[tomxor]

Yes I use arrow functions all the time but I was under the impression expressions must be strictly closed to be true lambdas? although to be honest i can't find any definitive info on this, so now I suspect my definition might be too strict...

I find it very useful to know that all variables in the expression are bound, expressions with free variable can be more complex to reason about, which is fine, but it would be nice to be able to easily differentiate without having to carefully parse each expression first - so a separate syntax just for that purpose would be nice - I thought that's what true lambda functions were (disallowing free variables), but it looks like i'm wrong, i guess that feature doesn't exist.