Add reduce and filter

src/builtins.c

@@ -196,6 +196,33 @@ LISP_FUNC_2(ucl_builtin_mapcar, scope, fun, elems) {
     return result;
 }
 
+LISP_FUNC_2(ucl_builtin_filter, scope, predicate, elems) {
+    // TODO: Support arbitrary number of 'elems' lists
+    struct ucl_object *result = ucl_nil_create();
+    struct ucl_object *result_tail = result;
+    FOREACH_LIST(elems, iter, elem) {
+        struct ucl_object *form = ucl_tuple_create(predicate, elem);
+        struct ucl_object *value = ucl_evaluate(scope, form);
+        UCL_RET_IF_ERROR(value);
+        if (ucl_truthy_bool(value)) {
+            result_tail = ucl_list_append(result_tail, elem);
+        }
+    }
+    return result;
+}
+
+LISP_FUNC_3(ucl_builtin_reduce, scope, fun, elems, initial_value) {
+    // TODO: Support arbitrary number of 'elems' lists
+    struct ucl_object *result = initial_value;
+    FOREACH_LIST(elems, iter, elem) {
+        struct ucl_object *form = ucl_tuple_create(fun, elem);
+        ucl_list_append(form, result);
+        result = ucl_evaluate(scope, form);
+        UCL_RET_IF_ERROR(result);
+    }
+    return result;
+}
+
 LISP_FUNC_2(ucl_builtin_equal, scope, arg0, arg1) {
     return ucl_equal(arg0, arg1);
 }
@@ -212,7 +239,6 @@ LISP_FUNC_2(ucl_builtin_ge, scope, arg0, arg1) {
     return ucl_predicate(arg0->integer > arg1->integer);
 }
 
-
 LISP_FUNC_2(ucl_builtin_lt, scope, arg0, arg1) {
     UCL_COND_OR_RET_ERROR(arg0->type == UCL_TYPE_INT, "First argument to < must be an integer");
     UCL_COND_OR_RET_ERROR(arg0->type == UCL_TYPE_INT, "Second argument to < must be an integer");

src/builtins.h

@@ -32,6 +32,8 @@ struct ucl_object *ucl_builtin_cdr(struct ucl_scope *scope, struct ucl_object *a
 struct ucl_object *ucl_builtin_nth(struct ucl_scope *scope, struct ucl_object *args);
 struct ucl_object *ucl_builtin_list(struct ucl_scope *scope, struct ucl_object *args);
 struct ucl_object *ucl_builtin_mapcar(struct ucl_scope *scope, struct ucl_object *args);
+struct ucl_object *ucl_builtin_filter(struct ucl_scope *scope, struct ucl_object *args);
+struct ucl_object *ucl_builtin_reduce(struct ucl_scope *scope, struct ucl_object *args);
 struct ucl_object *ucl_builtin_append(struct ucl_scope *scope, struct ucl_object *args);
 
 struct ucl_object *ucl_builtin_print(struct ucl_scope *scope, struct ucl_object *args);

src/lisp.h

@@ -46,4 +46,23 @@
     }                                                                   \
     static struct ucl_object *func_name##_impl(struct ucl_scope *scope, struct ucl_object *arg0_name, struct ucl_object *arg1_name)
 
+// TODO: Unroll the args more efficiently, this is O(n^2)
+#define LISP_FUNC_3(func_name, scope_name, arg0_name, arg1_name, arg2_name)        \
+    static struct ucl_object *func_name##_impl(struct ucl_scope *scope, struct ucl_object *arg0_name, struct ucl_object *arg1_name, struct ucl_object *arg2_name); \
+    struct ucl_object *func_name(struct ucl_scope *scope, struct ucl_object *args) { \
+        struct ucl_object *len_obj = ucl_list_length(args);             \
+        if (len_obj->type != UCL_TYPE_INT) {                            \
+            return NULL;                                                \
+        }                                                               \
+        if (len_obj->integer != 3) {                                    \
+            return NULL;                                                \
+        }                                                               \
+        struct ucl_object *arg0 = ucl_list_nth(args, 0);                \
+        struct ucl_object *arg1 = ucl_list_nth(args, 1);                \
+        struct ucl_object *arg2 = ucl_list_nth(args, 2);                \
+        return func_name##_impl(scope_name, arg0, arg1, arg2);          \
+    }                                                                   \
+    static struct ucl_object *func_name##_impl(struct ucl_scope *scope, struct ucl_object *arg0_name, struct ucl_object *arg1_name, struct ucl_object *arg2_name)
+
+
 #endif

src/main.c

@@ -60,6 +60,8 @@ int main(int argc, const char **argv) {
     ucl_scope_put(scope, "cdr", ucl_builtin_create(ucl_builtin_cdr));
     ucl_scope_put(scope, "nth", ucl_builtin_create(ucl_builtin_nth));
     ucl_scope_put(scope, "mapcar", ucl_builtin_create(ucl_builtin_mapcar));
+    ucl_scope_put(scope, "filter", ucl_builtin_create(ucl_builtin_filter));
+    ucl_scope_put(scope, "reduce", ucl_builtin_create(ucl_builtin_reduce));
     ucl_scope_put(scope, "equal", ucl_builtin_create(ucl_builtin_equal));
     ucl_scope_put(scope, "append", ucl_builtin_create(ucl_builtin_append));
 
@@ -67,10 +69,6 @@ int main(int argc, const char **argv) {
     ucl_scope_put(scope, "dolist", ucl_special_create(ucl_special_dolist));
     ucl_scope_put(scope, "while", ucl_special_create(ucl_special_while));
 
-    // TODO:
-    //   - reduce
-    //   - filter
-
     if (argc < 2) {
         while (1) {
             char *line = readline("> ");

test/test_e2e.c

@@ -29,8 +29,11 @@ void setUp(void) {
     ucl_scope_put(scope, "cdr", ucl_builtin_create(ucl_builtin_cdr));
     ucl_scope_put(scope, "nth", ucl_builtin_create(ucl_builtin_nth));
     ucl_scope_put(scope, "mapcar", ucl_builtin_create(ucl_builtin_mapcar));
+    ucl_scope_put(scope, "filter", ucl_builtin_create(ucl_builtin_filter));
+    ucl_scope_put(scope, "reduce", ucl_builtin_create(ucl_builtin_reduce));
     ucl_scope_put(scope, "lambda", ucl_special_create(ucl_special_lambda));
     ucl_scope_put(scope, "quote", ucl_special_create(ucl_special_quote));
+    ucl_scope_put(scope, "%", ucl_builtin_create(ucl_builtin_mod));
 }
 
 void tearDown(void) {
@@ -226,6 +229,16 @@ void test_eval_defun_gc(void) {
     TEST_ASSERT_OBJ_INT_V(response, 25);
 }
 
+void test_complex(void) {
+    response = eval("(defun sum (elems) (reduce (quote +) elems 0))");
+
+    TEST_ASSERT_OBJ_SYMBOL_V(response, "sum");
+
+    response = eval("(sum (filter (quote (lambda (x) (% x 2))) (list 1 2 3 4 5)))");
+
+    TEST_ASSERT_OBJ_INT_V(response, 9);
+}
+
 int main(void) {
     UNITY_BEGIN();
 
@@ -254,6 +267,7 @@ int main(void) {
     RUN_TEST(test_nth_1);
     RUN_TEST(test_nth_oob);
     RUN_TEST(test_eval_defun_gc);
+    RUN_TEST(test_complex);
 
     return UNITY_END();
 }