Thank you both.
Does that resolve the question? Yes.
I'll update the comments so it is more obvious what is going on. Janek Dnia czwartek, 17 października 2013, Simon Peyton-Jones napisał:
Yes, a join point should always have at least one argument, although it can be a zero-width argument that takes no registers to pass. (That's the State# RealWorld thing Simon mentions.)
See Note [Join point abstraction] in Simplify.lhs.
At one point the demand analyser was noticing that the argument was unused, and removing it, but I believe I fixed that.
Does that resolve the question? Are any comments in the code inconsistent?
Please clarify with Note [blah], and/or cross-reference to other Notes.
Simon
| -----Original Message----- | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Simon | Marlow | Sent: 17 October 2013 09:44 | To: Jan Stolarek; ghc-devs@haskell.org | Subject: Re: Non-escaping lets, join-points and binding updatability | | On 16/10/2013 18:27, Jan Stolarek wrote: | > Hi all, | > | > I'm trying to understand this: | > | > 1. Note [What is a non-escaping let] says that one of conditions of | | binding being a non-escaping | | > let is non-updatability. | > 2. My understanding is that a if a binding has at least one parameter | | it is non-updatable, though | | > I suspect that converse does not have to be true (lambdas) | > 3. Join-points are implemented using LNE bindings and I can imagine a | | join-points not having any | | > parameters (and not being a lambda). | | A join-point always has at least one argument. If there are no | arguments, then a dummy one of type State# RealWorld is added, to avoid | creating a thunk. | | Cheers, | Simon | _______________________________________________ | ghc-devs mailing list | ghc-devs@haskell.org | http://www.haskell.org/mailman/listinfo/ghc-devs