+# generate a regex from a shell type expression
+# see 'perl cookbook' 6.9
+sub shellregex
+{
+ my $in = shift;
+ $in =~ s{(.)} { $patmap{$1} || "\Q$1" }ge;
+ return '^' . $in . "\$";
+}
+
+# start an attempt at determining whether this string might be a callsign
+sub iscallsign
+{
+ my $call = shift;
+ return 1 if $call =~ /^\w+\d+/;
+ return 1 if $call =~ /^\d+\w+/;
+ return undef;
+}