[Haskell-cafe] Are constructors strict?

[Daryoush Mehrtash]

I am having hard time understanding the following paragraph in "Purely
functional Lazy non-deterministic  programing" paper
http://www.cs.rutgers.edu/~ccshan/rational/lazy-nondet.pdf

The problem with the naive monadic encoding of non-determinism is that the
arguments to a constructor must be deterministic. If these arguments are
themselves results of non-deterministic computations, these computations
must be performed completely before we can apply the constructor to build a
non-deterministic result.



Why does the argument to constructors must be deterministic?    WHy is it
that thunks are not used in this case?


Thanks

-- 
Daryoush

Weblog:  http://onfp.blogspot.com/
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