Equality of lambdas

[Alex Blewitt]

On 3 Jan 2010, at 23:04, Howard Lovatt <howard.lovatt at iee.org> wrote:

> Zdenek,
>
> For comparing lambdas
> you need to use equals not ==.

My experience in lambdas from other languages is that there's little  
point in supporting equality of lambdas other than identity. In the  
general case it's impossible to know whether two code segments will  
produce the same result - so comparing non-identical lambdas is  
somewhat futile. Even if you have a non-capturing lambda instance  
(like the identity function) then even if two are equal, what benefit  
does that give?Comparing lambdas of other types is unlikely to give  
the same result - and a good compiler should be able to optimise two  
lambdas in different locations but with the same AST to the same  
instance (preferably static if non-capturing). So that may introduce a  
level of visibillity into the workings of the compiler that may  
inhibit future optimisations.

On the other side of the coin - what is it that equality is supposed  
to assist with?

Sent from my (new) iPhone
>