From: Michael 'entropie' Trommer <mictro@...>
Date: 2006-01-03T04:56:47+09:00
Subject: Re: About blocks

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* dblack@wobblini.net (dblack@wobblini.net) wrote:
> Hi --
>=20
> On Mon, 2 Jan 2006, Surgeon wrote:
>=20
> >Hi,
> >
> >(This question might be answered previously. If so, I apologize.)
> >
> >Can we *ALWAYS* use plain methods instead of blocks? Yes, sometimes
> >using a block may be obviously better than using a method but I mean,
> >are there any situations in which the *ONLY* solution is to use a block
> >rather than a method? May someone be forced to use only and only a
> >block? I ask this because I am not very intelligent and I am not sure
> >that I will thoroughly understand the "block" concept.
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> You don't really use methods instead of blocks; you use methods --
> that is, you call methods -- with or without providing a code block
> for a given method call.
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> The block is part of the method call syntax, along with the method
> name and the argument list.  Whether or not it's mandatory is up to
> the method (as with arguments).  For example:
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>   def x
>   end
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>   def y
>     yield
>   end
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>   def z
>     yield if block_given?
>   end
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>   x                       # OK -- no block expected or given
>   x { puts "code block" } # block OK but ignored
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>   y                       # error, because no block to yield to
>   y { puts "code block" } # OK
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>   z                       # OK -- no yield will be attempted
>   z { puts "code block" } # also OK, and block will execute
>=20
>=20
> David

really intresting lecture!

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> --=20
> David A. Black
> dblack@wobblini.net
>=20
> "Ruby for Rails", from Manning Publications, coming April 2006!
> http://www.manning.com/books/black
>=20
So long
--
Michael 'entropie' Trommer;  http://ackro.org

ruby -e "0.upto((a=3D'njduspAhnbjm/dpn').size-1){|x| a[x]-=3D1}; p 'mailto:=
'+a"

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