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derp, forgot to save original nonterminal in stack frame

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Sven M. Hallberg 2013-05-11 19:26:22 +02:00
parent b6aab591ea
commit 88261f69ba
1 changed files with 12 additions and 8 deletions
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20
src/backends/llk.c
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@ -177,6 +177,9 @@ HParseResult *h_llk_parse(HAllocator* mm__, const HParser* parser, HInputStream*
// derivations are produced this linearization is unique. // derivations are produced this linearization is unique.
// the 'mark' allocated below simply reserves a memory address to use as the // the 'mark' allocated below simply reserves a memory address to use as the
// frame delimiter. // frame delimiter.
// nonterminals, instead of being popped and forgotten, are put back onto the
// stack below the mark to tell us which validations and semantic actions to
// execute on their corresponding result.
// also on the stack below the mark, we store the previously accumulated // also on the stack below the mark, we store the previously accumulated
// value for the surrounding production. // value for the surrounding production.
void *mark = h_arena_malloc(tarena, 1); void *mark = h_arena_malloc(tarena, 1);
@ -200,8 +203,7 @@ HParseResult *h_llk_parse(HAllocator* mm__, const HParser* parser, HInputStream*
// pop top of stack and check for frame delimiter // pop top of stack and check for frame delimiter
HCFChoice *x = h_slist_pop(stack); HCFChoice *x = h_slist_pop(stack);
assert(x != NULL); assert(x != NULL);
if(x == mark) if(x == mark) {
{
// hit stack frame boundary // hit stack frame boundary
// wrap the accumulated parse result, this sequence is finished // wrap the accumulated parse result, this sequence is finished
@ -210,22 +212,25 @@ HParseResult *h_llk_parse(HAllocator* mm__, const HParser* parser, HInputStream*
tok->seq = seq; tok->seq = seq;
// XXX tok->index and tok->bit_offset (don't take directly from stream, cuz peek!) // XXX tok->index and tok->bit_offset (don't take directly from stream, cuz peek!)
// recover original nonterminal and result sequence
x = h_slist_pop(stack);
seq = h_slist_pop(stack);
// tok becomes next left-most element of higher-level sequence
// call validation and semantic action, if present // call validation and semantic action, if present
if(x->pred && !x->pred(make_result(tarena, tok))) if(x->pred && !x->pred(make_result(tarena, tok)))
goto no_parse; // validation failed -> no parse goto no_parse; // validation failed -> no parse
if(x->action) if(x->action)
tok = (HParsedToken *)x->action(make_result(arena, tok)); tok = (HParsedToken *)x->action(make_result(arena, tok));
// result becomes next left-most element of higher-level sequence
seq = h_slist_pop(stack);
h_carray_append(seq, tok); h_carray_append(seq, tok);
} }
else if(x->type == HCF_CHOICE) else if(x->type == HCF_CHOICE) {
{
// x is a nonterminal; apply the appropriate production // x is a nonterminal; apply the appropriate production
// push stack frame // push stack frame
h_slist_push(stack, seq); // save current partial value h_slist_push(stack, seq); // save current partial value
h_slist_push(stack, x); // save the nonterminal
h_slist_push(stack, mark); // frame delimiter h_slist_push(stack, mark); // frame delimiter
// open a fresh result sequence // open a fresh result sequence
@ -240,8 +245,7 @@ HParseResult *h_llk_parse(HAllocator* mm__, const HParser* parser, HInputStream*
for(s--; s >= p->items; s--) for(s--; s >= p->items; s--)
h_slist_push(stack, *s); h_slist_push(stack, *s);
} }
else else {
{
// x is a terminal, or simple charset; match against input // x is a terminal, or simple charset; match against input
// consume the input token // consume the input token