cpython/Parser/grammar.c

/* Grammar implementation */

#include <stdio.h>
#include <ctype.h>

#include "PROTO.h"
#include "malloc.h"
#include "assert.h"
#include "token.h"
#include "grammar.h"

extern int debugging;

grammar *
newgrammar(start)
	int start;
{
	grammar *g;
	
	g = NEW(grammar, 1);
	if (g == NULL)
		fatal("no mem for new grammar");
	g->g_ndfas = 0;
	g->g_dfa = NULL;
	g->g_start = start;
	g->g_ll.ll_nlabels = 0;
	g->g_ll.ll_label = NULL;
	return g;
}

dfa *
adddfa(g, type, name)
	grammar *g;
	int type;
	char *name;
{
	dfa *d;
	
	RESIZE(g->g_dfa, dfa, g->g_ndfas + 1);
	if (g->g_dfa == NULL)
		fatal("no mem to resize dfa in adddfa");
	d = &g->g_dfa[g->g_ndfas++];
	d->d_type = type;
	d->d_name = name;
	d->d_nstates = 0;
	d->d_state = NULL;
	d->d_initial = -1;
	d->d_first = NULL;
	return d; /* Only use while fresh! */
}

int
addstate(d)
	dfa *d;
{
	state *s;
	
	RESIZE(d->d_state, state, d->d_nstates + 1);
	if (d->d_state == NULL)
		fatal("no mem to resize state in addstate");
	s = &d->d_state[d->d_nstates++];
	s->s_narcs = 0;
	s->s_arc = NULL;
	return s - d->d_state;
}

void
addarc(d, from, to, lbl)
	dfa *d;
	int lbl;
{
	state *s;
	arc *a;
	
	assert(0 <= from && from < d->d_nstates);
	assert(0 <= to && to < d->d_nstates);
	
	s = &d->d_state[from];
	RESIZE(s->s_arc, arc, s->s_narcs + 1);
	if (s->s_arc == NULL)
		fatal("no mem to resize arc list in addarc");
	a = &s->s_arc[s->s_narcs++];
	a->a_lbl = lbl;
	a->a_arrow = to;
}

int
addlabel(ll, type, str)
	labellist *ll;
	int type;
	char *str;
{
	int i;
	label *lb;
	
	for (i = 0; i < ll->ll_nlabels; i++) {
		if (ll->ll_label[i].lb_type == type &&
			strcmp(ll->ll_label[i].lb_str, str) == 0)
			return i;
	}
	RESIZE(ll->ll_label, label, ll->ll_nlabels + 1);
	if (ll->ll_label == NULL)
		fatal("no mem to resize labellist in addlabel");
	lb = &ll->ll_label[ll->ll_nlabels++];
	lb->lb_type = type;
	lb->lb_str = str; /* XXX strdup(str) ??? */
	return lb - ll->ll_label;
}

/* Same, but rather dies than adds */

int
findlabel(ll, type, str)
	labellist *ll;
	int type;
	char *str;
{
	int i;
	label *lb;
	
	for (i = 0; i < ll->ll_nlabels; i++) {
		if (ll->ll_label[i].lb_type == type /*&&
			strcmp(ll->ll_label[i].lb_str, str) == 0*/)
			return i;
	}
	fprintf(stderr, "Label %d/'%s' not found\n", type, str);
	abort();
}

static void
translabel(g, lb)
	grammar *g;
	label *lb;
{
	int i;
	
	if (debugging)
		printf("Translating label %s ...\n", labelrepr(lb));
	
	if (lb->lb_type == NAME) {
		for (i = 0; i < g->g_ndfas; i++) {
			if (strcmp(lb->lb_str, g->g_dfa[i].d_name) == 0) {
				if (debugging)
					printf("Label %s is non-terminal %d.\n",
						lb->lb_str,
						g->g_dfa[i].d_type);
				lb->lb_type = g->g_dfa[i].d_type;
				lb->lb_str = NULL;
				return;
			}
		}
		for (i = 0; i < (int)N_TOKENS; i++) {
			if (strcmp(lb->lb_str, tok_name[i]) == 0) {
				if (debugging)
					printf("Label %s is terminal %d.\n",
						lb->lb_str, i);
				lb->lb_type = i;
				lb->lb_str = NULL;
				return;
			}
		}
		printf("Can't translate NAME label '%s'\n", lb->lb_str);
		return;
	}
	
	if (lb->lb_type == STRING) {
		if (isalpha(lb->lb_str[1])) {
			char *p, *strchr();
			if (debugging)
				printf("Label %s is a keyword\n", lb->lb_str);
			lb->lb_type = NAME;
			lb->lb_str++;
			p = strchr(lb->lb_str, '\'');
			if (p)
				*p = '\0';
		}
		else {
			if (lb->lb_str[2] == lb->lb_str[0]) {
				int type = (int) tok_1char(lb->lb_str[1]);
				if (type != OP) {
					lb->lb_type = type;
					lb->lb_str = NULL;
				}
				else
					printf("Unknown OP label %s\n",
						lb->lb_str);
			}
			else
				printf("Can't translate STRING label %s\n",
					lb->lb_str);
		}
	}
	else
		printf("Can't translate label '%s'\n", labelrepr(lb));
}

void
translatelabels(g)
	grammar *g;
{
	int i;
	
	printf("Translating labels ...\n");
	/* Don't translate EMPTY */
	for (i = EMPTY+1; i < g->g_ll.ll_nlabels; i++)
		translabel(g, &g->g_ll.ll_label[i]);
}