using less stack

[Graham Hutton]

> In the case of foldr the end of the list has to be
> reached before anything can be evaluated. 

This is perhaps a good time to point out the common missconception that
foldr can only be used to define functions that process the elements of
lists in right-to-left order.  For a discussion of this point, see section
5 of my JFP tutorial paper on foldr, which (amonst other things) shows
how to sum a list of numbers in left-to-right order using foldr:

   http://www.cs.nott.ac.uk/~gmh/fold.pdf

Graham

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| Dr Graham Hutton                     Email : gmh@cs.nott.ac.uk             |
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