[plt-scheme] Type for Hash Tables

From: Sam TH (samth at ccs.neu.edu)
Date: Thu Mar 12 08:35:21 EDT 2009

On Wed, Mar 11, 2009 at 10:51 AM, Paulo J. Matos <pocmatos at gmail.com> wrote:
> Hi,
> There doesn't seem to be any type for hash tables, how can I type a
> function that receives or returns an hash table?

There is a type for hash tables, but it seems to be missing from the docs.

It's used like this:

(: lookup-foo ((HashTable Symbol Number) -> Number))
(define (lookup-foo h) (hash-ref h 'foo))

I'll fix the docs momentarily.
sam th
samth at ccs.neu.edu

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