I'm quickly learning ruby at my new job. Today's POLA (principle of least astonishment) violation is blamed on my expectations of 'if' behavior in Ruby from what I know from Python, C, and other languages.

Non-nil values are considered true:

["0", [], {}, "", 0, true, false, nil].each { |x|
  bool = (x) ? true : false
  puts "#{x.inspect}: #{bool}"
}

"0": true
[]: true
{}: true
"": true
0: true
true: true
false: false
nil: false

I mostly expected every one of the outputs here except for the literal 0 value being true. Noted for future reference.

Additionally confusing, is that Integer() will barf on most non-number inputs, but for some reason "nil" means 0.

irb(main):002:0> Integer(nil)
=> 0

Unexpected.

I love perl's (?{ code }) feature. I want it in other languages.

I spent some time on hacking this into ruby a few weeks ago. I finally got around to making patches.

In FreeBSD ports, I select to build Ruby 1.8.6 with oniguruma for the regex engine. After doing 'make configure' you can apply these patches:

• patch-ruby1.8.6-regcomp.c
• patch-ruby1.8.6-regexec.c
• patch-ruby1.8.6-regparse.c

I haven't tested this on other platforms, and it's not feature complete, but it's close.

Last night, I mentioned that I wanted (?{ code }) in ruby and python.

I got bored tonight and decided to see how hard this would be to implement in ruby. Turns out it's not as bad as I thought, not that I'm finished yet.

This ruby script shows a demo of what I have so far. The output is in comments in the script. There's a few strange bugs yet, but I've nearly got it working properly. Something about my coding or the way oniguruma does backtracking/failures keeps this from working correctly on strings with multiple potential matches.

Dear Ruby and Python,

Please implement Perl's (?{}) and (??{}) in your regular expression engines so I can do outrageous state machine and pattern matching in your languages. Thank you.

Love,
Jordan