From 168760b10a6234259cd80b1c455fbf95d76d10ba Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Wed, 19 Jun 2013 14:16:34 +0200
Subject: [PATCH] return running state from h_lrengine_step
---
src/backends/lr.c | 25 ++++++++++---------------
src/backends/lr.h | 3 +--
2 files changed, 11 insertions(+), 17 deletions(-)
diff --git a/src/backends/lr.c b/src/backends/lr.c
index 0ad45693..2d329b13 100644
--- a/src/backends/lr.c
+++ b/src/backends/lr.c
@@ -183,7 +183,6 @@ HLREngine *h_lrengine_new(HArena *arena, HArena *tarena, const HLRTable *table)
engine->left = h_slist_new(tarena);
engine->right = h_slist_new(tarena);
engine->state = 0;
- engine->running = 1;
engine->arena = arena;
engine->tarena = tarena;
@@ -228,7 +227,8 @@ const HLRAction *h_lrengine_action(HLREngine *engine, HInputStream *stream)
return action;
}
-void h_lrengine_step(HLREngine *engine, const HLRAction *action)
+// run LR parser for one round; returns false when finished
+bool h_lrengine_step(HLREngine *engine, const HLRAction *action)
{
// short-hand names
HSlist *left = engine->left;
@@ -236,11 +236,8 @@ void h_lrengine_step(HLREngine *engine, const HLRAction *action)
HArena *arena = engine->arena;
HArena *tarena = engine->tarena;
- if(action == NULL) {
- // no handle recognizable in input, terminate
- engine->running = false;
- return;
- }
+ if(action == NULL)
+ return false; // no handle recognizable in input, terminate
if(action->type == HLR_SHIFT) {
h_slist_push(left, (void *)(uintptr_t)engine->state);
@@ -280,11 +277,8 @@ void h_lrengine_step(HLREngine *engine, const HLRAction *action)
value = (HParsedToken *)symbol->reshape(make_result(arena, value));
// call validation and semantic action, if present
- if(symbol->pred && !symbol->pred(make_result(tarena, value))) {
- // validation failed -> no parse; terminate
- engine->running = false;
- return;
- }
+ if(symbol->pred && !symbol->pred(make_result(tarena, value)))
+ return false; // validation failed -> no parse; terminate
if(symbol->action)
value = (HParsedToken *)symbol->action(make_result(arena, value));
@@ -292,6 +286,8 @@ void h_lrengine_step(HLREngine *engine, const HLRAction *action)
h_slist_push(right, value);
h_slist_push(right, symbol);
}
+
+ return true;
}
HParseResult *h_lrengine_result(HLREngine *engine)
@@ -317,9 +313,8 @@ HParseResult *h_lr_parse(HAllocator* mm__, const HParser* parser, HInputStream*
HArena *tarena = h_new_arena(mm__, 0); // tmp, deleted after parse
HLREngine *engine = h_lrengine_new(arena, tarena, table);
- // run while the recognizer finds handles in the input
- while(engine->running)
- h_lrengine_step(engine, h_lrengine_action(engine, stream));
+ // iterate engine to completion
+ while(h_lrengine_step(engine, h_lrengine_action(engine, stream)));
HParseResult *result = h_lrengine_result(engine);
if(!result)
diff --git a/src/backends/lr.h b/src/backends/lr.h
index 93122373..b95c1332 100644
--- a/src/backends/lr.h
+++ b/src/backends/lr.h
@@ -69,7 +69,6 @@ typedef struct HLREngine_ {
HSlist *right; // right stack; input appears here
size_t state;
- bool running;
HArena *arena; // will hold the results
HArena *tarena; // tmp, deleted after parse
} HLREngine;
@@ -122,7 +121,7 @@ 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(HLREngine *engine, HInputStream *stream);
-void h_lrengine_step(HLREngine *engine, const HLRAction *action);
+bool h_lrengine_step(HLREngine *engine, const HLRAction *action);
HParseResult *h_lrengine_result(HLREngine *engine);
HParseResult *h_lr_parse(HAllocator* mm__, const HParser* parser, HInputStream* stream);
--
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