  */

	/* storage for the actions in the parser */

int amem[ACTSIZE];	/* action table storage */
int *memp = amem;	/* next free action table position */

	/* other storage areas */

int temp1[TEMPSIZE]; /* temporary storage, indexed by terms + ntokens or states */
int lineno= 1; /* current input line number */
int fatfl = 1;  	/* if on, error is fatal */
int nerrors = 0;	/* number of errors */

	/* storage for information about the nonterminals */

int **pres[NNONTERM+2];  /* vector of pointers to productions yielding each nonterminal */
struct looksets *pfirst[NNONTERM+2];  /* vector of pointers to first sets for each nonterminal */
int pempty[NNONTERM+1];  /* vector of nonterminals nontrivially deriving e */

main(argc,argv) int argc; char *argv[]; {

	setup(argc,argv); /* initialize and read productions */
	tbitset = NWORDS(ntokens);
	cpres(); /* make table of which productions yield a given nonterminal */
	cempty(); /* make a table of which nonterminals can match the empty string */
	cpfir(); /* make a table of firsts of nonterminals */
	stagen(); /* generate the states */
	output();  /* write the states and the tables */
	go2out();
	hideprod();
	summary();
	callopt();
	others();
	exit(0);
	}

others(){ /* put out other arrays, copy the parsers */
	register c, i, j;
	char **t, *p;

/*		SLR001
 *
 *	We no longer read the file yaccpar it is not part of an include
 *	file
 *
 *	 finput = fopen( PARSER, "r" );
 *	if( finput == NULL ) error( "cannot find parser %s", PARSER );
 */
	warray( "yyr1", levprd, nprod );

	aryfil( temp1, nprod, 0 );
	PLOOP(1,i)temp1[i] = prdptr[i+1]-prdptr[i]-2;
	warray( "yyr2", temp1, nprod );

	aryfil( temp1, nstate, -1000 );
	TLOOP(i){
		for( j=tstates[i]; j!=0; j=mstates[j] ){
			temp1[j] = tokset[i].value;
			}
		}
	NTLOOP(i){
		for( j=ntstates[i]; j!=0; j=mstates[j] ){
			temp1[j] = -i;
			}
		}
	warray( "yychk", temp1, nstate );

	warray( "yydef", defact, nstate );

	/* copy parser text */

/*				SLR001
 *	This protion of the code has been rewritten so it now read the
 *	data structer called  yacclin which contains the template parser
 */
	for (  t = yacclin ; *t; t++ )
	    {
	    p = *t;
	    while ( (c= *p++ ) != '\0' ) {
		if( c == '$' ){
			if( (c= *p++ ) != 'A' ) putc( '$', ftable );
			else { /* copy actions */
				faction = fopen( ACTNAME, "r" );
				if( faction == NULL ) error( "cannot reopen action tempfile" );
				while( (c=getc(faction) ) != EOF ) putc( c, ftable );
				fclose(faction);
				ZAPFILE(ACTNAME);
				c = *p++;
				}
			}
		putc( c, ftable );
		}
	    }

	fclose( ftable );
	}

char *chcopy( p, q )  char *p, *q; {
	/* copies string q into p, returning next free char ptr */
	while( *p = *q++ ) ++p;
	return( p );
	}

# define ISIZE 400
char *writem(pp) int *pp; { /* creates output string for item pointed to by pp */
	int i,*p;
	static char sarr[ISIZE];
	char *q;

	for( p=pp; *p>0 ; ++p ) ;
	p = prdptr[-*p];
	q = chcopy( sarr, nontrst[*p-NTBASE].name );
	q = chcopy( q, " : " );

	for(;;){
		*q++ = ++p==pp ? '_' : ' ';
		*q = '\0';
		if((i = *p) <= 0) break;
		q = chcopy( q, symnam(i) );
		if( q> &sarr[ISIZE-30] ) error( "item too big" );
		}

	if( (i = *pp) < 0 ){ /* an item calling for a reduction */
		q = chcopy( q, "    (" );
		sprintf( q, "%d)", -i );
		}

	return( sarr );
	}

char *symnam(i){ /* return a pointer to the name of symbol i */
	char *cp;

	cp = (i>=NTBASE) ? nontrst[i-NTBASE].name : tokset[i].name ;
	if( *cp == ' ' ) ++cp;
	return( cp );
	}

struct wset *zzcwp = wsets;
int zzgoent = 0;
int zzgobest = 0;
int zzacent = 0;
int zzexcp = 0;
int zzclose = 0;
int zzsrconf = 0;
int * zzmemsz = mem0;
int zzrrconf = 0;

summary(){ /* output the summary on the tty */

	if( foutput!=NULL ){
		fprintf( foutput, "\n%d/%d terminals, %d/%d nonterminals\n", ntokens, NTERMS,
			    nnonter, NNONTERM );
		fprintf( foutput, "%d/%d grammar rules, %d/%d states\n", nprod, NPROD, nstate, NSTATES );
		fprintf( foutput, "%d shift/reduce, %d reduce/reduce conflicts reported\n", zzsrconf, zzrrconf );
		fprintf( foutput, "%d/%d working sets used\n", zzcwp-wsets,  WSETSIZE );
		fprintf( foutput, "memory: states,etc. %d/%d, parser %d/%d\n", zzmemsz-mem0, MEMSIZE,
			    memp-amem, ACTSIZE );
		fprintf( foutput, "%d/%d distinct lookahead sets\n", nlset, LSETSIZE );
		fprintf( foutput, "%d extra closures\n", zzclose - 2*nstate );
		fprintf( foutput, "%d shift entries, %d exceptions\n", zzacent, zzexcp );
		fprintf( foutput, "%d goto entries\n", zzgoent );
		fprintf( foutput, "%d entries saved by goto default\n", zzgobest );
		}
	if( zzsrconf!=0 || zzrrconf!=0 ){
		  fprintf( stdout,"\nconflicts: ");
		  if( zzsrconf )fprintf( stdout, "%d shift/reduce" , zzsrconf );
		  if( zzsrconf && zzrrconf )fprintf( stdout, ", " );
		  if( zzrrconf )fprintf( stdout, "%d reduce/reduce" , zzrrconf );
		  fprintf( stdout, "\n" );
		  }

	fclose( ftemp );
	if( fdefine != NULL ) fclose( fdefine );
	}

/* VARARGS1 */
error(s,a1) char *s; { /* write out error comment */
	
	++nerrors;
	fprintf( stderr, "\n fatal error: ");
	fprintf( stderr, s,a1);
	fprintf( stderr, ", line %d\n", lineno );
	if( !fatfl ) return;
	summary();
	exit(1);
	}

aryfil( v, n, c ) int *v,n,c; { /* set elements 0 through n-1 to c */
	int i;
	for( i=0; i<n; ++i ) v[i] = c;
	}

setunion( a, b ) register *a, *b; {
	/* set a to the union of a and b */
	/* return 1 if b is not a subset of a, 0 otherwise */
	register i, x, sub;

	sub = 0;
	SETLOOP(i){
		*a = (x = *a)|*b++;
		if( *a++ != x ) sub = 1;
		}
	return( sub );
	}

prlook( p ) struct looksets *p;{
	register j, *pp;
	pp = p->lset;
	if( pp == 0 ) fprintf( foutput, "\tNULL");
	else {
		fprintf( foutput, " { " );
		TLOOP(j) {
			if( BIT(pp,j) ) fprintf( foutput,  "%s ", symnam(j) );
			}
		fprintf( foutput,  "}" );
		}
	}

cpres(){ /* compute an array with the beginnings of  productions yielding given nonterminals
	The array pres points to these lists */
	/* the array pyield has the lists: the total size is only NPROD+1 */
	register **pmem;
	register c, j, i;
	static int * pyield[NPROD];

	pmem = pyield;

	NTLOOP(i){
		c = i+NTBASE;
		pres[i] = pmem;
		fatfl = 0;  /* make undefined  symbols  nonfatal */
		PLOOP(0,j){
			if (*prdptr[j] == c) *pmem++ =  prdptr[j]+1;
			}
		if(pres[i] == pmem){
			error("nonterminal %s not defined!", nontrst[i].name);
			}
		}
	pres[i] = pmem;
	fatfl = 1;
	if( nerrors ){
		summary();
		exit(1);
		}
	if( pmem != &pyield[nprod] ) error( "internal Yacc error: pyield %d", pmem-&pyield[nprod] );
	}

int indebug = 0;
cpfir() {
	/* compute an array with the first of nonterminals */
	register *p, **s, i, **t, ch, changes;

	zzcwp = &wsets[nnonter];
	NTLOOP(i){
		aryfil( wsets[i].ws.lset, tbitset, 0 );
		t = pres[i+1];
		for( s=pres[i]; s<t; ++s ){ /* initially fill the sets */
			for( p = *s; (ch = *p) > 0 ; ++p ) {
				if( ch < NTBASE ) {
					SETBIT( wsets[i].ws.lset, ch );
					break;
					}
				else if( !pempty[ch-NTBASE] ) break;
				}
			}
		}

	/* now, reflect transitivity */

	changes = 1;
	while( changes ){
		changes = 0;
		NTLOOP(i){
			t = pres[i+1];
			for( s=pres[i]; s<t; ++s ){
				for( p = *s; ( ch = (*p-NTBASE) ) >= 0; ++p ) {
					changes |= setunion( wsets[i].ws.lset, wsets[ch].ws.lset );
					if( !pempty[ch] ) break;
					}
				}
			}
		}

	NTLOOP(i) pfirst[i] = flset( &wsets[i].ws );
	if( !indebug ) return;