From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Sun, 13 Feb 2011 01:19:04 +0000 (+0000)
Subject: hostside: lib.tcl: new defset command
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ijackson/git?a=commitdiff_plain;h=d4eb17b6a7829d6cdb8a0a13b3000e2911835de7;p=trains.git

hostside: lib.tcl: new defset command
---

diff --git a/hostside/lib.tcl b/hostside/lib.tcl
index 8978343..c34fd84 100644
--- a/hostside/lib.tcl
+++ b/hostside/lib.tcl
@@ -86,5 +86,11 @@ proc setexpr {varname expr} {
     set var [uplevel 1 [list expr $expr]]
 }
 
+proc defset {varname val} {
+    upvar 1 $varname var
+    if {[info exists var]} return
+    set var $val
+}
+
 setting port 2883 {\d+}