From 995f138c293a3db430ced10c688d07f0acf8baa8 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Sat, 30 Oct 2021 11:33:15 +0200
Subject: Prepare for scope check

---
 src/parser.c | 57 +++++++++++++++++++++++++++++++++++++++++++++------------
 src/parser.h |  5 +++--
 2 files changed, 48 insertions(+), 14 deletions(-)

(limited to 'src')

diff --git a/src/parser.c b/src/parser.c
index e16fc4a..2429f68 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -3,7 +3,13 @@
 
 static Object **objects = NULL;
 static Root *roots = NULL;
+static Environment **environments = NULL;
 
+static char *builtins [] = {
+    "+", "-", "*", "/", "%",
+    "=", "<", ">", "<=", ">=",
+    "not", "and", "or",
+};
 
 uint64_t
 symbol_hash(const HashTable *table, void *key) {
@@ -382,9 +388,16 @@ parse_tree(Parser *parser, Errors *errors) {
     return NULL;
 }
 
+void
+scope_check(Environment *env) {
+    // STUB
+}
+
 Root *
 parse(Token *tokens, Errors *errors) {
     array_init(roots, 0);
+    array_init(objects, 0);
+    array_init(environments, 0);
     Parser parser = {
         .tokens = tokens,
         .current = 0,
@@ -400,27 +413,39 @@ parse(Token *tokens, Errors *errors) {
         array_push(roots, root);
     }
 
-    // TEST INSERTION/LOOKUP.
-    HashTable *table = ht_init(symbol_hash, object_equal);
-    ht_insert(table, &roots[0][0], &roots[1][0]);
-    ht_insert(table, &roots[2][0], &roots[3][0]);
-    Object *val = ht_lookup(table, &roots[2][0]);
-    object_display(val);
-    val = ht_lookup(table, &roots[0][0]);
-    object_display(val);
-    ht_free(table);
+    // Prepare global environment of builtin functions.
+    Environment *global_env = env_alloc(NULL);
+    size_t n_builtins = sizeof(builtins) / sizeof(char*);
+    for (size_t i = 0; i < n_builtins; i++) {
+        // Prepare builtin symbol.
+        char *str = builtins[i];
+        size_t str_n = strlen(str);
+        Object *symbol = object_alloc((Token){0}, OBJ_TYPE_SYMBOL);
+        array_init(symbol->text, str_n);
+        array_insert(symbol->text, str, str_n);
+
+        // Insert in global table.
+        ht_insert(global_env->table, symbol, symbol);
+    }
 
     // Perform semantic analysis.
+    scope_check(global_env);
     // TODO: Check that symbols are defined before usage.
     // TODO: Remove unnecessary statements.
     return roots;
 }
 
+Environment *
+env_alloc(Environment *parent) {
+    Environment *env = malloc(sizeof(Environment));
+    env->table = ht_init(symbol_hash, (EqFunc*)object_equal);
+    env->parent = parent;
+    array_push(environments, env);
+    return env;
+}
+
 Object *
 object_alloc(Token tok, ObjectType type) {
-    if (objects == NULL) {
-        array_init(objects, 0);
-    }
     Object *node = malloc(sizeof(Object));
     node->line = tok.line;
     node->col = tok.col;
@@ -452,6 +477,14 @@ free_objects(void) {
         }
         array_free(objects);
     }
+    if (environments != NULL) {
+        for (size_t i = 0; i < array_size(environments); i++) {
+            Environment *env = environments[i];
+            ht_free(env->table);
+            free(env);
+        }
+        array_free(environments);
+    }
     array_free(roots);
 }
 
diff --git a/src/parser.h b/src/parser.h
index d1eddc7..dff40d8 100755
--- a/src/parser.h
+++ b/src/parser.h
@@ -62,7 +62,7 @@ typedef struct Object {
 typedef struct Environment {
     HashTable *table;
     struct Environment *parent;
-};
+} Environment;
 
 typedef struct Parser {
     Token *tokens;
@@ -71,7 +71,7 @@ typedef struct Parser {
 
 typedef Object* Root;
 
-// Mimics the functionality in the Scanner functions, but for tokens.
+// Token scanner.
 Token next_token(Parser *parser);
 Token previous_token(Parser *parser);
 Token rewind_token(Parser *parser);
@@ -95,6 +95,7 @@ void object_display(Object *obj);
 bool object_equal(Object *a, Object *b);
 
 // Manage resources.
+Environment * env_alloc(Environment *parent);
 Object * object_alloc(Token tok, ObjectType type);
 void object_free(Object *node);
 void free_objects(void);
-- 
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