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