Re: [stack] Cat Type Inference

This question implies the question "why would one want to statically verify
the types?". This one is fairly well-known: e.g. documentation, reducing
defects, and improving performance, so I'll assume that it is already known.
The question that remains then is "why allow the compiler (or better yet,
the editor) infer the types instead of insisting the programmer write them
out?".

If you want static type verification then you will encounter a fair number
of scenarios where expressing the types is non-trivial and the type
signature may even be longer than the function body. Sometimes the type is
not easily deduced by a programmer due to lack of familiarity with the
complexities of type systems, but the programmer still knows how to write
the program they want correctly. Finally, there are scenarios where the type
is so trivially obvious, writing it is redundant.

As for whether or not it is obvious, that really depends on your experience
with statically typed languages, and an understanding of how the refactoring
capabilities of modern IDEs for C# and Java actually do their magic. The
more type inference you are able to do with a langauge, the more an IDE can
refactor your code for you.

Hope this helps.

Christopher Diggins


On 4/16/07, chris glur <[email protected]> wrote:
>
>   A perhaps trivial question [which also serves to test if my - via
> gmail - posts get through] is: "is it obvious why one would
> want to 'infer the types' ?"
>
> == Chris Glur.
>
> On 4/11/07, Christopher Diggins <[email protected] <cdiggins%40gmail.com>>
> wrote:
> > I've written a short article explaining how to infer the types using
> > the example of a non-trivial higher order function: "[] eval eval" at
> > http://cdiggins.com/2007/04/11/type-inference-example-in-cat/ for
> > those interested in a more down to earth explanation of the type
> > inference algorithm.
> >
> > Cheers,
> > Christopher Diggins
> > http://www.cdiggins.com
> >
>
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