[Haskell-cafe] education or experience?

[Rustom Mody]

On Mon, Dec 10, 2012 at 5:33 AM, Doug McIlroy <doug at cs.dartmouth.edu> wrote:

> > >   Matlab exploits them heavily (though represented as doubles).
>
> > Not sure what you are referring to
>
> I had in mind Matlab's frequent use of a Boolean array as
> a characteristic function describing some property of the
> elements of another array.  Such arrays are used to control
> other array operations. In this usage, the characteristic
> array may be optimized out of existense, but it fosters
> higher-level thinking and concise code.
>

In which case it goes back to APL's compress operator ie 1960.
http://www.aplusdev.org/APlusRefV2_8.html#HEADING179

Heres a session that demonstrates

     A+
     Copyright (c) 1990-2008 Morgan Stanley.  All rights reserved.
     This version is Release 4.22
     a ← 1 2 3 4 5
     b ← 1 0 1 1 0
     b/a
 1 3 4
     b ← 1 0 2 1 0
     b/a
 1 3 3 4



-- 
http://www.the-magus.in
http://blog.languager.org
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20121210/0bd106b2/attachment.htm>