#include <grammar.h>
+#include <first.h>
+#include <item.h>
#ifdef DEBUG
#include <stdio.h>
#endif
-typedef struct
-{
- symbol_t* left;
- rule_t* right;
- GList* dot;
-} item_t;
-
-item_t* item_new (symbol_t* left, rule_t* right)
+item_t* item_new (symbol_t* left, rule_t* right, symbol_t* lookahead)
{
item_t* item;
item = g_malloc (sizeof (item_t));
item->left = left;
item->right = right;
item->dot = grammar_get_rule (right);
+ item->lookahead = lookahead;
return item;
}
{
item_t* newitem;
int n;
- newitem = item_new (symbol_copy (item->left), rule_copy (item->right));
+ newitem = item_new (symbol_copy (item->left), rule_copy (item->right),
+ symbol_copy (item->lookahead));
n = g_list_position (grammar_get_rule (item->right), item->dot);
newitem->dot = g_list_nth (grammar_get_rule (newitem->right), n);
return newitem;
return c;
if ((c = rule_cmp (a->right, b->right)) != 0)
return c;
+ if ((c = symbol_cmp (a->lookahead, b->lookahead)) != 0)
+ return c;
na = g_list_position (grammar_get_rule (a->right), a->dot);
nb = g_list_position (grammar_get_rule (b->right), b->dot);
if (na < nb)
guint hash;
item = (item_t*) data;
hash = rule_hash (item->right) * 37 + symbol_hash (item->left);
+ hash = hash * 37 + symbol_hash (item->lookahead);
return hash;
}
{
g_free (item->left);
rule_delete (item->right);
+ g_free (item->lookahead);
g_free (item);
}
{
fprintf (stdout, ".");
}
- fprintf (stdout, "\n");
+ fprintf (stdout, ", %s\n", g_quark_to_string (item->lookahead->value));
}
#endif
}
#endif
+rule_t* rule_new_item (item_t* item)
+{
+
+ rule_t* rule;
+ GList* l;
+ rule = rule_new ();
+ l = g_list_next (item->dot);
+ while (l != NULL)
+ {
+ rule_append (rule, symbol_copy (l->data));
+ l = g_list_next (l);
+ }
+ rule_append (rule, symbol_copy (item->lookahead));
+ return rule;
+
+}
+
void item_set_closure_step (GHashTable* item_set, grammar_t* grammar,
- item_t* item)
+ GHashTable* first, item_t* item)
{
if (item->dot != NULL)
{
if (symbol->terminal == FALSE)
{
GList* rules;
+ GList* terminals;
+ rule_t* rule;
+ rule = rule_new_item (item);
+ terminals = first_rule (first, rule);
+ rule_delete (rule);
rules = grammar_get_rules (grammar, symbol);
while (rules != NULL)
{
- rule_t* rule;
- item_t* newitem;
- rule = rule_copy (rules->data);
- newitem = item_new (symbol_copy (symbol), rule);
- if (!item_set_add (item_set, newitem))
- item_delete (newitem);
+ GList* lookahead;
+ lookahead = terminals;
+ while (lookahead != NULL)
+ {
+ rule_t* rule;
+ item_t* newitem;
+ rule = rule_copy (rules->data);
+ newitem = item_new (symbol_copy (symbol), rule,
+ symbol_copy (lookahead->data));
+ if (!item_set_add (item_set, newitem))
+ item_delete (newitem);
+ lookahead = g_list_next (lookahead);
+ }
rules = g_list_next (rules);
}
+ g_list_free (terminals);
}
}
}
-GHashTable* item_set_closure (GHashTable* item_set, grammar_t* grammar)
+GHashTable* item_set_closure (GHashTable* item_set, grammar_t* grammar,
+ GHashTable* first)
{
int size;
int last_size;
g_hash_table_foreach (item_set, put_key_on_list, &l);
while (l != NULL)
{
- item_set_closure_step (item_set, grammar, l->data);
+ item_set_closure_step (item_set, grammar, first, l->data);
l = g_list_next (l);
}
g_list_free (l);
}
GHashTable* item_set_goto (GHashTable* item_set, grammar_t* grammar,
- symbol_t* symbol)
+ GHashTable* first, symbol_t* symbol)
{
GList* l;
GHashTable* newitem_set;
}
l = g_list_next (l);
}
- return item_set_closure (newitem_set, grammar);
+ return item_set_closure (newitem_set, grammar, first);
}
#endif
GHashTable* item_collection_goto (GHashTable* collection, grammar_t* grammar,
- GHashTable* item_set, symbol_t* symbol)
+ GHashTable* first, GHashTable* item_set,
+ symbol_t* symbol)
{
GHashTable* symbols;
GHashTable* newitem_set;
{
return NULL;
}
- goto_item_set = item_set_goto (item_set, grammar, symbol);
+ goto_item_set = item_set_goto (item_set, grammar, first, symbol);
if (!item_collection_add (collection, goto_item_set, &old_item_set))
{
g_hash_table_insert (symbols, symbol, old_item_set);
}
}
-void item_set_collection (grammar_t* grammar, symbol_t* start)
+GHashTable* item_set_collection (grammar_t* grammar, GHashTable* first,
+ symbol_t* start)
{
GHashTable* collection;
GHashTable* item_set;
GList* new_item_sets;
rule = rule_new ();
rule_append (rule, symbol_copy (start));
- item = item_new (symbol_new (FALSE, -1), rule);
+ item = item_new (symbol_new (FALSE, -1), rule, symbol_new (TRUE, 0));
item_set = item_set_new ();
item_set_add (item_set, item);
- item_set_closure (item_set, grammar);
+ item_set_closure (item_set, grammar, first);
collection = g_hash_table_new_full (item_set_hash, item_set_equal,
g_hash_table_destroy, NULL);
item_collection_add (collection, item_set, NULL);
{
symbol = (symbol_t*) item->dot->data;
if ((new_item_set =
- item_collection_goto (collection, grammar,
+ item_collection_goto (collection, grammar, first,
next_item_set, symbol)) != NULL)
{
g_list_append (new_item_sets, new_item_set);
#ifdef DEBUG
item_collection_print (collection);
#endif
- g_hash_table_destroy (collection);
+ return collection;
}
--- /dev/null
+#ifndef ITEM_H
+#define ITEM_H
+
+typedef struct
+{
+ symbol_t* left;
+ rule_t* right;
+ GList* dot;
+ symbol_t* lookahead;
+} item_t;
+
+GHashTable* item_set_collection (Grammar*, GHashTable*, symbol_t*);
+
+#endif
--- /dev/null
+#include <grammar.h>
+#include <stdlib.h>
+
+enum { PARSER_SHIFT, PARSER_REDUCE, PARSER_ACCEPT };
+
+struct _transition_t
+{
+ gint action;
+ gint state;
+ symbol_t* left;
+ rule_t* right;
+};
+
+struct _lr1_t
+{
+ nextcb cb;
+ gpointer data;
+ GHashTable* table;
+ GList* stack;
+};
+
+typedef struct
+{
+ gint state;
+ gpointer attrib;
+} state_t;
+
+transition_t* transition_shift_new (gint state)
+{
+ transition_t* transition;
+ transition = g_malloc (sizeof (transition_t));
+ transition->action = PARSER_SHIFT;
+ transition->state = state;
+ transition->left = NULL;
+ transition->right = NULL;
+ return transition;
+}
+
+transition_t* transition_reduce_new (symbol_t* left, rule_t* right)
+{
+ transition_t* transition;
+ transition = g_malloc (sizeof (transition_t));
+ transition->action = PARSER_REDUCE;
+ transition->state = 0;
+ transition->left = left;
+ transition->right = right;
+ return transition;
+}
+
+transition_t* transition_accept_new ()
+{
+ transition_t* transition;
+ transition = g_malloc (sizeof (transition_t));
+ transition->action = PARSER_ACCEPT;
+ transition->state = 0;
+ transition->left = NULL;
+ transition->right = NULL;
+ return transition;
+}
+
+void transition_delete (transition_t* transition)
+{
+ if (transition->left != NULL)
+ g_free (transition->left);
+ if (transition->right != NULL)
+ rule_delete (transition->right);
+ g_free (transition);
+}
+
+void lr1_push (lr1_t* parser, gint st, gpointer attrib)
+{
+ state_t* state;
+ state = g_malloc (sizeof (state_t));
+ state->state = st;
+ state->attrib = attrib;
+ parser->stack = g_list_prepend (parser->stack, state);
+}
+
+static gboolean lr1_pop (lr1_t* parser, gpointer* attrib)
+{
+
+ GList* l;
+ state_t* state;
+ if ((l = g_list_first (parser->stack)) == NULL)
+ return FALSE;
+ parser->stack = g_list_remove_link (l, l);
+ state = (state_t*) l->data;
+ if (attrib)
+ *attrib = state->attrib;
+ g_free (state);
+ g_list_free (l);
+ return TRUE;
+
+}
+
+lr1_t* lr1_new (nextcb cb, gpointer data)
+{
+
+ lr1_t* parser;
+
+ parser = g_malloc (sizeof (lr1_t));
+ parser->cb = cb;
+ parser->data = data;
+
+ parser->stack = NULL;
+ parser->table = g_hash_table_new_full (g_direct_hash, g_direct_equal,
+ NULL, g_hash_table_destroy);
+
+ return parser;
+
+}
+
+void lr1_delete (lr1_t* parser)
+{
+
+ GList* l;
+
+ for (l = g_list_first (parser->stack); l != NULL; l = g_list_next (l))
+ {
+ g_free (l->data);
+ }
+
+ g_list_free (parser->stack);
+
+ g_hash_table_destroy (parser->table);
+
+ g_free (parser);
+
+}
+
+gboolean lr1_add (lr1_t* parser, gint state, symbol_t* symbol,
+ transition_t* transition)
+{
+
+ GHashTable* table;
+
+ if (!g_hash_table_lookup_extended (parser->table, GINT_TO_POINTER(state),
+ NULL, (gpointer*) &table))
+ {
+ table = g_hash_table_new_full (symbol_hash, symbol_equal,
+ g_free, transition_delete);
+ g_hash_table_insert (parser->table, GINT_TO_POINTER(state), table);
+ }
+
+ if (g_hash_table_lookup_extended (table, symbol, NULL, NULL))
+ {
+ return FALSE;
+ }
+
+ g_hash_table_insert (table, symbol, transition);
+ return TRUE;
+
+}
+
+gboolean lr1_lookup (lr1_t* parser, gint state, symbol_t* symbol,
+ transition_t** transition)
+{
+
+ GHashTable* table;
+ transition_t* trans;
+
+ if (!g_hash_table_lookup_extended (parser->table, GINT_TO_POINTER(state),
+ NULL, (gpointer*) &table))
+ {
+ return FALSE;
+ }
+
+ if (!g_hash_table_lookup_extended (table, symbol,
+ NULL, (gpointer*) &trans))
+ {
+ return FALSE;
+ }
+
+ if (transition)
+ *transition = trans;
+
+ return TRUE;
+
+}
+
+static gpointer leaf_new (gpointer data)
+{
+ return g_node_new (data);
+}
+
+static gpointer tree_new (rule_t* rule)
+{
+ return g_node_new (rule);
+}
+
+static gpointer tree_add (gpointer tree, gpointer data)
+{
+ return g_node_prepend (tree, data);
+}
+
+gpointer lr1_build (lr1_t* parser)
+{
+
+ state_t* state;
+ symbol_t* symbol;
+ transition_t* transition;
+ gpointer attrib;
+ GList* l;
+
+ symbol = g_malloc (sizeof (symbol_t));
+
+ symbol->value = parser->cb (parser->data, &attrib);
+ symbol->terminal = TRUE;
+
+ while (1)
+ {
+
+ l = g_list_first (parser->stack);
+ state = (state_t*) l->data;
+ if (!lr1_lookup (parser, state->state, symbol, &transition))
+ return NULL;
+
+ if (transition->action == PARSER_SHIFT)
+ {
+ gint st;
+ lr1_push (parser, transition->state, leaf_new (attrib));
+ symbol->value = parser->cb (parser->data, &attrib);
+ symbol->terminal = TRUE;
+ }
+
+ else if (transition->action == PARSER_REDUCE)
+ {
+
+ state_t* state;
+ transition_t* trans;
+ GList* l;
+ gpointer attrib;
+
+ attrib = tree_new (symbol_copy (transition->left));
+
+ for (l = grammar_get_rule (transition->right);
+ l != NULL;
+ l = g_list_previous (l))
+ {
+ gpointer attr;
+ if (!lr1_pop (parser, &attr))
+ return NULL;
+ tree_add (attrib, attr);
+ }
+
+ l = g_list_first (parser->stack);
+ state = (state_t*) l->data;
+ lr1_lookup (parser, state->state, transition->left, &trans);
+ lr1_push (parser, trans->state, attrib);
+
+ }
+
+ else if (transition->action == PARSER_ACCEPT)
+ {
+ l = g_list_first (parser->stack);
+ state = (state_t*) l->data;
+ return state->attrib;
+ }
+
+ }
+
+ return NULL;
+
+}
--- /dev/null
+#ifndef LR1_H
+#define LR1_H
+
+#include <grammar.h>
+
+typedef struct _transition_t transition_t;
+typedef struct _lr1_t lr1_t;
+
+transition_t* transition_shift_new (gint);
+transition_t* transition_reduce_new (symbol_t*, rule_t*);
+transition_t* transition_accept_new ();
+void transition_delete (transition_t*);
+lr1_t* lr1_new (nextcb, gpointer);
+void lr1_delete (lr1_t*);
+void lr1_add (lr1_t*, gint, symbol_t*, transition_t*);
+void lr1_push (lr1_t*, gint, gpointer);
+gpointer lr1_build (lr1_t*);
+
+#endif
projects / cascardo / grammar.git / commitdiff