On Thu, Jul 16, 2009 at 5:04 PM, Lukas Renggli<reng...@gmail.com> wrote:
> ((aCollection readStream
> select: [ :e | ... ])
> collect: [ :e | ... ])
> contents
>
> will iterate only once. Furthermore the second approach allows any
> combination of any of the enumeration methods, not just a few
> predefined ones. Also the implementation is less error prone, because
> it just uses the standard methods on collection and stream.
This is what I did in Nile:
NSCollectionStream>>select: aBlock
"Returns a new stream which contains a selection of elements in the
receiver. All elements of the receiver are passed to aBlock. This is
really like Collection>>select:."
^ NSSelectStream selectBlock: aBlock inputStream: self
NSSelectStream being a kind of stream whose #next method iterate on
the input stream:
NSSelectStream>>next
self inputStream do: [:each | (selectBlock value: each) ifTrue:
[^ each]].
--
Damien Cassou
http://damiencassou.seasidehosting.st
"Lambdas are relegated to relative obscurity until Java makes them
popular by not having them." James Iry
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