What's the best way to name a predicate function?

Question

I'm looking at a function called:

WhetherAddFloor(leg) -> bool

and when I see code like:

if(WhetherAddFloor(l)) ...

it smells odd and am wonder if something like:

CheckAddFloorNeeded(leg) -> bool

wouldn't be better? Thoughts?

Answer 1

In languages where question marks are allowed in function names the style is to append one to the end if the function returns boolean:

FloorNeeded?(leg)

But where that isn't syntactically possible the convention is to use the word 'is' at the beginning:

isFloorNeeded(leg)

It's generally easy to read and understand and it seems like it'll fit your situation.

Answer 2

WhetherAddFloor() sounds as quite an unfortunate choice to me.

CheckAddFloorNeeded() is better, if the function has a substantial amount of work to do, and you would like to advertise that fact to those who use the interface.

IsFloorNeeded() is also good, if the function does not have a substantial amount of work to do, (say, it is just an accessor to a previously computed member,) or if you want to keep this little bit of information secret from those using the interface.