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try to clean up and debug desugar_many

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This commit is contained in:
Sven M. Hallberg 2013-04-27 03:40:21 +02:00
parent fd10e83bfe
commit 3dfc313118
1 changed files with 33 additions and 34 deletions
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67
src/parsers/many.c
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@ -58,59 +58,58 @@ static bool many_isValidCF(void *env) {
static HCFChoice* desugar_many(HAllocator *mm__, void *env) {
HRepeat *repeat = (HRepeat*)env;
if(repeat->count > 1) {
assert_message(0, "'h_repeat_n' is not context-free, can't be desugared");
return NULL;
}
/* many(A) =>
Ma -> A Mar
-> \epsilon (but not if many1/sepBy1 is used)
Mar -> Sep A Mar
-> \epsilon
*/
HCFChoice *ret = h_new(HCFChoice, 1);
ret->type = HCF_CHOICE;
if (repeat->min_p)
ret->seq = h_new(HCFSequence*, 2); /* choice of 1 sequence, A Mar */
else
ret->seq = h_new(HCFSequence*, 3); /* choice of 2 sequences, A Mar | epsilon */
ret->seq[0] = h_new(HCFSequence, 1);
ret->seq[0]->items = h_new(HCFChoice*, 2);
HCFChoice *a = h_desugar(mm__, repeat->p);
HCFChoice *ma = h_new(HCFChoice, 1);
HCFChoice *mar = h_new(HCFChoice, 1);
HCFChoice *eps = desugar_epsilon(mm__, NULL);
/* create first subrule */
HCFChoice *ma = h_new(HCFChoice, 3);
ma->type = HCF_CHOICE;
ma->seq[0]->items[0] = h_desugar(mm__, repeat->p);
ma->seq = h_new(HCFSequence*, 3); /* enough for 2 productions */
ma->seq[0] = h_new(HCFSequence, 1);
ma->seq[0]->items = h_new(HCFChoice*, 3);
ma->seq[0]->items[0] = a;
ma->seq[0]->items[1] = mar;
ma->seq[0]->items[2] = NULL;
ma->seq[1] = NULL;
/* if not many1/sepBy1, attach epsilon */
if (repeat->count == 0) {
ma->seq[1] = h_new(HCFSequence, 1);
ma->seq[1]->items = h_new(HCFChoice*, 2);
ma->seq[1]->items[0] = eps;
ma->seq[1]->items[1] = NULL;
ma->seq[2] = NULL;
}
/* create second subrule */
HCFChoice *mar = h_new(HCFChoice, 3);
mar->type = HCF_CHOICE;
mar->seq = h_new(HCFSequence*, 2);
mar->seq = h_new(HCFSequence*, 3);
mar->seq[0] = h_new(HCFSequence, 1);
mar->seq[0]->items = h_new(HCFChoice*, 4);
mar->seq[0]->items[0] = h_desugar(mm__, repeat->sep);
mar->seq[0]->items[1] = h_desugar(mm__, repeat->p);
mar->seq[0]->items[1] = a;
mar->seq[0]->items[2] = mar; // woo recursion!
mar->seq[0]->items[3] = NULL;
mar->seq[1] = h_new(HCFSequence, 1);
mar->seq[1]->items = h_new(HCFChoice*, 2);
mar->seq[1]->items[0] = desugar_epsilon(mm__, NULL);\
mar->seq[1]->items[0] = eps;
mar->seq[1]->items[1] = NULL;
mar->seq[2]->items = NULL;
mar->seq[2] = NULL;
/* attach second subrule to first subrule */
ma->seq[0]->items[1] = mar;
ma->seq[0]->items[2] = NULL;
/* attach first subrule to ret */
ret->seq[0]->items[0] = ma;
ret->seq[0]->items[1] = NULL;
/* if not many1/sepBy1, attach epsilon */
if (repeat->min_p) {
ret->seq[1]->items = NULL;
} else {
ret->seq[1]->items = h_new(HCFChoice*, 2);
ret->seq[1]->items[0] = desugar_epsilon(mm__, NULL);
ret->seq[1]->items[1] = NULL;
ret->seq[2]->items = NULL;
}
return ret;
return ma;
}
static const HParserVtable many_vt = {