[racket] How to read procedure documentation?

From: Neil Van Dyke (neil at neilvandyke.org)
Date: Fri Apr 19 15:00:29 EDT 2013

Manfred Lotz wrote at 04/19/2013 02:18 PM:
>  From this I'm wondering why there are predicates when for example I
> would expect strings?

The language you're seeing is mostly that of Racket *contracts*, even 
though the implementation might not be using the Racket contract 
software mechanism: 

It is not the prettiest or fastest way to communicate a synopsis for a 
bit of API, but you can quickly learn how to read it slowly.

Neil V.

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