From ebcfa8691191d2306546900d1867ef78cebdabf0 Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Wed, 8 May 2013 18:49:05 +0200
Subject: [PATCH] finish (untested) LL(1) table generation
---
src/backends/ll.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 53 insertions(+), 1 deletion(-)
diff --git a/src/backends/ll.c b/src/backends/ll.c
index 8ed4d604..3f1ee5ad 100644
--- a/src/backends/ll.c
+++ b/src/backends/ll.c
@@ -68,12 +68,64 @@ HHashSet *h_predict(HCFGrammar *g, const HCFChoice *A, const HCFSequence *rhs)
}
}
+/* Generate entries for the production "A -> rhs" in the given table row. */
+static
+int fill_table_row(HCFGrammar *g, HHashTable *row,
+ const HCFChoice *A, HCFSequence *rhs)
+{
+ // iterate over predict(A -> rhs)
+ HHashSet *pred = h_predict(g, A, rhs);
+
+ size_t i;
+ HHashTableEntry *hte;
+ for(i=0; i < pred->capacity; i++) {
+ for(hte = &pred->contents[i]; hte; hte = hte->next) {
+ if(hte->key == NULL)
+ continue;
+ HCFToken x = (uintptr_t)hte->key;
+
+ if(h_hashtable_present(row, (void *)x))
+ return -1; // table would be ambiguous
+
+ h_hashtable_put(row, (void *)x, rhs);
+ }
+ }
+
+ return 0;
+}
+
/* Generate the LL parse table from the given grammar.
* Returns -1 on error, 0 on success.
*/
static int fill_table(HCFGrammar *g, HLLTable *table)
{
- return -1; // XXX
+ // iterate over g->nts
+ size_t i;
+ HHashTableEntry *hte;
+ for(i=0; i < g->nts->capacity; i++) {
+ for(hte = &g->nts->contents[i]; hte; hte = hte->next) {
+ if(hte->key == NULL)
+ continue;
+ const HCFChoice *a = hte->key; // production's left-hand symbol
+
+ // create table row for this nonterminal
+ HHashTable *row = h_hashtable_new(table->arena, h_eq_ptr, h_hash_ptr);
+ h_hashtable_put(table->rows, a, row);
+
+ // iterate over a's productions
+ HCFSequence **s;
+ for(s = a->seq; *s; s++) {
+ // record this production in row as appropriate
+ // this can signal an ambiguity conflict.
+ // NB we don't worry about deallocating anything, h_ll_compile will
+ // delete the whole arena for us.
+ if(fill_table_row(g, row, a, *s) < 0)
+ return -1;
+ }
+ }
+ }
+
+ return 0;
}
int h_ll_compile(HAllocator* mm__, HParser* parser, const void* params)
--
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