From 1451bf7f8e32163ae4f7c05604317a747f65825b Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Mon, 24 Oct 2016 03:09:59 +0000
Subject: [PATCH] Added (library-exists?)

---
 scheme/cyclone/libraries.sld | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/scheme/cyclone/libraries.sld b/scheme/cyclone/libraries.sld
index 6b1efa3a..0c67fb1e 100644
--- a/scheme/cyclone/libraries.sld
+++ b/scheme/cyclone/libraries.sld
@@ -20,6 +20,7 @@
   )
   (export
     library?
+    library-exists?
     lib:list->import-set
     lib:name
     lib:name->string
@@ -60,6 +61,13 @@
 
 (define (library? ast)
   (tagged-list? 'define-library ast))
+ 
+;; Determine if a library exists for the given import set
+(define (library-exists? import . ext)
+  (file-exists?
+    (lib:import->filename 
+      (lib:import->library-name import)
+      (if (null? ext) ".sld" (car ext)))))
 
 ;; Convert a raw list to an import set. For example, a list might be
 ;; (srfi 18) containing the number 18. An import set contains only symbols