determining if a int is a power
paul.hudak at yale.edu
Sat Nov 8 07:13:06 EST 2003
But note that x `seq` x is equivalent to x, even operationally. To see
why denotationally, note that if x evaluates to _|_, so does x `seq` x.
And if x evaluates to a value v, so does x `seq` x. To see why
operationally, consider the two lists:
let x = 1+1 in [x `seq` x]
let x = 1+1 in [x]
Using conventional lazy evaluation in both cases, the term "1+1" is not
evaluated until the head of the list is taken. In other words, x `seq`
x in no way hurries the evaluation of x.
Wolfgang Jeltsch wrote:
> Am Samstag, 8. November 2003, 00:22 schrieb Hamilton Richards:
>>Also note that
>> if x then True else False
>>is just a verbose way of writing
> Actually, it's just a verbose way of writing x `seq` x, but this detail is, of
> course, not interesting for beginners.
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