Perl Goodbye World

Here we present the same "Goodbye World" WAFE application, but this time driven by a separate Perl process rather than directly from a WAFE script file: This is the configuration in which all remaining examples will be run.

#!/usr/local/bin/perl

# Tell Perl where to look for wafe-specific libraries:
$WafeLib = $ENV{'WAFELIB'} || "/usr/local/lib/wafe";

# Load a library of wafe-specific convenience functions:
require "$WafeLib/perl/wafe.pl";

# Feed the widget definitions to WAFE via stdout.
# We use Xui, which is one of the wafe.pl convenience
# functions: It simply sends all given text to
# stdout and thence to the WAFE process.
# Note we need \\ not \ at end of line here:
&Xui(<<"End_Tcl");
    Command c topLevel \\
        label "Goodbye World!" \\
        callback {puts Goodbye; quit}
    realize
End_Tcl

# Loop reading and respond to
# callback-generated text from
# the WAFE process, read via
# stdin using another wafe.pl
# convenience function:
while ($_ = &wafe'read) {
    last if /^Goodbye/;
}

(For clarity, we have made the above example both more verbose than one would normally, and also somewhat more general than needed by this example, so as to show a more typical application structure.)

Create a textfile "goodbye" containing the above text, and make it executable by doing

chmod +x ./goodbye

at the unix prompt.

You may now invoke this new version by doing

/usr/local/bin/wafe --p `pwd`/goodbye

at the unix prompt.