add default_arg proc, for writing nicer code

svn path=/trunk/externals/tclpd/; revision=12204

1 files changed, 8 insertions, 0 deletions

diff --git a/pdlib.tcl b/pdlib.tcl
index 4c3a63e..2f97b03 100644
--- a/pdlib.tcl
+++ b/pdlib.tcl
@@ -174,6 +174,14 @@ namespace eval ::pd {
         }
     }
 
+    proc default_arg {n assertion defval} {
+        if {$n < [uplevel "pd::args"]} {
+            return [uplevel "pd::arg $n $assertion"]
+        } else {
+            return $defval
+        }
+    }
+
     # mechanism for uploading procs to gui interp, without the hassle of escaping [encoder]
     proc guiproc {name argz body} {
         # upload the decoder