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#include "parse.h"
#include "fn.h"
#include "errloc.h"
#include "lex.h"
#include "lit.h"
#include "prv.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
void ast_free(struct ast *ast)
{
for (struct lit *l = ast->lits, *next; l; l = next)
{
next = l->next;
lit_free(l);
free(l);
}
for (size_t i = 0; i < ast->nfns; i++)
fn_free(&ast->fns[i]);
free(ast->fns);
}
static const char *expected(const struct step *s)
{
static const char *tmap[] =
{
[ID] = "identifier", [LIT] = "literal", [NUM] = "number"
};
return s->id ? s->id : tmap[s->type];
}
static int iter(const struct lex *l, struct prv *p)
{
struct pos *pos = p->pos;
const struct step *s;
const struct tk *tk = p->tk;
if (!pos)
return lex_eof(l, tk) ? 0 : fn(l, p);
pos = &p->pos[p->i];
if (!(s = pos->step))
{
if (lex_eof(l, tk))
return 0;
else if (p->n > 1)
return pop(l, p) ? -1 : 1;
else
{
switch (tk->type)
{
case LIT:
errloc(tk, "unexpected literal \"%s\"", tk->s);
break;
case NUM:
errloc(tk, "unexpected number %s", tk->s);
break;
case ID:
errloc(tk, "unexpected %s %s", kw(tk->s) ?
"keyword" : "identifier", tk->s);
break;
case ANY:
case UNDEF:
errloc(tk, "%s: unreachable", __func__);
break;
}
return -1;
}
}
else if (lex_eof(l, tk))
{
if (p->stk == p->tk)
return pop(l, p) ? -1 : 1;
else if (s->type)
{
tk--;
if (lex_eof(l, p->stk))
{
errloc(tk, "expected %s", expected(pos->step));
return -1;
}
}
}
if (!s->type)
return pos->seq->fn(l, p);
else if ((s->type == ID || s->type == ANY) && !s->id && kw(tk->s)
&& !s->chain)
{
if (tk != p->stk || !p->n)
{
errloc(tk, "unexpected keyword %s", tk->s);
return -1;
}
else if (pop(l, p))
return -1;
pos = &p->pos[p->i];
}
else if ((s->type != tk->type && s->type != ANY)
|| (s->type == ID && s->id && strcmp(s->id, tk->s))
|| (s->type == ID && kw(tk->s) && s->chain))
{
pos->step = (++pos->seq)->steps;
p->tk = p->stk;
}
else
{
const struct tk *next = tk + 1;
if (!s->chain)
pos->step++;
else if (!lex_eof(l, next))
{
if (s->chain && kw(next->s))
pos->step++;
}
else
pos->step++;
p->tk++;
}
return 1;
}
static void free_prv(struct prv *p)
{
free(p->levels);
free(p->pos);
}
int parse(const struct lex *l, struct ast *ast)
{
int ret;
struct prv prv = {0};
prv.ast = ast;
if (!(prv.tk = l->tokens))
return 0;
while ((ret = iter(l, &prv)) > 0)
;
free_prv(&prv);
return ret;
}
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