From 4b5a93666723380e26e58ea23fad5c244b6ee66a Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Wed, 12 Jun 2013 16:38:50 +0200
Subject: [PATCH] handle charsets
---
src/backends/lalr.c | 38 +++++++++++++++++++++++++++-----------
1 file changed, 27 insertions(+), 11 deletions(-)
diff --git a/src/backends/lalr.c b/src/backends/lalr.c
index 8178f2d2..66fe42c7 100644
--- a/src/backends/lalr.c
+++ b/src/backends/lalr.c
@@ -229,15 +229,33 @@ static HHashSet *closure(HCFGrammar *g, const HHashSet *items)
HCFChoice *sym = item->rhs[item->mark]; // symbol after mark
// if there is a non-terminal after the mark, follow it
- // XXX: do we have to count HCF_CHARSET as nonterminal?
- if(sym != NULL && sym->type == HCF_CHOICE) {
+ // NB: unlike LLk, we do consider HCF_CHARSET a non-terminal here
+ if(sym != NULL && (sym->type==HCF_CHOICE || sym->type==HCF_CHARSET)) {
// add items corresponding to the productions of sym
- 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);
- h_slist_push(work, it);
+ 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);
+ h_slist_push(work, it);
+ }
+ }
+ } else { // HCF_CHARSET
+ for(unsigned int i=0; i<256; i++) {
+ if(charset_isset(sym->charset, i)) {
+ HCFChoice **rhs = h_arena_malloc(arena, 2 * sizeof(HCFChoice *));
+ rhs[0] = h_arena_malloc(arena, sizeof(HCFChoice));
+ 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);
+ // single-character item needs no further work
+ }
}
+ // if sym is a non-terminal, we need a reshape on it
+ // this seems as good a place as any to set it
+ sym->reshape = h_act_first;
}
// if sym derives epsilon, also advance over it
@@ -615,8 +633,6 @@ h_lr_lookup(const HLRTable *table, size_t state, const HCFChoice *symbol)
}
}
-// XXX also, what about charsets!?
-
HParseResult *h_lr_parse(HAllocator* mm__, const HParser* parser, HInputStream* stream)
{
HLRTable *table = parser->backend_data;
@@ -884,7 +900,7 @@ int test_lalr(void)
*/
// XXX make LALR example
- HParser *X = h_optional(h_ch('x'));
+ HParser *X = h_optional(h_in((uint8_t *)"rst", 3));
HParser *Y = h_sequence(h_ch('y'), h_ch('y'), NULL);
HParser *A = h_sequence(X, Y, h_ch('a'), NULL);
HParser *B = h_sequence(Y, h_ch('b'), NULL);
@@ -921,7 +937,7 @@ 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 *)"xyya", 4);
+ HParseResult *res = h_parse(p, (uint8_t *)"syya", 4);
if(res)
h_pprint(stdout, res->ast, 0, 2);
else
--
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