From c5fa12f344b128b10213f326cfe1e4631a0b1673 Mon Sep 17 00:00:00 2001
From: Ian Price <ianprice90@googlemail.com>
Date: Wed, 16 Aug 2017 21:46:12 +0100
Subject: [PATCH] Implement variable-bound? builtin

* module/language/js-il/runtime.js(variable-bound?): Implement builtin
---
 module/language/js-il/runtime.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/module/language/js-il/runtime.js b/module/language/js-il/runtime.js
index 5591baa8e..786e6c3e3 100644
--- a/module/language/js-il/runtime.js
+++ b/module/language/js-il/runtime.js
@@ -1360,6 +1360,10 @@ def_guile0("make-undefined-variable", function (self, cont, val) {
     return cont(new scheme.Box(scheme.UNDEFINED));
 });
 
+def_guile0("variable-bound?", function (self, cont, box) {
+    return cont(coerce_bool(!(box.x === scheme.UNDEFINED)));
+});
+
 def_guile0("define!", function (self, cont, symbol, value) {
     // FIXME: validate symbol
     return cont(scm_module_define(scm_current_module(), symbol, value));