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better factor out lr table writes

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This commit is contained in:
Sven M. Hallberg 2013-06-21 20:52:27 +02:00
parent 534a29b7ba
commit d67e12a825
3 changed files with 14 additions and 9 deletions
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8
src/backends/lalr.c
View file

@ -130,10 +130,10 @@ static inline bool has_conflicts(HLRTable *table)
return !h_slist_empty(table->inadeq);
}
// place a new entry in tbl; records conflicts in tbl->inadeq
// place a new terminal entry in tbl; records conflicts in tbl->inadeq
// returns 0 on success, -1 on conflict
// ignores forall entries
int h_lrtable_put(HLRTable *tbl, size_t state, HCFChoice *x, HLRAction *action)
static int terminal_put(HLRTable *tbl, size_t state, HCFChoice *x, HLRAction *action)
{
HLRAction *prev = h_hashtable_get(tbl->rows[state], x);
if(prev && prev != action) {
@ -257,7 +257,7 @@ int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
if(fs->end_branch) {
HCFChoice *terminal = h_arena_malloc(arena, sizeof(HCFChoice));
terminal->type = HCF_END;
if(h_lrtable_put(table, state, terminal, action) < 0)
if(terminal_put(table, state, terminal, action) < 0)
inadeq = true;
}
H_FOREACH(fs->char_branches, void *key, HStringMap *m)
@ -268,7 +268,7 @@ int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
terminal->type = HCF_CHAR;
terminal->chr = key_char((HCharKey)key);
if(h_lrtable_put(table, state, terminal, action) < 0)
if(terminal_put(table, state, terminal, action) < 0)
inadeq = true;
H_END_FOREACH // lookahead character
} H_END_FOREACH // enhanced production

2
src/backends/lr.h
View file

@ -120,12 +120,10 @@ HHashValue h_hash_transition(const void *p);
HLRDFA *h_lr0_dfa(HCFGrammar *g);
HLRTable *h_lr0_table(HCFGrammar *g, const HLRDFA *dfa);
int h_lrtable_put(HLRTable *tbl, size_t state, HCFChoice *x, HLRAction *action);
int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params);
void h_lalr_free(HParser *parser);
const HLRAction *h_lr_lookup(const HLRTable *table, size_t state, const HCFChoice *symbol);
const HLRAction *h_lrengine_action(const HLREngine *engine);
void h_lrengine_step(HLREngine *engine, const HLRAction *action);
HParseResult *h_lrengine_result(HLREngine *engine);

13
src/backends/lr0.c
View file

@ -161,6 +161,14 @@ HLRDFA *h_lr0_dfa(HCFGrammar *g)
/* LR(0) table generation */
static inline
void put_shift(HLRTable *table, size_t state, const HCFChoice *symbol,
size_t nextstate)
{
HLRAction *action = h_shift_action(table->arena, nextstate);
h_hashtable_put(table->rows[state], symbol, action);
}
HLRTable *h_lr0_table(HCFGrammar *g, const HLRDFA *dfa)
{
HAllocator *mm__ = g->mm__;
@ -174,15 +182,14 @@ HLRTable *h_lr0_table(HCFGrammar *g, const HLRDFA *dfa)
// add dummy shift entry for the start symbol so h_lrengine_step can always
// find a shift.
// NB: nextstate=0 is used for the "victory condition" by h_lrengine_result.
h_hashtable_put(table->rows[0], g->start, h_shift_action(arena, 0));
put_shift(table, 0, g->start, 0);
// add shift entries
for(HSlistNode *x = dfa->transitions->head; x; x = x->next) {
// for each transition x-A->y, add "shift, goto y" to table entry (x,A)
HLRTransition *t = x->elem;
HLRAction *action = h_shift_action(arena, t->to);
h_hashtable_put(table->rows[t->from], t->symbol, action);
put_shift(table, t->from, t->symbol, t->to);
}
// add reduce entries, record inadequate states