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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 1.2 January 1979
8: *
9: *
10: * pxp - Pascal execution profiler
11: *
12: * Bill Joy UCB
13: * Version 1.2 January 1979
14: */
15:
16: #include "0.h"
17: #include "yy.h"
18:
19: struct yytok oldpos;
20: /*
21: * The routine yyPerror coordinates the panic when
22: * the correction routines fail. Three types of panics
23: * are possible - those in a declaration part, those
24: * in a statement part, and those in an expression.
25: *
26: * Declaration part panics consider insertion of "begin",
27: * expression part panics will stop on more symbols.
28: * The panics are otherwise the same.
29: *
30: * ERROR MESSAGE SUPPRESSION STRATEGY: August 11, 1977
31: *
32: * If the parser has not made at least 2 moves since the last point of
33: * error then we want to suppress the supplied error message.
34: * Otherwise we print it.
35: * We then skip input up to the next solid symbol.
36: */
37: yyPerror(cp, kind)
38: char *cp;
39: register int kind;
40: {
41: register int ishifts, brlev;
42:
43: copy(&oldpos, &Y, sizeof oldpos);
44: brlev = 0;
45: if (yychar < 0)
46: yychar = yylex();
47: for (ishifts = yyshifts; ; yychar = yylex(), yyshifts++)
48: switch (yychar) {
49: case YILLCH:
50: yerror("Illegal character");
51: if (ishifts == yyshifts)
52: yyOshifts = 0;
53: continue;
54: case YEOF:
55: goto quiet;
56: case ';':
57: if (kind == PPROG)
58: continue;
59: if (kind == PDECL)
60: yychar = yylex();
61: goto resume;
62: case YEND:
63: if (kind == PPROG)
64: continue;
65: case YPROCEDURE:
66: case YFUNCTION:
67: goto resume;
68: case YLABEL:
69: case YTYPE:
70: case YCONST:
71: case YVAR:
72: if (kind == PSTAT) {
73: yerror("Declaration found when statement expected");
74: goto quiet;
75: }
76: case YBEGIN:
77: goto resume;
78: case YFOR:
79: case YREPEAT:
80: case YWHILE:
81: case YGOTO:
82: case YIF:
83: if (kind != PDECL)
84: goto resume;
85: yerror("Expected keyword begin after declarations, before statements");
86: unyylex(&Y);
87: yychar = YBEGIN;
88: yylval = nullsem(YBEGIN);
89: goto quiet;
90: case YTHEN:
91: case YELSE:
92: case YDO:
93: if (kind == PSTAT) {
94: yychar = yylex();
95: goto resume;
96: }
97: if (kind == PEXPR)
98: goto resume;
99: continue;
100: case ')':
101: case ']':
102: if (kind != PEXPR)
103: continue;
104: if (brlev == 0)
105: goto resume;
106: if (brlev > 0)
107: brlev--;
108: continue;
109: case '(':
110: case '[':
111: brlev++;
112: continue;
113: case ',':
114: if (brlev != 0)
115: continue;
116: case YOF:
117: case YTO:
118: case YDOWNTO:
119: if (kind == PEXPR)
120: goto resume;
121: continue;
122: #ifdef PI
123: /*
124: * A rough approximation for now
125: * Should be much more lenient on suppressing
126: * warnings.
127: */
128: case YID:
129: syneflg++;
130: continue;
131: #endif
132: }
133: resume:
134: if (yyOshifts >= 2) {
135: if (yychar != -1)
136: unyylex(&Y);
137: copy(&Y, &oldpos, sizeof Y);
138: yerror(cp);
139: yychar = yylex();
140: }
141: quiet:
142: if (yyshifts - ishifts > 2 && opt('r')) {
143: setpfx('r');
144: yerror("Parsing resumes");
145: }
146: /*
147: * If we paniced in the statement part,
148: * and didn't stop at a ';', then we insert
149: * a ';' to prevent the recovery from immediately
150: * inserting one and complaining about it.
151: */
152: if (kind == PSTAT && yychar != ';') {
153: unyylex(&Y);
154: yyshifts--;
155: yytshifts--;
156: yychar = ';';
157: yylval = nullsem(';');
158: }
159: }
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