Change Environment to store locals in array

This will help directly translate the locals to assembly.

4 files changed, 42 insertions, 25 deletions

diff --git a/src/compiler.h b/src/compiler.h
index d4b9e72..fe36ecf 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -405,6 +405,7 @@ compile_proc_call(Object *obj) {
 
 void
 compile_if(Object *obj) {
+    context_printf("    ;; --> compile_if\n");
     char *lab_false = generate_label("BDLL");
     compile_object(obj->condition);
     context_printf("    pop     rax\n");
@@ -420,6 +421,7 @@ compile_if(Object *obj) {
     } else {
         context_printf("%s:\n", lab_false);
     }
+    context_printf("    ;; <-- compile_if\n");
 }
 
 void
diff --git a/src/main.c b/src/main.c
index cf4bfa4..8962519 100644
--- a/src/main.c
+++ b/src/main.c
@@ -33,7 +33,7 @@ process_source(const StringView *source, const char *file_name) {
     }
 
     // Parser.
-    Root *roots = parse(tokens, &errors);
+    Program program = parse(tokens, &errors);
     if (errors.n != 0) {
         report_errors(&errors, file_name);
         free_objects();
@@ -45,7 +45,7 @@ process_source(const StringView *source, const char *file_name) {
     // TODO: Optimization.
 
     // Compilation.
-    compile(roots);
+    compile(program.roots);
 
     // Free resources.
     free_objects();
diff --git a/src/parser.c b/src/parser.c
index 5632e13..100916b 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -14,14 +14,6 @@ static char *builtins [] = {
     "cons", "car", "cdr",
 };
 
-uint64_t
-symbol_hash(const HashTable *table, void *key) {
-    Object *obj = key;
-    uint64_t hash = _xor_shift_hash(obj->text.start, obj->text.n);
-    hash = _fibonacci_hash(hash, table->shift_amount);
-    return hash;
-}
-
 Token
 peek_token(const Parser *parser) {
     if (parser->current >= array_size(parser->tokens)) {
@@ -436,12 +428,22 @@ parse_tree(Parser *parser, Errors *errors) {
     return NULL;
 }
 
+ssize_t
+find_local_index(Object **locals, Object *symbol) {
+    for (size_t i = 0; i < array_size(locals); i++) {
+        if (object_equal(locals[i], symbol)) {
+            return i;
+        }
+    }
+    return -1;
+}
+
 Object *
 symbol_in_env(Environment *env, Object *symbol) {
     while (env != NULL) {
-        Object *found = ht_lookup(env->table, symbol);
-        if (found != NULL) {
-            return found;
+        ssize_t idx = find_local_index(env->locals, symbol);
+        if (idx != -1) {
+            return env->locals[idx];
         }
         env = env->parent;
     }
@@ -449,6 +451,14 @@ symbol_in_env(Environment *env, Object *symbol) {
 }
 
 void
+insert_local(Environment *env, Object *symbol) {
+    if (find_local_index(env->locals, symbol) != -1) {
+        return;
+    }
+    array_push(env->locals, symbol);
+}
+
+void
 semantic_analysis(Environment *env, Object *obj, Errors *errors) {
     if (obj == NULL || obj->visited) {
         return;
@@ -457,7 +467,7 @@ semantic_analysis(Environment *env, Object *obj, Errors *errors) {
     switch (obj->type) {
         case OBJ_TYPE_SYMBOL: {
             Object *found = symbol_in_env(env, obj);
-            if (symbol_in_env(env, obj) == NULL) {
+            if (found == NULL) {
                 error_push(errors, (Error){
                     .type = ERR_TYPE_PARSER,
                     .value = ERR_SYMBOL_NOT_FOUND,
@@ -469,7 +479,7 @@ semantic_analysis(Environment *env, Object *obj, Errors *errors) {
             semantic_analysis(env, found, errors);
         } break;
         case OBJ_TYPE_DEF: {
-            ht_insert(env->table, obj->var_name, obj->var_expr);
+            insert_local(env, obj->var_name);
             semantic_analysis(env, obj->var_expr, errors);
         } break;
         case OBJ_TYPE_SET: {
@@ -538,7 +548,7 @@ semantic_analysis(Environment *env, Object *obj, Errors *errors) {
     }
 }
 
-Root *
+Program
 parse(Token *tokens, Errors *errors) {
     array_init(roots, 0);
     array_init(objects, 0);
@@ -552,7 +562,7 @@ parse(Token *tokens, Errors *errors) {
     while (has_next_token(&parser)) {
         Object *root = parse_tree(&parser, errors);
         if (errors->n != 0) {
-            return NULL;
+            return (Program){0};
         }
         array_push(roots, root);
     }
@@ -568,7 +578,7 @@ parse(Token *tokens, Errors *errors) {
         symbol->text = (StringView){str, str_n};
 
         // Insert in global table.
-        ht_insert(global_env->table, symbol, symbol);
+        insert_local(global_env, symbol);
     }
 
     // Perform semantic analysis:
@@ -593,7 +603,7 @@ parse(Token *tokens, Errors *errors) {
         semantic_analysis(global_env, root, errors);
         if (errors->n != 0) {
             array_free(final_roots);
-            return NULL;
+            return (Program){0};
         }
     }
     array_free(roots);
@@ -604,13 +614,14 @@ parse(Token *tokens, Errors *errors) {
     // TODO: Type check basic expressions (e.g. arithmetic/numeric comparisons).
     // We can't be sure when we have functions unless the return type is known.
 
-    return roots;
+    return (Program){roots, global_env};
 }
 
 Environment *
 env_alloc(Environment *parent) {
     Environment *env = malloc(sizeof(Environment));
-    env->table = ht_init(symbol_hash, (EqFunc*)object_equal);
+    env->locals = NULL;
+    array_init(env->locals, 0);
     env->parent = parent;
     array_push(environments, env);
     return env;
@@ -650,7 +661,7 @@ free_objects(void) {
     if (environments != NULL) {
         for (size_t i = 0; i < array_size(environments); i++) {
             Environment *env = environments[i];
-            ht_free(env->table);
+            array_free(env->locals);
             free(env);
         }
         array_free(environments);
diff --git a/src/parser.h b/src/parser.h
index 9414a24..c117c61 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -2,10 +2,9 @@
 #define BDL_PARSER_H
 
 #include "lexer.h"
-#include "hashtable.h"
 
 typedef struct Environment {
-    HashTable *table;
+    struct Object **locals;
     struct Environment *parent;
 } Environment;
 
@@ -74,6 +73,11 @@ typedef struct Parser {
 
 typedef Object* Root;
 
+typedef struct Program {
+    Root *roots;
+    Environment *env;
+} Program;
+
 // Token scanner.
 Token next_token(Parser *parser);
 Token previous_token(Parser *parser);
@@ -91,7 +95,7 @@ Object * parse_list(Parser *parser, Errors *errors);
 Object * parse_lambda(Parser *parser, Errors *errors);
 Object * parse_if(Parser *parser, Errors *errors);
 Object * parse_var(Parser *parser, Errors *errors);
-Root * parse(Token *tokens, Errors *errors);
+Program parse(Token *tokens, Errors *errors);
 
 // Object operations.
 void object_display(Object *obj);