[bitc-dev] Change to type declarations
digitale at digitaleric.net
Mon Oct 18 12:26:41 EDT 2004
> I've been reading some papers, and I want to revise the way we are
> declaring types.
> In procedures, eliminate the type declarations in the formal parameters
> in favor of DECLARE forms:
> (defun fib (x)
> (declare (type int32 x))
> (+ (- x 1) (- x 2)))
(defun fib (x)
(declare (type uint32 x))
(if (> x 1)
(+ (fib (- x 1)) (fib (- x 2))
Although I understand reasoning about the recursion here may require a
bit more work. Fib may not be the best "hello world" program (the
example in the spec also gets this wrong BTW).
> and in expression context, THE forms:
> (let ((a (the int32 3))) ..body..)
> My intention is that these should always be permissible, but they should
> be largely optional, and that we will go to a type inferencing engine.
> HOWEVER, the type inference engine will operate by inserting these forms
> so that the types of all variables can be explicitly determined by the
> phase that builds the datatype.
> The motivator for this is that in level-1 BitC we want to introduce
> things like CONS, and to do so we will need parametric polymorphism.
parametric polymorphism: is this like "CONS<int32>" or like ML's "
type-t list" or something else entirely?
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