[unix-history] / .ref-BSD-1 / pxp / yypanic.c

#
/*
 * pi - Pascal interpreter code translator
 *
 * Charles Haley, Bill Joy UCB
 * Version 1.0 August 1977
 *
 *
 * pxp - Pascal execution profiler
 *
 * Bill Joy UCB
 * Version 1.0 August 1977
 */

#include "whoami"
#include "0.h"
#include "yy.h"


/*
 * The routine yyPerror coordinates the panic when
 * the correction routines fail. Three types of panics
 * are possible - those in a declaration part, those
 * in a statement part, and those in an expression.
 *
 * Declaration part panics consider insertion of "begin",
 * expression part panics will stop on more symbols.
 * The panics are otherwise the same.
 *
 * ERROR MESSAGE SUPPRESSION STRATEGY: August 11, 1977
 *
 * If the parser has not made at least 2 moves since the last point of
 * error then we want to suppress the supplied error message.
 * Otherwise we print it.
 * We then skip input up to the next solid symbol.
 */
yyPerror(cp, kind)
	char *cp;
	int kind;
{
	struct yytok oldpos;
	int ishifts, brlev;

	copy(&oldpos, &Y, sizeof oldpos);
	brlev = 0;
	for (ishifts = yyshifts; ; yychar = yylex(), yyshifts++)
		switch (yychar) {
			case YILLCH:
				yerror("Illegal character");
				if (ishifts == yyshifts)
					yyOshifts = 0;
				continue;
			case YEOF:
				goto quiet;
			case ';':
				if (kind == PPROG)
					continue;
				if (kind == PDECL)
					yychar = yylex();
				goto resume;
			case YEND:
				if (kind == PPROG)
					continue;
			case YPROCEDURE:
			case YFUNCTION:
				goto resume;
			case YLABEL:
			case YTYPE:
			case YCONST:
			case YVAR:
				if (kind == PSTAT) {
					yerror("Declaration found when statement expected");
					goto quiet;
				}
			case YBEGIN:
				goto resume;
			case YFOR:
			case YREPEAT:
			case YWHILE:
			case YGOTO:
			case YIF:
				if (kind != PDECL)
					goto resume;
				yerror("Expected keyword begin after declarations, before statements");
				unyylex(&Y);
				yychar = YBEGIN;
				yylval = nullsem(YBEGIN);
				goto quiet;
			case YTHEN:
			case YELSE:
			case YDO:
				if (kind == PSTAT) {
					yychar = yylex();
					goto resume;
				}
				if (kind == PEXPR)
					goto resume;
				continue;
			case ')':
			case ']':
				if (kind != PEXPR)
					continue;
				if (brlev == 0)
					goto resume;
				if (brlev > 0)
					brlev--;
				continue;
			case '(':
			case '[':
				brlev++;
				continue;
			case ',':
				if (brlev != 0)
					continue;
			case YOF:
			case YTO:
			case YDOWNTO:
				if (kind == PEXPR)
					goto resume;
				continue;
#ifdef PI
			/*
			 * A rough approximation for now
			 * Should be much more lenient on suppressing
			 * warnings.
			 */
			case YID:
				syneflg++;
				continue;
#endif
		}
resume:
	if (yyOshifts >= 2) {
		if (yychar != -1)
			unyylex(&Y);
		copy(&Y, &oldpos, sizeof Y);
		yerror(cp);
		yychar = yylex();
	}
quiet:
	if (yyshifts - ishifts > 2 && opt('r')) {
		setpfx('r');
		yerror("Parsing resumes");
	}
	/*
	 * If we paniced in the statement part,
	 * and didn't stop at a ';', then we insert
	 * a ';' to prevent the recovery from immediately
	 * inserting one and complaining about it.
	 */
	if (kind == PSTAT && yychar != ';') {
		unyylex(&Y);
		yyshifts--;
		yytshifts--;
		yychar = ';';
		yylval = nullsem(';');
	}
}
Commit	Line	Data
8ca692a3 CH	1	#
	2	/*
	3	* pi - Pascal interpreter code translator
	4	*
	5	* Charles Haley, Bill Joy UCB
	6	* Version 1.0 August 1977
	7	*
	8	*
	9	* pxp - Pascal execution profiler
	10	*
	11	* Bill Joy UCB
	12	* Version 1.0 August 1977
	13	*/
	14
	15	#include "whoami"
	16	#include "0.h"
	17	#include "yy.h"
	18
	19
	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	int kind;
	40	{
	41	struct yytok oldpos;
	42	int ishifts, brlev;
	43
	44	copy(&oldpos, &Y, sizeof oldpos);
	45	brlev = 0;
	46	for (ishifts = yyshifts; ; yychar = yylex(), yyshifts++)
	47	switch (yychar) {
	48	case YILLCH:
	49	yerror("Illegal character");
	50	if (ishifts == yyshifts)
	51	yyOshifts = 0;
	52	continue;
	53	case YEOF:
	54	goto quiet;
	55	case ';':
	56	if (kind == PPROG)
	57	continue;
	58	if (kind == PDECL)
	59	yychar = yylex();
	60	goto resume;
	61	case YEND:
	62	if (kind == PPROG)
	63	continue;
	64	case YPROCEDURE:
65	case YFUNCTION:
66	goto resume;
67	case YLABEL:
68	case YTYPE:
69	case YCONST:
70	case YVAR:
71	if (kind == PSTAT) {
72	yerror("Declaration found when statement expected");
73	goto quiet;
74	}
75	case YBEGIN:
76	goto resume;
77	case YFOR:
78	case YREPEAT:
79	case YWHILE:
80	case YGOTO:
81	case YIF:
82	if (kind != PDECL)
83	goto resume;
84	yerror("Expected keyword begin after declarations, before statements");
85	unyylex(&Y);
86	yychar = YBEGIN;
87	yylval = nullsem(YBEGIN);
88	goto quiet;
89	case YTHEN:
90	case YELSE:
91	case YDO:
92	if (kind == PSTAT) {
93	yychar = yylex();
94	goto resume;
95	}
96	if (kind == PEXPR)
97	goto resume;
98	continue;
99	case ')':
100	case ']':
101	if (kind != PEXPR)
102	continue;
103	if (brlev == 0)
104	goto resume;
105	if (brlev > 0)
106	brlev--;
107	continue;
108	case '(':
109	case '[':
110	brlev++;
111	continue;
112	case ',':
113	if (brlev != 0)
114	continue;
115	case YOF:
116	case YTO:
117	case YDOWNTO:
118	if (kind == PEXPR)
119	goto resume;
120	continue;
121	#ifdef PI
122	/*
123	* A rough approximation for now
124	* Should be much more lenient on suppressing
125	* warnings.
126	*/
127	case YID:
128	syneflg++;
129	continue;
130	#endif
131	}
132	resume:
133	if (yyOshifts >= 2) {
134	if (yychar != -1)
135	unyylex(&Y);
136	copy(&Y, &oldpos, sizeof Y);
137	yerror(cp);
138	yychar = yylex();
139	}
140	quiet:
141	if (yyshifts - ishifts > 2 && opt('r')) {
142	setpfx('r');
143	yerror("Parsing resumes");
144	}
145	/*
146	* If we paniced in the statement part,
147	* and didn't stop at a ';', then we insert
148	* a ';' to prevent the recovery from immediately
149	* inserting one and complaining about it.
150	*/
151	if (kind == PSTAT && yychar != ';') {
152	unyylex(&Y);
153	yyshifts--;
154	yytshifts--;
155	yychar = ';';
156	yylval = nullsem(';');
157	}
158	}