← Back to context

Comment by smilliken

6 days ago

They aren't talking about C and its descendants in particular, but more generally. For example in Haskell and Scheme there is only an if function and no if statement. And you're welcome to create an if function in any language you like and use it instead of the native syntax. I like to use an if function in PostgreSQL because it's less cumbersome than a case expression.

So in the abstract, if is a ternary function. I think the original comment was reflecting on how "if (true) ... " looks like a function call of one argument but that's obviously wrong.

4 comments

smilliken

Reply
disconcision  6 days ago

this is not quite right. haskell and scheme have if expressions, not if statements. that's not the same as if being a function. if is not, and cannot be, a function in scheme, as it does not have scheme function semantics. specifically, it is not strict, as it does not evaluate all its subexpressions before executing. since haskell is non-strict, if can be implemented as a function, and iirc it is

  • trealira  6 days ago

    > since haskell is non-strict, if can be implemented as a function, and iirc it is

    "If" can be implemented as a function in Haskell, but it's not a function. You can't pass it as a higher-order function and it uses the "then" and "else" keywords, too. But you could implement it as a function if you wanted:

      if' :: Bool -> a -> a
  if' True x _ = x
  if' False _ y = y

    Then instead of writing something like this:

      max x y = if x > y then x else y

    You'd write this:

      max x y = if' (x > y) x y

    But the "then" and "else" remove the need for parentheses around the expressions.

  • Zambyte  4 days ago

    if in Scheme can be, and in some cases is, implemented as a macro though. Which has arguments and can be called like a function.