[cltl3-devel] Types

[Marco Antoniotti]

On Sep 2, 2009, at 14:12 , Levente Mészáros wrote:

> Hi,
>
> Some issues about the type system that comes to my mind (some of them
> might be less important than the others):
> - no reliable way to figure out whether something is a type  
> specifier or not

Yep.  I use

(defun type-specifier-p (ts) (ignore-errors (subtypep ts t)))


> - no way to portably expand a type specifier by using its definition

Yep.

> - practically there is no reflection on types

Yep.


> - no easy way to specify a parametric type of strings with less than
> N characters (this is just an example of the issue: (deftype
> length-limited-string (limit) ...)
>   due to the limits of satisfies

Careful.  This opens up a can of worms.  There is no way to specify a  
recursive type either, but this would go really deep.

> - no portable way to get the inferred type of a function, a  
> variable, etc.

Environment access *could* mitigate this problem.

Cheers

Marco








>
> Cheers,
> levy
>
> -- 
> There's no perfectoin
>
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