LALR example parses!
This commit is contained in:
Sven M. Hallberg
parent
bfc2433320
commit
06acbe2fb5
1 changed files with 107 additions and 80 deletions
|
|
@ -56,6 +56,7 @@ typedef struct HLREnhGrammar_ {
|
|||
HCFGrammar *grammar; // enhanced grammar
|
||||
HHashTable *tmap; // maps transitions to enhanced-grammar symbols
|
||||
HHashTable *smap; // maps enhanced-grammar symbols to transitions
|
||||
HHashTable *corr; // maps symbols to sets of corresponding e. symbols
|
||||
HArena *arena;
|
||||
} HLREnhGrammar;
|
||||
|
||||
|
|
@ -441,6 +442,7 @@ HLRTable *h_lr0_table(HCFGrammar *g, const HLRDFA *dfa)
|
|||
// find reducible items in state
|
||||
H_FOREACH_KEY(dfa->states[i], HLRItem *item)
|
||||
if(item->mark == item->len) { // mark at the end
|
||||
// check for conflicts
|
||||
// XXX store more informative stuff in the inadeq records?
|
||||
if(table->forall[i]) {
|
||||
// reduce/reduce conflict with a previous item
|
||||
|
|
@ -448,11 +450,11 @@ HLRTable *h_lr0_table(HCFGrammar *g, const HLRDFA *dfa)
|
|||
} else if(!h_hashtable_empty(table->rows[i])) {
|
||||
// shift/reduce conflict with one of the row's entries
|
||||
h_slist_push(table->inadeq, (void *)(uintptr_t)i);
|
||||
} else {
|
||||
}
|
||||
|
||||
// set reduce action for the entire row
|
||||
table->forall[i] = reduce_action(arena, item);
|
||||
}
|
||||
}
|
||||
H_END_FOREACH
|
||||
}
|
||||
|
||||
|
|
@ -478,39 +480,6 @@ static size_t follow_transition(const HLRTable *table, size_t x, HCFChoice *A)
|
|||
return action->nextstate;
|
||||
}
|
||||
|
||||
static HCFChoice *transform_symbol(const HLRTable *table, HLREnhGrammar *eg,
|
||||
size_t x, HCFChoice *B, size_t z);
|
||||
|
||||
static HCFChoice *transform_productions(const HLRTable *table, HLREnhGrammar *eg,
|
||||
size_t x, HCFChoice *xAy)
|
||||
{
|
||||
HArena *arena = eg->arena;
|
||||
|
||||
HCFSequence **seq = h_arena_malloc(arena, seqsize(xAy->seq)
|
||||
* sizeof(HCFSequence *));
|
||||
HCFSequence **p, **q;
|
||||
for(p=xAy->seq, q=seq; *p; p++, q++) {
|
||||
// trace rhs starting in state x and following the transitions
|
||||
// xAy -> xBz ...
|
||||
|
||||
HCFChoice **B = (*p)->items;
|
||||
HCFChoice **xBz = h_arena_malloc(arena, seqsize(B) * sizeof(HCFChoice *));
|
||||
for(; *B; B++, xBz++) {
|
||||
size_t z = follow_transition(table, x, *B);
|
||||
*xBz = transform_symbol(table, eg, x, *B, z);
|
||||
x=z;
|
||||
}
|
||||
*xBz = NULL;
|
||||
|
||||
*q = h_arena_malloc(arena, sizeof(HCFSequence));
|
||||
(*q)->items = xBz;
|
||||
}
|
||||
*q = NULL;
|
||||
xAy->seq = seq;
|
||||
|
||||
return xAy; // pass-through
|
||||
}
|
||||
|
||||
static inline HLRTransition *transition(HArena *arena,
|
||||
size_t x, const HCFChoice *A, size_t y)
|
||||
{
|
||||
|
|
@ -521,51 +490,101 @@ static inline HLRTransition *transition(HArena *arena,
|
|||
return t;
|
||||
}
|
||||
|
||||
static HCFChoice *transform_symbol(const HLRTable *table, HLREnhGrammar *eg,
|
||||
size_t x, HCFChoice *B, size_t z)
|
||||
// no-op on terminal symbols
|
||||
static void transform_productions(const HLRTable *table, HLREnhGrammar *eg,
|
||||
size_t x, HCFChoice *xAy)
|
||||
{
|
||||
if(xAy->type != HCF_CHOICE)
|
||||
return;
|
||||
// XXX CHARSET?
|
||||
|
||||
HArena *arena = eg->arena;
|
||||
|
||||
// look up the transition in map, create symbol if not found
|
||||
HLRTransition *x_B_z = transition(arena, x, B, z);
|
||||
HCFChoice *xBz = h_hashtable_get(eg->tmap, x_B_z);
|
||||
if(!xBz) {
|
||||
HCFChoice *xBz = h_arena_malloc(arena, sizeof(HCFChoice));
|
||||
*xBz = *B;
|
||||
h_hashtable_put(eg->tmap, x_B_z, xBz);
|
||||
h_hashtable_put(eg->smap, xBz, x_B_z);
|
||||
}
|
||||
HCFSequence **seq = h_arena_malloc(arena, seqsize(xAy->seq)
|
||||
* sizeof(HCFSequence *));
|
||||
HCFSequence **p, **q;
|
||||
for(p=xAy->seq, q=seq; *p; p++, q++) {
|
||||
// trace rhs starting in state x and following the transitions
|
||||
// xAy -> ... iBj ...
|
||||
|
||||
return transform_productions(table, eg, x, xBz);
|
||||
size_t i = x;
|
||||
HCFChoice **B = (*p)->items;
|
||||
HCFChoice **items = h_arena_malloc(arena, seqsize(B) * sizeof(HCFChoice *));
|
||||
HCFChoice **iBj = items;
|
||||
for(; *B; B++, iBj++) {
|
||||
size_t j = follow_transition(table, i, *B);
|
||||
HLRTransition *i_B_j = transition(arena, i, *B, j);
|
||||
*iBj = h_hashtable_get(eg->tmap, i_B_j);
|
||||
assert(*iBj != NULL);
|
||||
i = j;
|
||||
}
|
||||
*iBj = NULL;
|
||||
|
||||
*q = h_arena_malloc(arena, sizeof(HCFSequence));
|
||||
(*q)->items = items;
|
||||
}
|
||||
*q = NULL;
|
||||
xAy->seq = seq;
|
||||
}
|
||||
|
||||
static bool eq_transition(const void *p, const void *q)
|
||||
{
|
||||
const HLRTransition *a=p, *b=q;
|
||||
return (a->from == b->from && a->to == b->to && a->symbol == b->symbol);
|
||||
return (a->from == b->from && a->to == b->to && eq_symbol(a->symbol, b->symbol));
|
||||
}
|
||||
|
||||
static HHashValue hash_transition(const void *p)
|
||||
{
|
||||
const HLRTransition *t = p;
|
||||
return (h_hash_ptr(t->symbol) + t->from + t->to); // XXX ?
|
||||
return (hash_symbol(t->symbol) + t->from + t->to); // XXX ?
|
||||
}
|
||||
|
||||
static HLREnhGrammar *enhance_grammar(const HCFGrammar *g, const HLRTable *tbl)
|
||||
HCFChoice *new_enhanced_symbol(HLREnhGrammar *eg, const HCFChoice *sym)
|
||||
{
|
||||
HArena *arena = eg->arena;
|
||||
HCFChoice *esym = h_arena_malloc(arena, sizeof(HCFChoice));
|
||||
*esym = *sym;
|
||||
|
||||
HHashSet *cs = h_hashtable_get(eg->corr, sym);
|
||||
if(!cs) {
|
||||
cs = h_hashset_new(arena, eq_symbol, hash_symbol);
|
||||
h_hashtable_put(eg->corr, sym, cs);
|
||||
}
|
||||
h_hashset_put(cs, esym);
|
||||
|
||||
return esym;
|
||||
}
|
||||
static HLREnhGrammar *enhance_grammar(const HCFGrammar *g, const HLRDFA *dfa,
|
||||
const HLRTable *table)
|
||||
{
|
||||
HAllocator *mm__ = g->mm__;
|
||||
HArena *arena = g->arena; // XXX ?
|
||||
|
||||
HLREnhGrammar *eg = h_arena_malloc(arena, sizeof(HLREnhGrammar));
|
||||
eg->tmap = h_hashtable_new(arena, eq_transition, hash_transition);
|
||||
eg->smap = h_hashtable_new(arena, eq_transition, hash_transition);
|
||||
eg->smap = h_hashtable_new(arena, eq_symbol, hash_symbol);
|
||||
eg->corr = h_hashtable_new(arena, eq_symbol, hash_symbol);
|
||||
eg->arena = arena;
|
||||
|
||||
// copy the start symbol over
|
||||
HCFChoice *start = h_arena_malloc(arena, sizeof(HCFChoice));
|
||||
*start = *(g->start);
|
||||
// establish mapping between transitions and symbols
|
||||
for(HSlistNode *x=dfa->transitions->head; x; x=x->next) {
|
||||
HLRTransition *t = x->elem;
|
||||
|
||||
transform_productions(tbl, eg, 0, start);
|
||||
assert(!h_hashtable_present(eg->tmap, t));
|
||||
|
||||
HCFChoice *sym = new_enhanced_symbol(eg, t->symbol);
|
||||
h_hashtable_put(eg->tmap, t, sym);
|
||||
h_hashtable_put(eg->smap, sym, t);
|
||||
}
|
||||
|
||||
// transform the productions
|
||||
H_FOREACH(eg->tmap, HLRTransition *t, HCFChoice *sym)
|
||||
transform_productions(table, eg, t->from, sym);
|
||||
H_END_FOREACH
|
||||
|
||||
// add the start symbol
|
||||
HCFChoice *start = new_enhanced_symbol(eg, g->start);
|
||||
transform_productions(table, eg, 0, start);
|
||||
|
||||
eg->grammar = h_cfgrammar_(mm__, start);
|
||||
return eg;
|
||||
|
|
@ -638,7 +657,7 @@ int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
|
|||
if(has_conflicts(table)) {
|
||||
HArena *arena = table->arena;
|
||||
|
||||
HLREnhGrammar *eg = enhance_grammar(g, table);
|
||||
HLREnhGrammar *eg = enhance_grammar(g, dfa, table);
|
||||
if(eg == NULL) { // this should normally not happen
|
||||
h_cfgrammar_free(g);
|
||||
h_lrtable_free(table);
|
||||
|
|
@ -664,10 +683,10 @@ int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
|
|||
HLRAction *action = reduce_action(arena, item);
|
||||
|
||||
// find all LR(0)-enhanced productions matching item
|
||||
H_FOREACH(eg->smap, HCFChoice *lhs, HLRTransition *t)
|
||||
if(t->symbol != item->lhs)
|
||||
continue;
|
||||
assert(lhs->type == HCF_CHOICE); // XXX could be CHARSET
|
||||
HHashSet *lhss = h_hashtable_get(eg->corr, item->lhs);
|
||||
assert(lhss != NULL);
|
||||
H_FOREACH_KEY(lhss, HCFChoice *lhs)
|
||||
assert(lhs->type == HCF_CHOICE); // XXX could be CHARSET?
|
||||
|
||||
for(HCFSequence **p=lhs->seq; *p; p++) {
|
||||
HCFChoice **rhs = (*p)->items;
|
||||
|
|
@ -952,11 +971,13 @@ void h_pprint_lrtable(FILE *f, const HCFGrammar *g, const HLRTable *table,
|
|||
for(size_t i=0; i<table->nrows; i++) {
|
||||
for(unsigned int j=0; j<indent; j++) fputc(' ', f);
|
||||
fprintf(f, "%4lu:", i);
|
||||
if(table->forall[i] && h_hashtable_empty(table->rows[i])) {
|
||||
if(table->forall[i]) {
|
||||
fputs(" - ", f);
|
||||
pprint_lraction(f, g, table->forall[i]);
|
||||
fputs(" -", f);
|
||||
} else {
|
||||
if(!h_hashtable_empty(table->rows[i]))
|
||||
fputs(" !!", f);
|
||||
}
|
||||
H_FOREACH(table->rows[i], HCFChoice *symbol, HLRAction *action)
|
||||
fputc(' ', f); // separator
|
||||
h_pprint_symbol(f, g, symbol);
|
||||
|
|
@ -969,9 +990,16 @@ void h_pprint_lrtable(FILE *f, const HCFGrammar *g, const HLRTable *table,
|
|||
pprint_lraction(f, g, action);
|
||||
}
|
||||
H_END_FOREACH
|
||||
}
|
||||
fputc('\n', f);
|
||||
}
|
||||
|
||||
#if 0
|
||||
fputs("inadeq=", f);
|
||||
for(HSlistNode *x=table->inadeq->head; x; x=x->next) {
|
||||
fprintf(f, "%lu ", (uintptr_t)x->elem);
|
||||
}
|
||||
fputc('\n', f);
|
||||
#endif
|
||||
}
|
||||
|
||||
|
||||
|
|
@ -993,13 +1021,12 @@ int test_lalr(void)
|
|||
E -> E '-' T
|
||||
| T
|
||||
T -> '(' E ')'
|
||||
| N
|
||||
N -> '0' -- also try [0-9] for the charset paths
|
||||
| 'n' -- also try [0-9] for the charset paths
|
||||
*/
|
||||
|
||||
HParser *N = h_sequence(h_ch('n'), NULL);
|
||||
HParser *n = h_ch('n');
|
||||
HParser *E = h_indirect();
|
||||
HParser *T = h_choice(h_sequence(h_ch('('), E, h_ch(')'), NULL), N, NULL);
|
||||
HParser *T = h_choice(h_sequence(h_ch('('), E, h_ch(')'), NULL), n, NULL);
|
||||
HParser *E_ = h_choice(h_sequence(E, h_ch('-'), T, NULL), T, NULL);
|
||||
h_bind_indirect(E, E_);
|
||||
HParser *p = h_sequence(E, NULL);
|
||||
|
|
@ -1035,7 +1062,7 @@ int test_lalr(void)
|
|||
h_pprint_lrtable(stdout, g, (HLRTable *)p->backend_data, 0);
|
||||
|
||||
printf("\n==== P A R S E R E S U L T ====\n");
|
||||
HParseResult *res = h_parse(p, (uint8_t *)"syya", 4);
|
||||
HParseResult *res = h_parse(p, (uint8_t *)"n-(n-((n)))-n", 11);
|
||||
if(res)
|
||||
h_pprint(stdout, res->ast, 0, 2);
|
||||
else
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue