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handle suspend on lookahead at the very end of the chunk

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This commit is contained in:
Sven M. Hallberg 2015-09-04 21:05:56 +02:00
parent 010a1a36ff
commit 1276004250
3 changed files with 27 additions and 14 deletions
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27
src/backends/llk.c
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@ -296,7 +296,7 @@ static HLLkState *llk_parse_start_(HAllocator* mm__, const HParser* parser)
return s;
}
// returns partial result or NULL
// returns partial result or NULL (no parse)
static HCountedArray *llk_parse_chunk_(HLLkState *s, const HParser* parser,
HInputStream* stream)
{
@ -316,6 +316,8 @@ static HCountedArray *llk_parse_chunk_(HLLkState *s, const HParser* parser,
// when we empty the stack, the parse is complete.
while(!h_slist_empty(stack)) {
tok = NULL;
// pop top of stack for inspection
x = h_slist_pop(stack);
assert(x != NULL);
@ -323,6 +325,16 @@ static HCountedArray *llk_parse_chunk_(HLLkState *s, const HParser* parser,
if(x != MARK && x->type == HCF_CHOICE) {
// x is a nonterminal; apply the appropriate production and continue
// look up applicable production in parse table
const HCFSequence *p = h_llk_lookup(table, x, stream);
if(p == NULL)
goto no_parse;
if(p == H_NEED_INPUT)
goto need_input;
// an infinite loop case that shouldn't happen
assert(!p->items[0] || p->items[0] != x);
// push stack frame
h_slist_push(stack, seq); // save current partial value
h_slist_push(stack, x); // save the nonterminal
@ -331,14 +343,6 @@ static HCountedArray *llk_parse_chunk_(HLLkState *s, const HParser* parser,
// open a fresh result sequence
seq = h_carray_new(arena);
// look up applicable production in parse table
const HCFSequence *p = h_llk_lookup(table, x, stream);
if(p == NULL)
goto no_parse;
// an infinite loop case that shouldn't happen
assert(!p->items[0] || p->items[0] != x);
// push production's rhs onto the stack (in reverse order)
HCFChoice **s;
for(s = p->items; *s; s++);
@ -433,8 +437,9 @@ static HCountedArray *llk_parse_chunk_(HLLkState *s, const HParser* parser,
need_input:
if(stream->last_chunk)
goto no_parse;
h_arena_free(arena, tok); // no result, yet
h_slist_push(stack, x); // try this symbol again next time
if(tok)
h_arena_free(arena, tok); // no result, yet
h_slist_push(stack, x); // try this symbol again next time
return seq;
}