Implement atom evaluation

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;
+	}
+}