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1.1 root 1: /* Copyright (c) 1979 Regents of the University of California */
2: #
3: /*
4: * pi - Pascal interpreter code translator
5: *
6: * Charles Haley, Bill Joy UCB
7: * Version 1.1 February 1978
8: *
9: *
10: * pxp - Pascal execution profiler
11: *
12: * Bill Joy UCB
13: * Version 1.1 February 1978
14: */
15:
16: #include "whoami"
17: #include "0.h"
18: #include "yy.h"
19:
20: struct yytok oldpos;
21: /*
22: * The routine yyPerror coordinates the panic when
23: * the correction routines fail. Three types of panics
24: * are possible - those in a declaration part, those
25: * in a statement part, and those in an expression.
26: *
27: * Declaration part panics consider insertion of "begin",
28: * expression part panics will stop on more symbols.
29: * The panics are otherwise the same.
30: *
31: * ERROR MESSAGE SUPPRESSION STRATEGY: August 11, 1977
32: *
33: * If the parser has not made at least 2 moves since the last point of
34: * error then we want to suppress the supplied error message.
35: * Otherwise we print it.
36: * We then skip input up to the next solid symbol.
37: */
38: yyPerror(cp, kind)
39: char *cp;
40: register int kind;
41: {
42: register int ishifts, brlev;
43:
44: copy(&oldpos, &Y, sizeof oldpos);
45: brlev = 0;
46: if (yychar < 0)
47: yychar = yylex();
48: for (ishifts = yyshifts; ; yychar = yylex(), yyshifts++)
49: switch (yychar) {
50: case YILLCH:
51: yerror("Illegal character");
52: if (ishifts == yyshifts)
53: yyOshifts = 0;
54: continue;
55: case YEOF:
56: goto quiet;
57: case ';':
58: if (kind == PPROG)
59: continue;
60: if (kind == PDECL)
61: yychar = yylex();
62: goto resume;
63: case YEND:
64: if (kind == PPROG)
65: continue;
66: case YPROCEDURE:
67: case YFUNCTION:
68: goto resume;
69: case YLABEL:
70: case YTYPE:
71: case YCONST:
72: case YVAR:
73: if (kind == PSTAT) {
74: yerror("Declaration found when statement expected");
75: goto quiet;
76: }
77: case YBEGIN:
78: goto resume;
79: case YFOR:
80: case YREPEAT:
81: case YWHILE:
82: case YGOTO:
83: case YIF:
84: if (kind != PDECL)
85: goto resume;
86: yerror("Expected keyword begin after declarations, before statements");
87: unyylex(&Y);
88: yychar = YBEGIN;
89: yylval = nullsem(YBEGIN);
90: goto quiet;
91: case YTHEN:
92: case YELSE:
93: case YDO:
94: if (kind == PSTAT) {
95: yychar = yylex();
96: goto resume;
97: }
98: if (kind == PEXPR)
99: goto resume;
100: continue;
101: case ')':
102: case ']':
103: if (kind != PEXPR)
104: continue;
105: if (brlev == 0)
106: goto resume;
107: if (brlev > 0)
108: brlev--;
109: continue;
110: case '(':
111: case '[':
112: brlev++;
113: continue;
114: case ',':
115: if (brlev != 0)
116: continue;
117: case YOF:
118: case YTO:
119: case YDOWNTO:
120: if (kind == PEXPR)
121: goto resume;
122: continue;
123: #ifdef PI
124: /*
125: * A rough approximation for now
126: * Should be much more lenient on suppressing
127: * warnings.
128: */
129: case YID:
130: syneflg++;
131: continue;
132: #endif
133: }
134: resume:
135: if (yyOshifts >= 2) {
136: if (yychar != -1)
137: unyylex(&Y);
138: copy(&Y, &oldpos, sizeof Y);
139: yerror(cp);
140: yychar = yylex();
141: }
142: quiet:
143: if (yyshifts - ishifts > 2 && opt('r')) {
144: setpfx('r');
145: yerror("Parsing resumes");
146: }
147: /*
148: * If we paniced in the statement part,
149: * and didn't stop at a ';', then we insert
150: * a ';' to prevent the recovery from immediately
151: * inserting one and complaining about it.
152: */
153: if (kind == PSTAT && yychar != ';') {
154: unyylex(&Y);
155: yyshifts--;
156: yytshifts--;
157: yychar = ';';
158: yylval = nullsem(';');
159: }
160: }
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