Question

I’m working on implementing Project Euler solutions as semantic Ruby one-liners. It would be extremely useful if I could coerce Ruby to automatically puts the value of the last expression. Is there a way to do this? For example:

#!/usr/bin/env ruby -Ilib -rrubygems -reuler

1.upto(100).into {|n| (n.sum.squared - n.map(&:squared).sum)

I realize I can simply puts the line, but for other reasons (I plan to eval the file in tests, to compare against the expected output) I would like to avoid an explicit puts. Also, it allots me an extra four characters for the solution. 🙂

Is there anything I can do?

Answer 1

You might try running it under irb instead of directly under a Ruby interpreter.

It seems like the options -f --noprompt --noverbose might be suitable (.

#!/usr/bin/env irb -f --noprompt --noverbose -Ilib -rrubygems -reuler

'put your one-liner here'

The options have these meanings:

• -f: do not use .irbrc (or IRBRC)
• --noverbose: do not display the source lines
• --noprompt: do not prefix the output (e.g. with =>)