Filler

Apr 25 2008

If you’re not smart enough to program, don’t write a programming guide

Published by Nerdmaster at 1:22 am under Bad Programmer!, Opinions, Programming

I can’t believe this. Simply amazing.

I really can’t.

I’m not even sure this is good enough to fall under my usual “Awesome Software Discovery” banner.

So I work at a place where we use Ruby and Perl a lot, right? The above site is supposedly a “conversion” of O’Rielly’s Perl Cookbook into Ruby. Good idea. But here’s the thing - if you don’t know your ass from a hole in the ground, maybe you shouldn’t be writing a programming guide. Maybe. I don’t know. Am I being too harsh?

The introduction shows this example:

# $defout (or its synonym '$>') is the destination of output
# for Kernel#print, Kernel#puts, and family functions
logfile = File.new("log.txt", "w")
old = $defout
$defout = logfile                 # switch to logfile for output
puts "Countdown initiated ..."
$defout = old                     # return to original output
puts "You have 30 seconds to reach minimum safety distance."

There is no fucking excuse for this kind of programming style. Even a total noob should look at this and say, “What the fuck?”

Yes, sometimes you need to redirect output or errors to a file… but the introduction doesn’t explain that this is an exception rather than a rule.
Redirecting $defout is very dangerous if the developer doesn’t fully understand 100% of what they’re writing, and the libraries they’re using. (And if they need a perl-to-ruby cookbook, chances are they don’t understand 100% of what they’re writing)
Maybe I’m misreading something, but isn’t it significantly safer in an app more than 3 lines long to call .dup on $stdout / $defout when saving the old value? (The answer is “yes,” for my less astute readers)

In any case, here’s how you write to a file in Ruby without making the guy who reviews your code cringe and then stab you in the fucking eye (note that it’s not only safer, but also easier to read and generally doesn’t make you look like a moron):

# $defout, $stdout, and other magic variables are NOT TOUCHED!
logfile = File.new("log.txt", "w")
logfile.puts "Countdown initiated..."
puts "You have 30 seconds blah blah I'm a monkey licker."

Neat!