From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2007-12-21T20:30:38+09:00
Subject: Re: Problem with case statements

On Dec 21, 2007 12:14 PM, hemant kumar <gethemant@gmail.com> wrote:
> I have an innocent looking code:
>
> 54:    def find(*args)
> 55:      options = args.extract_options!
> 56:      validate_find_options(options)
> 57:      case args.first
> 58:      when :first: find_first(options)
> 59:      when :all: find_all(options)
> 60:      else raise "Invalid find"
> 61:      end
> 62:    end
>
>
> Now, above case statement totally blows up with Ruby 1.9:

My test is with Ruby 1.8.6 but:

>
> /home/hemant/push_server/bin/boot.rb:34:in
> `require': /home/hemant/push_server/lib/db_connection.rb:58: syntax
> error, unexpected ':', expecting keyword_then or ',' or ';' or
> '\n' (SyntaxError)
>       when :first: find_first(options)

if you want to put the body of the when in the same line you need a
then keyword:

irb(main):018:0> def find(*args)
irb(main):019:1> case args.first
irb(main):020:2> when :first then puts "first"
irb(main):021:2> when :all then puts "all"
irb(main):022:2> else raise "invalid"
irb(main):023:2> end
irb(main):024:1> end
=> nil
irb(main):025:0> find :first, 1, 2, 3, 4
first
=> nil

> However if i rewrite it like this, it works:
>
>     def find(*args)
>       options = args.extract_options!
>       validate_find_options(options)
>       case args.first
>       when :first
>         find_first(options)
>       when :all
>         find_all(options)
>       else
>         raise "Invalid find"
>       end
>     end
>
> Why is this? Was this intended?

From the pickaxe:

"The then keyword (or a colon) separates the when comparisons from the
bodies and is
not needed if the body starts on a new line."

Hope this helps,

Jesus.