Clean 2.0 dynamics

Simon Peyton-Jones
Wed, 9 Jan 2002 01:43:52 -0800

I think that "proper" dynamics are one of those things that
are easier said than done.  Yes, GHC has more of the
infrastructure now than it used to have.  But I don't think
it's a routine matter to come up with a robust design, or
to implement that design.  But it would certainly be a=20
good and useful project. =20

We don't have any plans here to work on it, though.


| -----Original Message-----
| From: Krasimir Angelov []=20
| Sent: 09 January 2002 09:00
| To:
| Subject: Clean 2.0 dynamics
|     Hi
| Are you known about new Clean 2.0 compiler and your
| new features. There is two general extensions in
| language: Dinamics and their automatic loading\writing
| to files or streams. Clean Dinamics are most similar
| to corresponding Haskell Dinamic type. Main difference
| is in some language extensions which allow dynamic
| types to be dynamicaly unified. See following Clean
| function:
| dynApply :: Dynamic Dynamic -> Dynamic
| dynApply (f :: a -> b) (x :: a) =3D dynamic (f x :: b)
| dynApply df dx =3D dynamic ("cannot apply",df,"to",dx)
| In Haskell the only way to define dynApply is with
| using of unsafeCoerce# which is type unsafe. Runtime
| type unification is useful but not obligatory. I think
| that most important thing is automatic loading\writing
| of Dynamics. Loading/writing facilities in Clean needs
| dynamic linker which can dynamical loading of object
| files. As I known in GHC-5.02 we already have such
| linker which is part of runtime system. I think that
| is'n too difficult to implement this feature in GHC.
| Is there any plan to implement this. For functional
| programing Dynamics can be same as COM/Corba for OO
| programing. While runtime type unification needs some
| syntax extensions (As I known using polymorphic types
| in pattern type signatures are always implemented
| according to rank-N types), dynamic linking needs only
| backend changes.
| Krasimir
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