From 0f8efe9693f3b39494fb21428766c70aa4e70360 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Sun, 10 Jan 2016 22:44:51 -0500
Subject: [PATCH] Added get-environment-variable

---
 scheme/process-context.sld | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/scheme/process-context.sld b/scheme/process-context.sld
index ba570bd5..03e8cac1 100644
--- a/scheme/process-context.sld
+++ b/scheme/process-context.sld
@@ -3,7 +3,7 @@
     command-line
     ;exit - already defined as a primitive, at least for now
     emergency-exit
-    ; TODO: get-environment-variable
+    get-environment-variable
     ; TODO: get-environment-variables
   )
 ;  (import (scheme base) 
@@ -28,4 +28,18 @@
           lis = pl;
         }
         return_closcall1(data, k, lis); ")
+    (define-c get-environment-variable
+      "(void *data, int argc, closure _, object k, object env_var)"
+      ;; TODO: consolidate with Cyc_command_line_arguments from runtime.c
+      " 
+        const char *v = NULL;
+        Cyc_check_str(data, env_var);
+        v = getenv(string_str(env_var));
+        if (v == NULL) {
+          return_closcall1(data, k, boolean_f);
+        } else {
+          make_string(str, v);
+          return_closcall1(data, k, &str);
+        }
+      ")
   ))