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1.1 root 1: /*
2: * Copyright (c) 1979 Regents of the University of California.
3: * All rights reserved. The Berkeley software License Agreement
4: * specifies the terms and conditions for redistribution.
5: */
6:
7: #ifndef lint
8: static char sccsid[] = "@(#)ey1.c 5.2 (Berkeley) 9/22/88";
9: #endif not lint
10:
11: # include "ey.h"
12: /* * * * * e y a c c * * * * */
13:
14: /**** NB -----
15: *
16: * This version of yacc, known as "eyacc" has been slightly but
17: * importantly modified to allow error recovery in the UNIX Pascal
18: * translator "pi" and also in "pix".
19: *
20: * Changes here include:
21: *
22: * 1) Enumeration of test actions when "error" is an input token.
23: *
24: * 2) Change to the encoding of the action entries. Test entries
25: * are encoded as the arithmetic inverse of the symbol being tested
26: * for. This is an optimization that makes the parser run at the
27: * same speed even though, with error productions and enumerated
28: * lookaheads, it would normally be much slower. Of course the
29: * same thing could be done to the regular yacc...
30: *
31: * 3) Different table sizes
32: *
33: * 4) Recognizes form feeds
34: *
35: * 5) Also most of the numbers for the sizes of the tables have been
36: * increased, to an extent to allow for "eyacc"ing of the Pascal grammar
37: * and of a grammar which I have for "EUCLID".
38: *
39: * There seem to be subtle dependencies between the various magic
40: * numbers... I found some of them but to be safe most of the limits
41: * are very generous... for this reason "eyacc" will most likely
42: * have to run separate i/d... no matter.
43: *
44: * Bill Joy
45: * Computer Science Division
46: * EECS Department
47: * University of California, Berkeley
48: * Berkeley, California 94704
49: *
50: * Office: (415) 642-4948
51: * Home: (415) 524-4510
52: ****/
53:
54: /* features to be fixed up ...
55:
56: *** Print estimate of total space needed for parser
57: *** Either list inputs on y.output, or list empty prdn's in states
58: *** Mention nonterms not used (or, rules. not reduced) as nonfatal error
59: *** Output states where conflicts were found by default on y.output
60: *** Engage in newspeak: production=>grammar rules, term=>token, etc.
61: *** handle # define, #ifdef, etc., in yacc actions, %{ %}
62: */
63:
64: /* new features to be added
65:
66: *** reductions by single productions ( by request )
67: *** follow sets for start symbol
68: *** option to only do slr(1)
69: *** easily changed array names on output
70: *** allocate core, rather than predefined
71: *** input controlled by a grammar
72: *** support multiple choices for conflicts
73: *** better conflict diagnostics
74: */
75:
76: extern char *symnam();
77:
78: main(argc,argv) int argc; char *argv[]; {
79: auto int n;
80:
81: setup(argc,argv); /* initialize and read productions */
82: tbitset = (nterms+16)/16;
83: cpres(); /* make table of which productions yield a given nonterminal */
84: cempty(); /* make a table of which nonterminals can match the empty string */
85: cpfir(); /* make a table of e free first lists */
86: stagen(); /* generate the states */
87: output(); /* write the states and the tables */
88: go2out();
89: summary();
90: exit(0);
91: }
92:
93: settty()
94: /* sets the output file to y.output */
95: {
96: cflush( foutput ); /* a bit of a cheat */
97: cout = foutput;
98: }
99:
100: settab(){ /* sets the output file to y.tab.c */
101:
102: cflush( ftable );
103: cout = ftable;
104: }
105:
106: char *chcopy( p, q ) char *p, *q; {
107: /* copies string q into p, returning next free char ptr */
108: while( *p = *q++ ) ++p;
109: return( p );
110: }
111:
112: char *writem(pp) struct item *pp; { /* creates output string for item pointed to by pp */
113: int i,*p;
114: static char sarr[100];
115: char *q;
116:
117: for( p=pp->pitem; *p>0 ; ++p ) ;
118: p = prdptr[-*p];
119: q = chcopy( sarr, nontrst[*p-NTBASE].name );
120: q = chcopy( q, " : " );
121:
122: for(;;){
123: *q++ = ++p==(pp->pitem) ? '_' : ' ';
124: if((i = *p) <= 0) break;
125: q = chcopy( q, symnam(i) );
126: }
127:
128: *q = '\0' ;
129: return( sarr );
130: }
131:
132: char *symnam(i){ /* return a pointer to the name of symbol i */
133: char *cp;
134:
135: cp = (i>=NTBASE) ? nontrst[i-NTBASE].name : trmset[i].name ;
136: if( *cp == ' ' ) ++cp;
137: return( cp );
138: }
139:
140: summary(){ /* output the summary on the tty */
141:
142: int i, s, *pn;
143:
144:
145: if( !rflag ){
146: settab();
147: fprintf( cout , "\nint nterms %d;",nterms);
148: fprintf( cout , "\nint nnonter %d;", nnonter);
149: fprintf( cout , "\nint nstate %d;", nstate);
150: fprintf( cout , "\nchar *yysterm[] {");
151: for (i=1;i<=nterms;i++) if( trmset[i].value >= 0400 ) fprintf( cout , "\n\"%s\",",symnam(i));
152: fprintf( cout , "\n0 };\n" );
153: fprintf( cout , "\nchar *yysnter[] {");
154: for (i=0;i<nnonter;i++) fprintf( cout , "\n\"%s\",",nontrst[i].name);
155: fprintf( cout , "\n\"%s\" };\n",nontrst[nnonter].name);
156: }
157:
158: settty();
159: fprintf( cout , "\n%d/%d terminals, %d/%d nonterminals\n", nterms, tlim,
160: nnonter, ntlim );
161: fprintf( cout , "%d/%d grammar rules, %d/%d states\n", nprod, prdlim, nstate, stsize );
162: fprintf( cout , "%d shift/reduce, %d reduce/reduce conflicts reported\n", zzsrconf, zzrrconf );
163: pn = (int *)pstate[nstate+1];
164: fprintf( cout , "%d/%d working sets used\n", zzcwset, wssize );
165: fprintf( cout , "memory: states,etc. %d/%d, parser %d/%d\n", pn-mem0, memsiz,
166: memact, actsiz );
167: fprintf( cout , "%d/%d distinct lookahead sets\n", nlset, lsetsz );
168: fprintf( cout , "%d extra closures\n", zzclose - 2*nstate );
169: fprintf( cout , "%d action entries\n", zzacent );
170: fprintf( cout , "%d action entries saved through merging %d states\n",zzacsave,zznsave);
171: fprintf( cout , "%d goto entries\n", zzgoent );
172: fprintf( cout , "%d entries saved by goto default\n", zzgobest );
173: fprintf( cout , "%d lookahead sets saved\n", savedlook);
174: if( zzsrconf!=0 || zzrrconf!=0 ){
175: cflush( errfileno );
176: cout = errfileno;
177: fprintf( cout , "\nconflicts: ");
178: if( zzsrconf )fprintf( cout , "%d shift/reduce" , zzsrconf );
179: if( zzsrconf && zzrrconf )fprintf( cout , ", " );
180: if( zzrrconf )fprintf( cout , "%d reduce/reduce" , zzrrconf );
181: fprintf( cout , "\n" );
182: }
183: }
184:
185: error(s,a1){ /* write out error comment */
186:
187: int c;
188: ++nerrors;
189: cflush( errfileno );
190: cout = errfileno; /* set output to tty */
191: fprintf( cout , "\n fatal error: ");
192: fprintf( cout , s,a1);
193: fprintf( cout , ", line %d\n", lineno );
194: if( !fatfl ) return;
195: summary();
196: cexit(1);
197: }
198:
199: arrset(s) char s[]; {
200: fprintf( cout , "\nint %s[] {0", s );
201: arrndx = 1;
202: }
203:
204: arrval(n){
205: fprintf( cout , ",%d",n);
206: if( (++arrndx%10) == 0 ) fprintf( cout , "\n");
207: }
208:
209: arrdone(){
210: fprintf( cout , ",-1};\n");
211: }
212:
213: copy(v) char *v; { /* copy ctokn to v */
214: char *p;
215:
216: p=ctokn;
217: while( *v++ = *p++ );
218: }
219:
220: compare(v) char *v; { /* compare ctokn with v */
221: char *p;
222:
223: for( p=ctokn; ; ++p ){
224: if( *p != *v++ ) return( 0 );
225: if( *p == 0 ) return(1);
226: }
227: }
228:
229: int *yalloc(n){ /* allocate n+1 words from vector mem */
230: int *omem;
231: omem = mem;
232: mem += n+1;
233: if(mem-mem0 >= memsiz) error("memory overflow");
234: return(omem);
235: }
236:
237: aryfil( v, n, c ) int *v,n,c; { /* set elements 0 through n-1 to c */
238: int i;
239: for( i=0; i<n; ++i ) v[i] = c;
240: }
241:
242: UNION( a, b, c ) int *a, *b, *c; {
243: /* set a to the UNION of b and c */
244: /* a may equal b */
245: /* return 1 if c is not a subset of b, 0 otherwise */
246:
247: _REGISTER int i, x, sub;
248:
249: sub = 0;
250: for( i=0; i<tbitset; ++i ){
251: x = b[i] | c[i];
252: if( x != b[i] ) sub=1;
253: a[i] = x;
254: }
255: return( sub );
256: }
257:
258: prlook( p ) struct looksets *p;{
259: int j, *pp;
260: pp = p->lset;
261: if( pp == 0 ) fprintf( cout , "\tNULL");
262: else {
263: fprintf( cout , " { " );
264: for( j=1; j<=nterms; ++j ){
265: if( (pp[j>>4]>>(j&017) )&01 != 0 ) fprintf( cout , "%s ", symnam(j) );
266: }
267: fprintf( cout , "}" );
268: }
269: }
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