Specifications of 'any', 'all', 'findIndices'

[Koen Claessen]

Eric Shade wondered:

 | I have some questions about the specifications of
 | 'any', 'all', and 'findIndices' in the Haskell 98
 | reports.  [...] it seems to me that it generates a lot
 | of garbage because map will produce a list of Booleans
 | [...]

Several people have already commented on this. What I want
to add is the following.

The definitions in the Haskell report are a *specification*,
not an implementation. It probably depends on the compiler
which particular implementation runs faster.

Therefore, the Haskell report provides a clear (yes, this is
debatable) *possible* implementation, and the compiler
writer is free to implement this in whatever way (s)he
likes. As long as the implementation has the same functional
behavior as the specification in the report.

/Koen.

--
Koen Claessen         http://www.cs.chalmers.se/~koen
phone:+46-31-772 5424      mailto:koen@cs.chalmers.se
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Chalmers University of Technology, Gothenburg, Sweden