For loop iterate through arrays and slices

ast.cpp

@@ -163,6 +163,10 @@ struct Ast_For: Ast{
   Ast_Expr *cond;
   Ast_Expr *iter;
   Ast_Scope *scope;
+
+  Ast_Decl *array_traversal_var;
+  bool is_array_traversal;
+  bool is_also_slice_traversal;
 };
 
 struct Ast_Lambda : Ast_Expr {
@@ -266,9 +270,9 @@ struct Ast_Decl: Ast{
   result->pos     = ipos;                                              \
   result->di      = ++pctx->unique_ids
 
-#define MAKE_AST(T,kind,pos,flags) (T *)ast_new(sizeof(T), kind, pos, flags)
+#define new_ast(T,kind,pos,flags) (T *)_new_ast(sizeof(T), kind, pos, flags)
 function Ast *
-ast_new(SizeU size, Ast_Kind kind, Token *pos, Ast_Flag flags = 0){
+_new_ast(SizeU size, Ast_Kind kind, Token *pos, Ast_Flag flags = 0){
   Ast *result = (Ast *)exp_alloc(pctx->perm, size, AF_ZeroMemory);
   result->flags   = flags;
   result->kind    = kind;

ccodegen.cpp

@@ -500,14 +500,41 @@ gen_ast(Ast *ast){
     }
 
     CASE(FOR, For){
-      gen("for(");
-      if(node->init) gen_expr(node->init);
-      gen(";");
-      if(node->cond) gen_expr(node->cond);
-      gen(";");
-      if(node->iter) gen_expr(node->iter);
-      gen(")");
-      gen_stmt_scope(node->scope);
+
+      // Array iter
+      if(node->is_array_traversal){
+        gen("for(S64 _i%d = 0; _i%d < ", node->pos->line, node->pos->line);
+        gen_expr(node->cond);
+        gen(".len; _i%d+=1)", node->pos->line);
+        gen("{");
+        global_indent++;
+        genln("");
+        gen_simple_decl(node->array_traversal_var->type, node->array_traversal_var->name);
+        gen(" = ");
+        gen_expr(node->cond);
+        if(node->is_also_slice_traversal) gen(".data");
+        gen(" + _i%d;", node->pos->line);
+        For(node->scope->stmts) {
+          gen_line(it);
+          genln("");
+          gen_ast(it);
+        }
+        global_indent--;
+        genln("}");
+      }
+
+      // Normal for loop
+      else{
+        gen("for(");
+        if(node->init) gen_expr(node->init);
+        gen(";");
+        if(node->cond) gen_expr(node->cond);
+        gen(";");
+        if(node->iter) gen_expr(node->iter);
+        gen(")");
+        gen_stmt_scope(node->scope);
+      }
+
       BREAK();
     }
 

compiler.h

@@ -175,6 +175,7 @@ Intern_String keyword_enum;
 
 Intern_String intern_void;
 Intern_String intern_foreign;
+Intern_String intern_it;
 Intern_String intern_strict;
 Intern_String intern_flag;
 
@@ -240,6 +241,7 @@ lex_init(Allocator *token_string_arena, Allocator *map_allocator, Lexer *l){
   intern_strict = intern_string(&l->interns, "strict"_s);
   intern_void = intern_string(&l->interns, "void"_s);
   intern_flag = intern_string(&l->interns, "flag"_s);
+  intern_it = intern_string(&l->interns, "it"_s);
 }
 
 function void

parsing.cpp

@@ -234,7 +234,7 @@ parse_stmt_scope(Ast_Scope *scope_defined_outside = 0){
       }
 
       else if(token_match_keyword(keyword_switch)){
-        Ast_Switch *result = MAKE_AST(Ast_Switch, AST_SWITCH, token, AST_STMT);
+        Ast_Switch *result = new_ast(Ast_Switch, AST_SWITCH, token, AST_STMT);
         result->value = parse_expr();
         result->cases = {scratch};
 
@@ -245,7 +245,7 @@ parse_stmt_scope(Ast_Scope *scope_defined_outside = 0){
             continue;
           }
 
-          Ast_Switch_Case *switch_case = MAKE_AST(Ast_Switch_Case, AST_SWITCH_CASE, token_get(), AST_STMT);
+          Ast_Switch_Case *switch_case = new_ast(Ast_Switch_Case, AST_SWITCH_CASE, token_get(), AST_STMT);
           if(token_match_pound(pctx->intern("fallthrough"_s)))
             switch_case->fallthrough = true;
 

programs/any.kl

@@ -1,5 +1,4 @@
 
-
 main :: (argc: int, argv: **char): int
   test_arrays()
   test_any()
@@ -14,6 +13,11 @@ test_arrays :: ()
     assert(i+1 == array1[i])
   array6: []*S64 = {&array1[0]}
 
+  for array1
+    *it = 0
+  for i := 0, i < length_of(array1), i+=1
+    assert(0 == array1[i])
+
 test_any :: ()
   some_int_value := 10
   thing: Any = some_int_value

typechecking.cpp

@@ -566,7 +566,23 @@ resolve_stmt(Ast *ast, Ast_Type *ret){
       }
 
       resolve_expr(node->init, AST_CAN_BE_NULL);
-      resolve_and_require_bool("Conditional in a for loop condition", node->cond, AST_CAN_BE_NULL);
+      Operand op = resolve_expr(node->cond, AST_CAN_BE_NULL);
+      if(node->cond){
+        if((!node->init && !node->iter) && (is_array(op.type) || is_slice(op.type))){
+          node->is_array_traversal = true;
+          if(is_slice(op.type)) node->is_also_slice_traversal = true;
+          Ast_Decl *var = new_ast(Ast_Decl, AST_VAR, node->cond->pos, AST_DECL);
+          var->state = DECL_RESOLVED;
+          var->type = type_pointer(op.type->base);
+          var->name = intern_it;
+          insert_into_scope(node->parent_scope, var);
+          node->array_traversal_var = var;
+        }
+        else if(!is_bool(op.type)){
+          compiler_error(node->pos, "Invalid type of for loop condition %Q, required [Bool]", typestring(op.type));
+        }
+      }
+
       resolve_expr(node->iter, AST_CAN_BE_NULL);
       For(node->scope->stmts) resolve_stmt(it, ret);
       BREAK();