ok we are in sync. Stef On Jul 13, 2010, at 4:21 PM, Marcus Denker wrote:
On Jul 13, 2010, at 3:56 PM, Stéphane Ducasse wrote:
Strange this is not what gilad mentioned. A pluggable type system: you can plug multiples one and the runtime is not influenced by type systems.
Yes.
Gradual Typing is *not* about multiple type systems. It's just *one* Type System. Which has the nice property of dealing nicely with code in the case of having no type annotations.
One can implement Gradual Typing without any Pluggable Types. Then it's the only type-system the language has. Type-check would in this case not be optional. It would be always done, but without annotations leading to no static checking done. But it could actually influence the language semantics (e.g. one could imagine a language that compiles in dynamic checks following the gradual type checker in the case of no annotation. Instead of a runtime that has the checks build in like smalltalk).
In turn, one could provide a Type-System based on Gradual Typing *on top* of a Pluggable Types infrastrustructure.This then would be a type-system that is optional, not influencing language semantics.
So both are orthogonal. But of course related. (how to type-check dynamic systems without making them static).
Marcus
-- Marcus Denker -- http://www.marcusdenker.de INRIA Lille -- Nord Europe. Team RMoD.
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