From: Guoliang Cao <gcao@...>
Date: 2004-02-05T03:00:04+09:00
Subject: Re: RCR draft for enhanced "case..when..else..end" syntax


---- Original Message ----
> Austin Ziegler wrote:
>> On Wed, 4 Feb 2004 01:00:25 +0900, Gennady wrote:
>> 
>>>Guoliang Cao wrote:
>>>Do you know about this syntax currently available?
>> 
>> 
>>>a = "aaa"
>>>b = "bbb"
>>>case
>>>  when a == "aaa", b == "bbb"
>>>    puts "Lowercase detected"
>>>  when a == "AAA", b == "BBB"
>>>    puts "Uppercase detected"
>>>  else
>>>    puts "Detection failed"
>>>end
>> 
>> 
>> What you've written here will do alternatives checks. Thus, if you have:
>> 
>> a = "aaa"
>> b = "BBB"
>> 
>> then "Lowercase detected" will be printed. With "AAA" and "bbb", "Lowercase
>> detected" will still be printed.

I think this is very tricky. ',' equals to '||' here. This should be made
very clear otherwise people should avoid use this form.

Cao


> Nice investigative job ;-). But remember that it was only a quick 
> demonstration of a "hidden" case syntax.

>> 
>> irb(main):001:0> def ct(a, b)
>> irb(main):002:1>   case
>> irb(main):003:2*     when a == "aaa", b == "bbb"
>> irb(main):004:2>       puts "Lowercase"
>> irb(main):005:2>     when a == "AAA", b == "BBB"
>> irb(main):006:2>       puts "Uppercase"
>> irb(main):007:2>     else
>> irb(main):008:2*       puts "Failed"
>> irb(main):009:2>   end
>> irb(main):010:1> end # => nil
>> irb(main):011:0> ct("aaa", "bbb") # Lowercase => nil
>> irb(main):012:0> ct("aaa", "BBB") # Lowercase => nil
>> irb(main):013:0> ct("AAA", "BBB") # Uppercase => nil
>> irb(main):014:0> ct("AAA", "bbb") # Lowercase => nil
>> 
>> -austin
>> --
>> austin ziegler    * austin@halostatue.ca * Toronto, ON, Canada
>> software designer * pragmatic programmer * 2004.02.04
>>                                          * 11.53.52
>> 
>> 
>> 

> Gennady.