The most voted Ruby question on Stack Overflow

http://stackoverflow.com/questions/948135/how-can-i-write-a-switch-statement-in-ruby

by izietto • 13 years ago

7 19 13 years ago

Leads to "How can I write a switch statement in Ruby?"

izietto3• 13 years ago

Yes, it seems to me quite ironic (and weird) that the most voted Ruby question on StackOverflow asks for how to write a switch!

dasil0032• 13 years ago

What's ironic about it? What would you expect to be the most voted ruby question?

x3ro• 13 years ago

How on earth did this get to the front page? :D

stef25• 13 years ago

Is there no equivalent of php.net that explains this simple control structure?

masklinn2• 13 years ago

The ruby community does not really believe in documentation, so you have to go for third-party sources[0] or books

Also, it's not a simple control structure, Ruby's case/when does not do equality checks (via ==) it does match checks (via ===) so you can match integers to ranges:

    > (1..3) === 2
    => true

or instances to classes

    > String === "foo"
    => true

But `===` is not commutative:

    > 2 === (1..3) 
    => false

and the matches can seem somewhat arbitrary:

    > (1..5) === (2..3)
    => false

[0] http://www.techotopia.com/index.php/The_Ruby_case_Statement

k__2• 13 years ago

The ruby community does not really believe in documentation

made my day, thanks.

achivetta• 13 years ago

Is this perhaps because ruby calls it a case statement instead of a switch statement?

matthewmacleod• 13 years ago

Ruby's case statements are super-awesome, and I constantly find myself longing for similar sugar elsewhere. Obviously it's more useful in a duck-typed language.

RubySpec, for those who aren't familiar with it, is an attempt to write an executable specification for the language. Ruby's definitely suffered from not having this in the past. https://github.com/rubyspec/rubyspec/ and specifically case statement spec at https://github.com/rubyspec/rubyspec/blob/master/language/ca...

masklinn2• 13 years ago

Ruby's case statements are super-awesome

Most functional languages have, I think, somewhat better systems in that there's less magic[0], you can unwrap/extract values and you can add further conditions on values (guards)[1][2][3].

Some modern multiparadigm languages have lifted this style e.g. Scala or Rust.

[0] because case/when relies on the non-commutative `===` its behavior can be surprising

[1] http://learnyouahaskell.com/syntax-in-functions#case-express...

[2] http://learnyousomeerlang.com/syntax-in-functions#in-case-of

[3] http://en.wikibooks.org/wiki/F_Sharp_Programming/Pattern_Mat...

The most voted Ruby question on Stack Overflow

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