Implement atom evaluation

lib/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_library(imp
   am.c
   env.c
+  eval.c
   expr.c
   memory_stream.c
   parse.c

lib/eval.c

@@ -0,0 +1,19 @@
+#include "eval.h"
+
+#include "env.h"
+
+#include <assert.h>
+
+void eval(am_t *am)
+{
+	assert(am->expr->is_atom);
+	switch (am->expr->atom.type) {
+	case ATOM_TYPE_EMPTY_LIST:
+	case ATOM_TYPE_INTEGER:
+		am->val = am->expr;
+		break;
+	case ATOM_TYPE_SYMBOL:
+		env_fetch(am);
+		break;
+	}
+}

lib/include/eval.h

@@ -0,0 +1,8 @@
+#ifndef EVAL_H
+#define EVAL_H
+
+#include "am.h"
+
+void eval(am_t *am);
+
+#endif

tests/CMakeLists.txt

@@ -11,6 +11,7 @@ endfunction()
 add_test_suites(
   am_tests.c
   env_tests.c
+  eval_tests.c
   expr_tests.c
   parse_tests.c
   store_tests.c

tests/eval_tests.c

@@ -0,0 +1,66 @@
+#include "am.h"
+#include "env.h"
+#include "eval.h"
+#include "store.h"
+#include "unity.h"
+
+static am_t am;
+static store_t store;
+
+void setUp(void)
+{
+	am_init(&am);
+	store_init(&store);
+	env_init(&am, &store);
+}
+
+void tearDown(void)
+{
+}
+
+static void test_42_self_evals(void)
+{
+	am.expr = expr_integer(&store, 42);
+
+	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(42, am.val->atom.integer);
+}
+
+static void test_empty_list_self_evals(void)
+{
+	am.expr = expr_empty_list(&store);
+
+	eval(&am);
+
+	TEST_ASSERT_NOT_NULL(am.val);
+	TEST_ASSERT_TRUE(am.val->is_atom);
+	TEST_ASSERT_EQUAL(ATOM_TYPE_EMPTY_LIST, am.val->atom.type);
+}
+
+static void test_foo_evals_to_42_when_set_in_env(void)
+{
+	am.expr = expr_str_symbol(&store, "foo");
+	am.val = expr_integer(&store, 42);
+	env_set(&am, &store);
+	am.val = NULL;
+
+	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(42, am.val->atom.integer);
+}
+
+int main(void)
+{
+	UNITY_BEGIN();
+	RUN_TEST(test_42_self_evals);
+	RUN_TEST(test_empty_list_self_evals);
+	RUN_TEST(test_foo_evals_to_42_when_set_in_env);
+	return UNITY_END();
+}