From: jbw <jbw@...>
Date: 2010-03-31T00:46:59+09:00
Subject: Re: require and include??

On Tue, Mar 30, 2010 at 4:05 PM, rantingrick <rantingrick@gmail.com> wrote:
> Hello,
>
> I am having trouble understanding the difference between require and
> include. Also i need to know how to import a certain function or class
> into my current namespace.

http://ruby-doc.org/docs/ProgrammingRuby/html/tut_modules.html
This might clear things up, but to summarise  include adds methods,
require adds modules.


> Now before i go any further i should explain that i am a Python
> programmer and i understand that whilst Ruby and Python share some
> similarities there are major differences between the languages,  and
> that is what seems to have me stumped here.
>
> In python we use the "import" statement to bring modules,  functions,
> whatever. And the import statement can function in many ways,
> observe...
>
> if i want to bring all the names from the math module into my current
> namespace without the need to qualify the names i can say...(note:
> dir() shows the current namespace!)
>>>> dir()
> ['__builtins__', '__doc__', '__name__', '__package__']
>>>> from math import *
>>>> dir()
> ['__builtins__', '__doc__', '__name__', '__package__', 'acos',
> 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'ceil',
> 'copysign', 'cos', 'cosh', 'degrees', 'e', 'exp', 'fabs', 'factorial',
> 'floor', 'fmod', 'frexp', 'fsum', 'hypot', 'isinf', 'isnan', 'ldexp',
> 'log', 'log10', 'log1p', 'modf', 'pi', 'pow', 'radians', 'sin',
> 'sinh', 'sqrt', 'tan', 'tanh', 'trunc']
>>>> hypot(3,4)
> 5.0
>
> Now if i want to just use a certain function, class, constant, i can
> call for just those specific names like...

Not sure there is a clean way to do this.

>>>> dir()
> ['__builtins__', '__doc__', '__name__', '__package__']
>>>> from math import hypot, pi
>>>> dir()
> ['__builtins__', '__doc__', '__name__', '__package__', 'hypot', 'pi']
>>>> pi
> 3.1415926535897931
>>>> hypot(3,4)
> 5.0
>>>>
>
> Now if i want to bring a reference to the module in and then qualify
> every thing within the module by perpending the
> "module_name.identifier" i can say...
>
>>>> import math
>>>> dir()
> ['__builtins__', '__doc__', '__name__', '__package__', 'math']
>>>> math.hypot(3,4)
> 5.0
>
> Ok, i know Ruby is different, so tell me how i do the same thing only
> in Ruby terms. Specifically i need to bring in a function that resides
> in a module in a different file. How do i do this?
>
>