From: Phillip Gawlowski <cmdjackryan@...>
Date: 2011-07-19T07:43:12+09:00
Subject: Re: Question about Ruby Gems

On Tue, Jul 19, 2011 at 12:17 AM, Tyrel R. <tyrelrichey@gmail.com> wrote:
> Am I wrong in the understanding that the ruby gems that add
> functionality to ruby do it by wrapping c programs with ruby syntax
> somehow.

Yes and no. RubyGems *can* be used to distribute gems that include
C/++/Java/.NET extensions (Java and .NET for JRuby an IronRuby,
respectively), but they don't *have* to.

There's plenty of gems that are pure Ruby libraries, as well (I'm
quite sure that the vast majority of libraries meets that, actually).


> And if this is the case is there much of a difference between
> using a gem like RMagick and just doing a system call:
>
>  system 'rmagick comand'
>

The difference is like using a single LEGO brick (farming out to the
command line), or a couple of them to build something new (using the
pg gem to access a PostgreSQL database, use the RMagick gem to
generate a map with GPS data, and  the Prawn gem to write a PDF).

Sure, you can do all that from a command line, but that can be costly,
brittle, or both.

-- 
Phillip Gawlowski

phgaw.posterous.com | twitter.com/phgaw | gplus.to/phgaw

A method of solution is perfect if we can forsee from the start,
and even prove, that following that method we shall attain our aim.
              -- Leibniz