Handle argument evaluation

lib/eval.c

@@ -20,9 +20,29 @@ static void eval_atom(am_t *am)
 
 static void eval_list(am_t *am)
 {
-	am->argl = am->expr->pair.cdr;
+	am->argl = expr_empty_list(am);
+	am->unev = am->expr->pair.cdr;
 	am->expr = am->expr->pair.car;
 
+	while (!am->unev->is_atom) {
+		am_push(am);
+		am->expr = am->unev->pair.cdr;
+		am_push(am);
+		am->expr = am->argl;
+		am_push(am);
+
+		am->expr = am->unev->pair.car;
+		eval(am);
+
+		am_pop(am);
+		am->argl = am->expr;
+		am_append_arg(am);
+
+		am_pop(am);
+		am->unev = am->expr;
+		am_pop(am);
+	}
+
 	assert(am->expr->is_atom);
 	assert(am->expr->atom.type == ATOM_TYPE_SYMBOL);
 	env_fetch(am);

lib/include/am.h

@@ -7,7 +7,7 @@
 #define AM_STACK_SIZE 128U
 
 typedef struct am {
-	expr_t *argl, *env, *expr, *val;
+	expr_t *argl, *env, *expr, *unev, *val;
 	expr_t **sp, *stack[AM_STACK_SIZE];
 	store_t store;
 } am_t;

tests/eval_tests.c

@@ -88,6 +88,31 @@ static void test_add_1_2_3_evals_to_6(void)
 	TEST_ASSERT_EQUAL(6, am.val->atom.integer);
 }
 
+static void test_add_1_mul_2_3_evals_to_7(void)
+{
+	am.expr = expr_pair(
+	    &am, expr_str_symbol(&am, "+"),
+	    expr_pair(
+	        &am, expr_integer(&am, 1),
+	        expr_pair(
+	            &am,
+	            expr_pair(
+	                &am, expr_str_symbol(&am, "*"),
+	                expr_pair(
+	                    &am, expr_integer(&am, 2),
+	                    expr_pair(
+	                        &am, expr_integer(&am, 3),
+	                        expr_empty_list(&am)))),
+	            expr_empty_list(&am))));
+
+	eval(&am);
+
+	TEST_ASSERT_NOT_NULL(am.val);
+	TEST_ASSERT_TRUE(am.val->is_atom);
+	TEST_ASSERT_EQUAL(ATOM_TYPE_INTEGER, am.val->atom.type);
+	TEST_ASSERT_EQUAL(7, am.val->atom.integer);
+}
+
 int main(void)
 {
 	UNITY_BEGIN();
@@ -96,5 +121,6 @@ int main(void)
 	RUN_TEST(test_prim_proc_self_evals);
 	RUN_TEST(test_foo_evals_to_42_when_set_in_env);
 	RUN_TEST(test_add_1_2_3_evals_to_6);
+	RUN_TEST(test_add_1_mul_2_3_evals_to_7);
 	return UNITY_END();
 }