Re: [stack] Cat Type Inference

On 4/16/07, William Tanksley, Jr <[email protected]> wrote:
>
> Christopher Diggins <[email protected]> wrote:
> > 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?".
>
> Your answer was better than mine, but I did have one little tidbit I
> think it worthy: a program that must be type-inferenced must be
> written in a predictable manner: the compiler has to be able to figure
> it out easily. This makes it generally easier to analyze even for
> humans.

When you say "predictable" I am assuming you are referring programs
with straightforward or simple types, and not to the set of well-typed
programs in general.

Well I agree it would be ideal for programs to be written in a
predictable manner, I don't believe it to be a theoretical
prerequisite. I know that other type inferring compilers (e.g.
Haskell) are quite limited with regards to what they can infer but it
is mostly a combination of intention (i.e. the designers wanted a
stricter type systems than I see as being practical) and
implementation approach.

It'll remain to be seen how sophisticated the Cat inference engine
turns out to be in practice once the current version is completed. I
am confident however (based on the performance of the earlier
prototype) that Cat will be able to handle inferring the type of
complex edge-case programs with ease. This is due mainly because of
the simplicity of the type system of Cat compared to other languages.

Cheers,
Christopher