impl a bunch of builtins

builtins.c

@@ -1,7 +1,7 @@
 #include "lisp.h"
 
 Node *lisp_function_addition(Nodes *args, Scopes *scopes) {
-    (void)(scopes);
+    UNUSED(scopes);
 
     if (args->count != 2) {
         printf("'+' expects two arguments!\n");
@@ -35,3 +35,79 @@ Node *lisp_function_println(Nodes *args, Scopes *scopes) {
 
     return result;
 }
+
+Node *lisp_function_list(Nodes *args, Scopes *scopes) {
+    UNUSED(scopes);
+
+    Node *node = malloc(sizeof(Node));
+    node->kind = NODE_KIND_LIST;
+    node->as_list = args;
+    return node;
+}
+
+Node *lisp_function_append(Nodes *args, Scopes *scopes) {
+    UNUSED(scopes);
+
+    if (args->count != 2) {
+        printf("'append' expects two arguments!\n");
+        return NULL;
+    }
+
+    Node *node = malloc(sizeof(Node));
+    node->kind = NODE_KIND_LIST;
+
+    if (args->items[0].kind != NODE_KIND_LIST ||
+        args->items[1].kind != NODE_KIND_LIST) {
+        printf("'append' can only append two lists!\n");
+        return NULL;
+    }
+
+    Nodes *nodes = malloc(sizeof(Nodes));
+
+    Nodes *a = args->items[0].as_list;
+    nob_da_append_many(nodes, a->items, a->count);
+
+    Nodes *b = args->items[1].as_list;
+    nob_da_append_many(nodes, b->items, b->count);
+
+    node->as_list = nodes;
+    return node;
+}
+
+Node *lisp_function_length(Nodes *args, Scopes *scopes) {
+    UNUSED(scopes);
+
+    if (args->count != 1) {
+        printf("'length' expects one argument!\n");
+        return NULL;
+    }
+
+    if (args->items[0].kind != NODE_KIND_LIST) {
+        printf("'length' can only be used on lists!\n");
+        return NULL;
+    }
+
+    Node *node = malloc(sizeof(Node));
+    node->kind = NODE_KIND_NUMBER;
+    node->as_number = args->items[0].as_list->count;
+    return node;
+}
+
+Node *lisp_function_isnull(Nodes *args, Scopes *scopes) {
+    UNUSED(scopes);
+
+    if (args->count != 1) {
+        printf("'null?' expects one argument!\n");
+        return NULL;
+    }
+
+    if (args->items[0].kind != NODE_KIND_LIST) {
+        printf("'null?' can only be used on lists!\n");
+        return NULL;
+    }
+
+    Node *node = malloc(sizeof(Node));
+    node->kind = NODE_KIND_NUMBER;
+    node->as_number = args->items[0].as_list->count == 0 ? 1 : 0;
+    return node;
+}

lisp.c

@@ -15,39 +15,24 @@ static Node *scope_lookup(Scopes *scopes, Nob_String_View name) {
     return NULL;
 }
 
-void build_scopes(Scopes *scopes) {
-    // clang-format off
-    Nob_String_View obj_name = (Nob_String_View){
-        .items = "+",
-        .count = 1
-    };
+static void scope_add_function(Scope *scope, const char *name,
+                               LispFunction function) {
+    Nob_String_View obj_name = nob_sv_from_cstr(name);
     ScopeObject obj = (ScopeObject){
         .name = obj_name,
-        .node = (Node){
-            .kind = NODE_KIND_FUNCTION,
-            .as_function = {
-                .name = obj_name,
-                .apply = lisp_function_addition
-            }
-        }
-    };
-    nob_da_append(&globalScope, obj);
+        .node = (Node){.kind = NODE_KIND_FUNCTION,
+                       .as_function = {.name = obj_name, .apply = function}}};
+    nob_da_append(scope, obj);
+}
 
-    obj_name = (Nob_String_View){
-        .items = "println",
-        .count = 7
-    };
-    obj = (ScopeObject){
-        .name = obj_name,
-        .node = (Node){
-            .kind = NODE_KIND_FUNCTION,
-            .as_function = {
-                .name = obj_name,
-                .apply = lisp_function_println
-            }
-        }
-    };
-    nob_da_append(&globalScope, obj);
+void build_scopes(Scopes *scopes) {
+    // clang-format off
+    scope_add_function(&globalScope, "+", lisp_function_addition);
+    scope_add_function(&globalScope, "println", lisp_function_println);
+    scope_add_function(&globalScope, "list", lisp_function_list);
+    scope_add_function(&globalScope, "append", lisp_function_append);
+    scope_add_function(&globalScope, "length", lisp_function_length);
+    scope_add_function(&globalScope, "null?", lisp_function_isnull);
     // clang-format on
 
     nob_da_append(scopes, globalScope);

lisp.h

@@ -82,5 +82,9 @@ Node *eval(Node *node, Scopes *scopes);
 // builtins
 Node *lisp_function_addition(Nodes *args, Scopes *scopes);
 Node *lisp_function_println(Nodes *args, Scopes *scopes);
+Node *lisp_function_list(Nodes *args, Scopes *scopes);
+Node *lisp_function_append(Nodes *args, Scopes *scopes);
+Node *lisp_function_length(Nodes *args, Scopes *scopes);
+Node *lisp_function_isnull(Nodes *args, Scopes *scopes);
 
 #endif // LISP_H