feat: quote, nth

builtins.c

@@ -193,3 +193,33 @@ int builtin_ceil(Nodes args, Scopes *scopes, Node *result) {
     result->as_number = ceil(args.items[0].as_number);
     return 0;
 }
+
+int builtin_nth(Nodes args, Scopes *scopes, Node *result) {
+    UNUSED(scopes);
+
+    if (args.count != 2) {
+        printf("'nth' expects two arguments!\n");
+        return 1;
+    }
+
+    Node node_idx = args.items[0];
+    if (node_idx.kind != NODE_KIND_NUMBER) {
+        printf("'nth' expects an index as the first argument!\n");
+        return 1;
+    }
+
+    Node node_list = args.items[1];
+    if (node_list.kind != NODE_KIND_LIST) {
+        printf("'nth' expects a list as the second argument!\n");
+        return 1;
+    }
+
+    uint64_t idx = node_idx.as_number;
+    if (idx >= node_list.as_list->count) {
+        printf("Index out of bounds!");
+        return 1;
+    }
+
+    *result = node_list.as_list->items[idx];
+    return 0;
+}

lisp.c

@@ -13,6 +13,10 @@ static LispFunction special_forms[] = {
     {
         .name = (Nob_String_View){.count = 6, .data = "lambda"},
         .apply = special_form_lambda,
+    },
+    {
+        .name = (Nob_String_View){.count = 5, .data = "quote"},
+        .apply = special_form_quote,
     }};
 
 static int scope_lookup(Scopes *scopes, Nob_String_View name, Node *result) {
@@ -49,16 +53,17 @@ void build_scopes(Scopes *scopes) {
     scope_add_function(&global_scope, ">", builtin_gt);
     scope_add_function(&global_scope, "<=", builtin_lt_eq);
     scope_add_function(&global_scope, ">=", builtin_gt_eq);
+    scope_add_function(&global_scope, "floor", builtin_floor);
+    scope_add_function(&global_scope, "ceil", builtin_ceil);
 
-    scope_add_function(&global_scope, "println", builtin_println);
     scope_add_function(&global_scope, "list", builtin_list);
     scope_add_function(&global_scope, "append", builtin_append);
     scope_add_function(&global_scope, "length", builtin_length);
     scope_add_function(&global_scope, "null?", builtin_isnull);
-    scope_add_function(&global_scope, "builtins", builtin_builtins);
+    scope_add_function(&global_scope, "nth", builtin_nth);
 
-    scope_add_function(&global_scope, "floor", builtin_floor);
-    scope_add_function(&global_scope, "ceil", builtin_ceil);
+    scope_add_function(&global_scope, "println", builtin_println);
+    scope_add_function(&global_scope, "builtins", builtin_builtins);
 
     nob_da_append(scopes, &global_scope);
 }

lisp.h

@@ -105,27 +105,30 @@ int special_form_if(Nodes args, Scopes *scopes, Node *result);
 int special_form_define(Nodes args, Scopes *scopes, Node *result);
 int special_form_let(Nodes args, Scopes *scopes, Node *result);
 int special_form_lambda(Nodes args, Scopes *scopes, Node *result);
+int special_form_quote(Nodes args, Scopes *scopes, Node *result);
 
 // builtins
 int builtin_add(Nodes args, Scopes *scopes, Node *result);
-int builtin_sub(Nodes args, Scopes *scope, Node *result);
-int builtin_div(Nodes args, Scopes *scope, Node *result);
-int builtin_mul(Nodes args, Scopes *scope, Node *result);
-
-int builtin_eq(Nodes args, Scopes *scope, Node *result);
-int builtin_lt(Nodes args, Scopes *scope, Node *result);
-int builtin_gt(Nodes args, Scopes *scope, Node *result);
-int builtin_lt_eq(Nodes args, Scopes *scope, Node *result);
-int builtin_gt_eq(Nodes args, Scopes *scope, Node *result);
-
-int builtin_println(Nodes args, Scopes *scopes, Node *result);
-int builtin_list(Nodes args, Scopes *scopes, Node *result);
-int builtin_append(Nodes args, Scopes *scope, Node *result);
-int builtin_length(Nodes args, Scopes *scope, Node *result);
-int builtin_isnull(Nodes args, Scopes *scope, Node *result);
-int builtin_builtins(Nodes args, Scopes *scopes, Node *result);
+int builtin_sub(Nodes args, Scopes *scopes, Node *result);
+int builtin_div(Nodes args, Scopes *scopes, Node *result);
+int builtin_mul(Nodes args, Scopes *scopes, Node *result);
 
 int builtin_floor(Nodes args, Scopes *scopes, Node *result);
 int builtin_ceil(Nodes args, Scopes *scopes, Node *result);
 
+int builtin_eq(Nodes args, Scopes *scopes, Node *result);
+int builtin_lt(Nodes args, Scopes *scopes, Node *result);
+int builtin_gt(Nodes args, Scopes *scopes, Node *result);
+int builtin_lt_eq(Nodes args, Scopes *scopes, Node *result);
+int builtin_gt_eq(Nodes args, Scopes *scopes, Node *result);
+
+int builtin_list(Nodes args, Scopes *scopes, Node *result);
+int builtin_append(Nodes args, Scopes *scopes, Node *result);
+int builtin_length(Nodes args, Scopes *scopes, Node *result);
+int builtin_isnull(Nodes args, Scopes *scopes, Node *result);
+int builtin_nth(Nodes args, Scopes *scopes, Node *result);
+
+int builtin_println(Nodes args, Scopes *scopes, Node *result);
+int builtin_builtins(Nodes args, Scopes *scopes, Node *result);
+
 #endif // LISP_H

special_forms.c

@@ -168,3 +168,16 @@ int special_form_lambda(Nodes args, Scopes *scopes, Node *result) {
     result->as_lambda.body = body;
     return 0;
 }
+
+int special_form_quote(Nodes args, Scopes *scopes, Node *result) {
+    UNUSED(scopes);
+
+    if (args.count != 1) {
+        printf("'quote' expects one argument!\n");
+        return 1;
+    }
+
+    Node n = args.items[0];
+    *result = n;
+    return 0;
+}