Re: Are there two kinds of 'require' ?

On Nov 5, 2011, at 1:26 PM, Kaye Ng wrote:

> I'm reading a tutorial and it has an example like this"
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> require 'rubygems'
> require 'RedCloth'
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> The tutorial says:
> "...the RubyGems library over-rides the require method and enables it =
to
> be used to
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> load gems as if they were normal, local libraries."
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> I don't know how it works.
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> Is there a rubygems require and an ordinary require?

The salient point is that require depends on your LOAD_PATH. There are =
many ways to inspect your load path, for example, you can start irb and =
look at the $: global variable. If you use require with a name like =
'string_extensions' it searches your load path for a matching file (it =
adds 'rb' or the appropriate extension file extension automatically). =
Basically, you can think of requiring 'rubygems' as adding all your =
installed gems to the load path so that they will be found if you =
require them.

Most developers (in my experience) discourage the use of explicitly =
requiring ruby gems in libraries. For a detailed explanation see: =
https://gist.github.com/54177

Whenever you require one of your files and it can't be found, it means =
that the file isn't in your current load path. For that reason, Ryan =
Davis above suggested you use ruby -I. (this explicitly adds your =
working directory to the load path) and Luke Gruber explained how you =
can use require with an absolute path.


> I'm using 1.9.2 and I know *require 'rubygems'* is not necessary as
> RubyGems is loaded
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> by default.  But I still don't understand the logic behind the
> "over-rides the require
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> method and enables it to be used to load gems as if they were normal,
> local libraries"
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> part.
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> 1.  Does RedCloth have the .rb suffix? Is it different from any simple
> library I can
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> make (e.g. string_extensions.rb) in that it has to use the rubygems
> version of
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> 'require'?
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> 2.  Regarding the 'string_extensions.rb' , is RubyGems even necessary?
> That is, does
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> the automatically-loaded RubyGems have any bearing on simple libraries
> that I may
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> create? Or is it just for downloaded gems like RedCloth?
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> Can someone please explain it to me in simple terms?
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> Thank you. =3D)
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> --=20
> Posted via http://www.ruby-forum.com/.
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