yyerror.c

/* $Id: yyerror.c,v 4.9 2010/07/14 09:57:46 tom Exp $
 *
 * This file is included into grammar.y to provide the 'yyerror()' function.
 * If the yacc/bison parser is one that we know how to backtrack, we'll augment
 * the "syntax error" message with information that shows what type of token we
 * expected.
 */

#ifndef UCH
#define UCH(c)		((unsigned char)(c))
#endif

/* 'yyerror()' has to be a macro, since it must be expanded inline to subvert
 * the internal state of 'yyparse()'.
 */

#if BISON_HAS_YYTNAME		/* bison 1.22 */
#if !defined(YYFLAG)
#define YYFLAG YYPACT_NINF	/* yabb (yet-another-bison-bug) */
#endif
#if YYDEBUG
/* this is better than defining YYERROR_VERBOSE */
#define	yyerror(text) {\
    register int n, c1, count = 0;\
    yaccError(text);\
    if (yypact[yystate] != YYFLAG) { \
	for (c1 = 0; c1 < YYLAST; c1++) {\
	    n = yypact[yystate] + c1;\
	    if (n >= 0 && n < YYLAST\
	     && yycheck[n] == c1 && yytname[c1] != 0)\
		yaccExpected(yytname[c1], count++);\
	}\
    }\
    yaccExpected("", -1);\
}
#endif
#endif /* BISON_HAS_YYTNAME */

#if YACC_HAS_YYTOKS_2
#undef  YACC_HAS_YYTOKS
#define YACC_HAS_YYTOKS 1
#define YaccState yy_state
#endif

#if YACC_HAS_YYTOKS		/* Solaris, Gould */
#if YYDEBUG
#ifndef YaccState
#define YaccState yystate	/* sometimes 'yy_state' */
#endif
#define	yyerror(text) {\
    register int	n, x, c1, y, count = 0;\
    yaccError(text);\
    if (((n = yypact[YaccState]) > YYFLAG) && (n < YYLAST)) {\
	for (x = ((n > 0) ? n : 0); x < YYLAST; ++x) {\
	    c1 = x - n;\
	    if ((yychk[yyact[x]] == c1) && (c1 != YYERRCODE)) {\
		if (isascii(UCH(c1))) {\
		    static char tmp[] = "'%'";\
		    tmp[1] = c1;\
		    yaccExpected(tmp, count++);\
		} else {\
		    for (y = 0; yytoks[y].t_val >= 0; y++) {\
			if (yytoks[y].t_val == c1) {\
			    yaccExpected(yytoks[y].t_name, count++);\
			    break;\
			}\
		    }\
		}\
	    }\
	}\
    }\
    yaccExpected("", -1);\
}
#endif
#endif /* YACC_HAS_YYTOKS */

#if YACC_HAS_YYNAME		/* Linux's yacc */
#if YYDEBUG
#define	yyerror(text) {\
    register int n, x, c1, count = 0;\
    yaccError(text);\
    if (((n = yysindex[yystate]) != 0) && (n < YYTABLESIZE)) {\
	for (x = ((n > 0) ? n : 0); x < YYTABLESIZE; ++x) {\
	    c1 = x - n;\
	    if ((yycheck[x] == c1) && (c1 != YYERRCODE)) {\
		yaccExpected(yyname[c1] ? yyname[c1] : "illegal symbol",\
		    count++);\
	    }\
	}\
    }\
    yaccExpected("", -1);\
}
#endif
#endif /* YACC_HAS_YYNAME */

/*
 * Any way we define it, 'yyerror()' is a real function (that we provide,
 * rather than use the one from a library).
 */
static void yaccError(const char *);

#ifdef yyerror
static int
compar(const void *p1, const void *p2)
{
    const char *a = *(const char *const *) p1;
    const char *b = *(const char *const *) p2;
    return strcmp(a, b);
}

#define MSGLEN 80

static void
yaccExpected(const char *s, int count)
{
    static struct {
	const char *actual, *name;
    } tbl[] = {
	{
	    "...", "T_ELLIPSIS"
	},
	{
	    "[]", "T_BRACKETS"
	},
	{
	    "{", "T_LBRACE"
	},
	{
	    "}", "T_MATCHRBRACE"
	},
    };
    unsigned j;
    int k, x;
    unsigned n;
    const char *t = s;
    char *tt;
    const char *tag;
    char tmp[MSGLEN];

    static unsigned have;
    static unsigned used;
    static char **vec;

    if (count < 0) {
	if (used != 0) {
	    if (used > 1)
		qsort((char *) vec, used, sizeof(vec[0]), compar);
	    /* limit length of error message */
	    k = MSGLEN - (int) (strlen(vec[used - 1]) + 2);
	    for (j = 0; j < used; j++) {
		tag = j ? " " : "Expected: ";
		s = vec[j];
		if (j != (used - 1)) {
		    x = (int) (strlen(s) + strlen(tag));
		    if (k <= 0)
			continue;
		    else if ((k - x) <= 0)
			s = "...";
		    k -= x;
		}
		fprintf(stderr, "%s%s", tag, s);
	    }
	    fprintf(stderr, "\n");
	    while (used-- != 0) {
		free(vec[used]);
		vec[used] = 0;
	    }
	}
	used = 0;
    } else {
	int found = FALSE;

	strcpy(tmp, t);
	if (!strncmp(t, "T_", 2)) {
	    for (j = 0; j < sizeof(tbl) / sizeof(tbl[0]); j++) {
		if (!strcmp(t, tbl[j].name)) {
		    t = tbl[j].actual;
		    found = TRUE;
		    break;
		}
	    }
	    if (!found) {
		tt = strncpy(tmp, t + 2, sizeof(tmp) - 1);
		for (k = 0; tt[k] != '\0'; k++) {
		    if (tt[k] == '_')
			tt[k] = '-';
		    else if (isalpha(UCH(tt[k])) && isupper(UCH(tt[k])))
			tt[k] = (char) tolower(UCH(tt[k]));
		}
	    }
	}
	if ((unsigned) count >= have) {
	    have = (unsigned) (count + 10);
	    if (vec == 0) {
		vec = (char **) malloc(have * sizeof(*vec));
	    } else {
		vec = (char **) realloc(vec, have * sizeof(*vec));
	    }
	    for (n = used; n < have; n++)
		vec[n] = 0;
	}
	if (vec[count] != 0) {
	    free(vec[count]);
	}
	vec[count] = xstrdup(found ? t : tmp);
	used = (unsigned) (count + 1);
    }
}

#else
#define yyerror(s) yaccError(s)
#endif /* yyerror */