From 572f1c8f9e14e521317c54045ee22639d65b5ffe Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Wed, 19 Jun 2013 18:22:19 +0200
Subject: [PATCH] expand stub GLR backend
---
src/backends/glr.c | 60 +++++++++++++++++++++++++++++++++++-----------
1 file changed, 46 insertions(+), 14 deletions(-)
diff --git a/src/backends/glr.c b/src/backends/glr.c
index c57ffd6..429d06b 100644
--- a/src/backends/glr.c
+++ b/src/backends/glr.c
@@ -1,6 +1,25 @@
#include "lr.h"
+/* GLR compilation (LALR w/o failing on conflict) */
+
+int h_glr_compile(HAllocator* mm__, HParser* parser, const void* params)
+{
+ int result = h_lalr_compile(mm__, parser, params);
+
+ if(result == -1 && parser->backend_data) {
+ // table is there, just has conflicts? nevermind, that's okay.
+ result = 0;
+ }
+
+ return result;
+}
+
+void h_glr_free(HParser *parser)
+{
+ h_lalr_free(parser);
+}
+
/* GLR driver */
@@ -12,12 +31,28 @@ HParseResult *h_glr_parse(HAllocator* mm__, const HParser* parser, HInputStream*
HArena *arena = h_new_arena(mm__, 0); // will hold the results
HArena *tarena = h_new_arena(mm__, 0); // tmp, deleted after parse
- HLREngine *engine = h_lrengine_new(arena, tarena, table);
- // iterate engine to completion
- while(h_lrengine_step(engine, h_lrengine_action(engine, stream)));
+ HSlist *engines = h_slist_new(tarena);
+ h_slist_push(engines, h_lrengine_new(arena, tarena, table));
+
+ HParseResult *result = NULL;
+ while(result == NULL && !h_slist_empty(engines)) {
+ for(HSlistNode **x = &engines->head; *x; ) {
+ HLREngine *engine = (*x)->elem;
+
+ const HLRAction *action = h_lrengine_action(engine, stream);
+ // XXX handle conflicts -> fork engine
+ bool running = h_lrengine_step(engine, action);
+
+ if(running) {
+ x = &(*x)->next; // go to next
+ } else {
+ *x = (*x)->next; // remove from list
+ result = h_lrengine_result(engine);
+ }
+ }
+ }
- HParseResult *result = h_lrengine_result(engine);
if(!result)
h_delete_arena(arena);
h_delete_arena(tarena);
@@ -27,9 +62,9 @@ HParseResult *h_glr_parse(HAllocator* mm__, const HParser* parser, HInputStream*
HParserBackendVTable h__glr_backend_vtable = {
- .compile = h_lalr_compile,
+ .compile = h_glr_compile,
.parse = h_glr_parse,
- .free = h_lalr_free
+ .free = h_glr_free
};
@@ -39,16 +74,13 @@ HParserBackendVTable h__glr_backend_vtable = {
int test_glr(void)
{
/*
- E -> E '-' T
- | T
- T -> '(' E ')'
- | 'n' -- also try [0-9] for the charset paths
+ E -> E '+' E
+ | 'd'
*/
- HParser *n = h_ch('n');
+ HParser *d = h_ch('d');
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);
+ HParser *E_ = h_choice(h_sequence(E, h_ch('+'), E, NULL), d, NULL);
h_bind_indirect(E, E_);
HParser *p = E;
@@ -83,7 +115,7 @@ int test_glr(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 *)"d+d+d", 5);
if(res)
h_pprint(stdout, res->ast, 0, 2);
else
--
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