From: Mark Hubbart <discord@...>
Date: 2004-09-28T04:21:49+09:00
Subject: Re: [Ruby Forum] irb feature suggestion


On Sep 27, 2004, at 12:13 PM, Alexey Verkhovsky wrote:

> Cross-posted from Ruby Forum:
> http://www.ruby-forum.org/bb/viewtopic.php?t=62
>
> ----
>
> How do you get the value of the last expression entered in irb?
>
> SML/NJ puts it in the variable 'it', Python uses '_', I think.
> So you can do something like this:
> Code:
>> 6*9
> => it = 54
>> it - 12
> => it = 42
>
> Can you do this in Irb? It's very useful for evaluating expressions
> interactively, without cluttering up your symbol table (e.g. when
> evaluating something piece-by-piece to see how it's working.)
>
> For example, I just did
> Code:
> YAML::load(<<END)
> # ... some YAML here ...
> END
> and got the right result, then realised I had no way of using it.

I distinctly remembered this one from a few months back...

In ruby-talk:102888, Nobu Nakada said:

> EVAL_HISTORY enables _.
>
> $ grep HISTORY ~/.irbrc
> IRB.conf[:EVAL_HISTORY] = 1000
> IRB.conf[:SAVE_HISTORY] = 100
>
> $ irb
> irb(main):001:0> 2+2
> => 4
> irb(main):002:0> _
> => 4
> irb(main):003:0>
>
> -- 
> Nobu Nakada


So, just add those lines to your ~/.irbrc, and that's it.

HTH,
Mark