From: Robert Klemme <shortcutter@...>
Date: 2008-09-08T20:47:24+09:00
Subject: Re: Ruby tailcall optimizes?

2008/9/8 cnb <circularfunc@yahoo.se>:
> Hmm this was a nice surprise. it seems Ruby does tailcall-
> optimization?

It doesn't.

13:51:03 ~$ ruby -e 'def t(a)a>0?t(a-1):a;end;t 1_000_000'
-e:1:in `t': stack level too deep (SystemStackError)
        from -e:1:in `t'
        from -e:1
13:51:39 ~$ ruby19 -e 'def t(a)a>0?t(a-1):a;end;t 1_000_000'
-e:1:in `t': stack level too deep (SystemStackError)
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
         ... 7264 levels...
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `t'
        from -e:1:in `<main>'

> Is there a way to have optional arguments in Ruby?

Did you read the documentation?

robert

-- 
use.inject do |as, often| as.you_can - without end