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> "for" needs to be implemented as a special form as it emits some optimizations that are only available at the Core Erlang level. That's interesting. I wonder
by randomstudent 9y ago
> "for" needs to be implemented as a special form as it emits some optimizations that are only available at the Core Erlang level.
That's interesting. I wonder if a future Elixir version could have a way of defining macros which sould emit these optimizations. Is this a likely direction for future developments?
> "with" needs to be implemented as a special form as it has different lexical properties than a bunch of nested cases.
Could you expand on this a little? What are those different lexical properties?
- josevalim 9y ago> That's interesting. I wonder if a future Elixir version could have a way of defining macros which sould emit these optimizations. Is this a likely direction for future developments? To do so, we would need to compile to core, and that means tools like Cover and the Erlang debugger would no longer work with Elixir. It is unlikely we will go to this direction. > Could you expand on this a little? What are those different lexical properties? If you compile a "with" to a bunch of cases, a variable from the outer case would be available to both success and failure cases. Take this code: a = true with true <- a = false do a else _ -> a end In Elixir it returns true because `a = false` has no impact on else. But if it compiled to a bunch of cases, we would get: a = true case a = false do true -> a _ -> a end And that returns false.