On 7/27/06, Dan Doel wrote:

On 7/26/06, Donn Cave wrote:

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That looks to me like a different way to spell if then else, but maybe that's the answer to the question - conceptually, for every "then" there really is an "else", however you spell it, and only in a procedural language does it make any sense to leave it implicit. The exception that proves the rule is "else return ()" -, e.g.,

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Strictly speaking that generalizes to any functional context where a generic value can be assigned to the else clause, but there don't tend to be that many other such contexts. Does that answer the question?

I believe his question was why if-then-else is syntax, rather than the function he gave. Since haskell is non-strict, it doesn't need to be implemented as syntax (unlike, say, scheme, where it needs to be a special form/macro to avoid executing both branches).

I imagine the answer is that having the syntax for it looks nicer/is clearer. "if a b c" could be more cryptic than "if a then b else c" for some values of a, b and c.

Also, you get less parenthesis: myAbs x = if x < 0 then negate x else x /S -- Sebastian Sylvan +46(0)736-818655 UIN: 44640862