From 5a57adabab0744474d4cd46f2cfe88d5c729ffc4 Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Sat, 15 Jun 2013 20:30:57 +0200
Subject: [PATCH] some refactoring trying to get h_many to work
---
src/backends/lalr.c | 46 ++++++++++++++++++++++-----------------------
src/cfgrammar.c | 6 ++++++
src/cfgrammar.h | 1 +
3 files changed, 29 insertions(+), 24 deletions(-)
diff --git a/src/backends/lalr.c b/src/backends/lalr.c
index 54f6dc8e..0dd1d070 100644
--- a/src/backends/lalr.c
+++ b/src/backends/lalr.c
@@ -207,16 +207,14 @@ static HLRItem *advance_mark(HArena *arena, const HLRItem *item)
return ret;
}
-static HHashSet *closure(HCFGrammar *g, const HHashSet *items)
+static void expand_to_closure(HCFGrammar *g, HHashSet *items)
{
HAllocator *mm__ = g->mm__;
HArena *arena = g->arena;
- HHashSet *ret = h_lrstate_new(arena);
HSlist *work = h_slist_new(arena);
// initialize work list with items
H_FOREACH_KEY(items, HLRItem *item)
- h_hashset_put(ret, item);
h_slist_push(work, (void *)item);
H_END_FOREACH
@@ -231,22 +229,22 @@ static HHashSet *closure(HCFGrammar *g, const HHashSet *items)
if(sym->type == HCF_CHOICE) {
for(HCFSequence **p=sym->seq; *p; p++) {
HLRItem *it = h_lritem_new(arena, sym, (*p)->items, 0);
- if(!h_hashset_present(ret, it)) {
- h_hashset_put(ret, it);
+ if(!h_hashset_present(items, it)) {
+ h_hashset_put(items, it);
h_slist_push(work, it);
}
}
} else { // HCF_CHARSET
for(unsigned int i=0; i<256; i++) {
if(charset_isset(sym->charset, i)) {
- // XXX allocatethese single-character symbols statically somewhere
+ // XXX allocate these single-character symbols statically somewhere
HCFChoice **rhs = h_new(HCFChoice *, 2);
rhs[0] = h_new(HCFChoice, 1);
rhs[0]->type = HCF_CHAR;
rhs[0]->chr = i;
rhs[1] = NULL;
HLRItem *it = h_lritem_new(arena, sym, rhs, 0);
- h_hashset_put(ret, it);
+ h_hashset_put(items, it);
// single-character item needs no further work
}
}
@@ -254,17 +252,8 @@ static HHashSet *closure(HCFGrammar *g, const HHashSet *items)
// this seems as good a place as any to set it
sym->reshape = h_act_first;
}
-
- // if sym derives epsilon, also advance over it
- if(h_derives_epsilon(g, sym)) {
- HLRItem *it = advance_mark(arena, item);
- h_hashset_put(ret, it);
- h_slist_push(work, it);
- }
}
}
-
- return ret;
}
HLRDFA *h_lr0_dfa(HCFGrammar *g)
@@ -287,15 +276,16 @@ HLRDFA *h_lr0_dfa(HCFGrammar *g)
assert(g->start->type == HCF_CHOICE);
for(HCFSequence **p=g->start->seq; *p; p++)
h_hashset_put(start, h_lritem_new(arena, g->start, (*p)->items, 0));
+ expand_to_closure(g, start);
h_hashtable_put(states, start, 0);
h_slist_push(work, start);
h_slist_push(work, 0);
// while work to do (on some state)
- // compute closure
// determine edge symbols
// for each edge symbol:
// advance respective items -> destination state (kernel)
+ // compute closure
// if destination is a new state:
// add it to state set
// add transition to it
@@ -308,8 +298,8 @@ HLRDFA *h_lr0_dfa(HCFGrammar *g)
// maps edge symbols to neighbor states (item sets) of s
HHashTable *neighbors = h_hashtable_new(arena, eq_symbol, hash_symbol);
- // iterate over closure and generate neighboring sets
- H_FOREACH_KEY(closure(g, state), HLRItem *item)
+ // iterate over state (closure) and generate neighboring sets
+ H_FOREACH_KEY(state, HLRItem *item)
HCFChoice *sym = item->rhs[item->mark]; // symbol after mark
if(sym != NULL) { // mark was not at the end
@@ -325,8 +315,10 @@ HLRDFA *h_lr0_dfa(HCFGrammar *g)
}
H_END_FOREACH
- // merge neighbor sets into the set of existing states
+ // merge expanded neighbor sets into the set of existing states
H_FOREACH(neighbors, HCFChoice *symbol, HLRState *neighbor)
+ expand_to_closure(g, neighbor);
+
// look up existing state, allocate new if not found
size_t neighbor_idx;
if(!h_hashset_present(states, neighbor)) {
@@ -528,8 +520,9 @@ static HLREnhGrammar *enhance_grammar(const HCFGrammar *g, const HLRDFA *dfa,
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_symbol, hash_symbol);
+ eg->smap = h_hashtable_new(arena, h_eq_ptr, h_hash_ptr);
eg->corr = h_hashtable_new(arena, eq_symbol, hash_symbol);
+ // XXX must use h_eq/hash_ptr for symbols! so enhanced CHARs are different
eg->arena = arena;
// establish mapping between transitions and symbols
@@ -663,6 +656,8 @@ int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
// contribution to the lookahead
const HStringMap *fs = h_follow(1, eg->grammar, lhs);
assert(fs != NULL);
+ assert(fs->epsilon_branch == NULL);
+ assert(!h_stringmap_empty(fs));
// for each lookahead symbol, put action into table cell
if(fs->end_branch) {
@@ -734,6 +729,7 @@ HParseResult *h_lr_parse(HAllocator* mm__, const HParser* parser, HInputStream*
while(1) {
// make sure there is input on the right stack
if(h_slist_empty(right)) {
+ // XXX use statically-allocated terminal symbols
HCFChoice *x = h_arena_malloc(tarena, sizeof(HCFChoice));
HParsedToken *v;
@@ -841,7 +837,7 @@ void h_pprint_lritem(FILE *f, const HCFGrammar *g, const HLRItem *item)
HCFChoice **x = item->rhs;
HCFChoice **mark = item->rhs + item->mark;
if(*x == NULL) {
- fputs("\"\"", f);
+ fputc('.', f);
} else {
while(*x) {
if(x == mark)
@@ -986,12 +982,14 @@ int test_lalr(void)
| 'n' -- also try [0-9] for the charset paths
*/
+#if 0
HParser *n = h_ch('n');
HParser *E = h_indirect();
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);
+#endif
+ HParser *p = h_choice(h_many(h_ch('x')), h_ch('n'), NULL); //h_sequence(E, NULL);
printf("\n==== G R A M M A R ====\n");
HCFGrammar *g = h_cfgrammar(&system_allocator, p);
@@ -1024,7 +1022,7 @@ 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 *)"n-(n-((n)))-n", 13);
+ HParseResult *res = h_parse(p, (uint8_t *)"xxn-(n-((n)))-n", 13);
if(res)
h_pprint(stdout, res->ast, 0, 2);
else
diff --git a/src/cfgrammar.c b/src/cfgrammar.c
index a874236d..199ef5f1 100644
--- a/src/cfgrammar.c
+++ b/src/cfgrammar.c
@@ -331,6 +331,12 @@ bool h_stringmap_present_epsilon(const HStringMap *m)
return (m->epsilon_branch != NULL);
}
+bool h_stringmap_empty(const HStringMap *m)
+{
+ return (m->epsilon_branch == NULL
+ && m->end_branch == NULL
+ && h_hashtable_empty(m->char_branches));
+}
const HStringMap *h_first(size_t k, HCFGrammar *g, const HCFChoice *x)
{
diff --git a/src/cfgrammar.h b/src/cfgrammar.h
index c70c68a3..57f6f68b 100644
--- a/src/cfgrammar.h
+++ b/src/cfgrammar.h
@@ -49,6 +49,7 @@ void h_stringmap_replace(HStringMap *m, void *old, void *new);
void *h_stringmap_get(const HStringMap *m, const uint8_t *str, size_t n, bool end);
bool h_stringmap_present(const HStringMap *m, const uint8_t *str, size_t n, bool end);
bool h_stringmap_present_epsilon(const HStringMap *m);
+bool h_stringmap_empty(const HStringMap *m);
static inline HStringMap *h_stringmap_get_char(const HStringMap *m, const uint8_t c)
{ return h_hashtable_get(m->char_branches, (void *)char_key(c)); }
--
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