Monday, November 28, 2016


AnyBar is a macOS status indicator that displays a "colored dot" in the menu bar that can be changed programatically. What it means and when it changes is entirely up to the user.

You can easily install it with Homebrew-cask:

$ brew cask install anybar

The README lists a number of alternative clients in different programming languages. I thought it would be fun to show how to use it from Factor. Since AnyBar responds to AppleScript (and I added support for AppleScript a few years ago), we could do this:


"tell application \"AnyBar\" to set image name to \"blue\""

The AnyBar application also listens to a UDP port (default: 1738) and can be instructed to change from a Terminal using a simple echo | nc command:

$ echo -n "blue" | nc -4u -w0 localhost 1738

Using our networking words similarly is pretty simple:

"blue" >byte-array "" 1738 <inet4> send-once

But if we wanted to get more fancy, we could use symbols to configure which AnyBar instance to send to, with default values to make it easy to use, and resolve-host to lookup hostnames:

SYMBOL: anybar-host
"localhost" anybar-host set-global

SYMBOL: anybar-port
1738 anybar-port set-global

: anybar ( str -- )
    ascii encode
    anybar-host get resolve-host first
    anybar-port get with-port send-once ;

AnyBar is a neat little program!

Saturday, November 26, 2016

Reverse Factorial

A few years ago, I wrote about implementing various factorials using Factor. Recently, I came across a programming challenge to implement a "reverse factorial" function to determine what factorial produces a number, or none if it is not a factorial.

To do this, we examine each factorial in order, checking against the number being tested:

: reverse-factorial ( m -- n )
    1 1 [ 2over > ] [ 1 + [ * ] keep ] while [ = ] dip and ;

And some unit tests:

{ 10 } [ 3628800 reverse-factorial ] unit-test
{ 12 } [ 479001600 reverse-factorial ] unit-test
{ 3 } [ 6 reverse-factorial ] unit-test
{ f } [ 18 reverse-factorial ] unit-test