Simplify if x then y else y to y?

[dhall-lang]

Simplify if x then y else y to y?

[Gabriella439]

Yeah, that seems reasonable to me. Would you like to open a pull request to update the semantics?

Note that because this is comparing expressions for equality you have to explicitly specify the equivalence relation like this:

l ⇥ x₀   r ⇥ x₁   x₀ ≡ x₁
──────────────────────── 
if t₀ then l else r ⇥ x₀

It's probably also worth doing the same for other boolean operators, such as x && x = x and x == x = True

[ocharles]

Sure, I can do that. Can you assign this one to me as well? I'm hoping to find some time to do some hobby hacking tonight.