[racket-dev] Lists aren't sets, but have set-like operations

From: J. Ian Johnson (ianj at ccs.neu.edu)
Date: Mon Aug 26 20:52:06 EDT 2013

I like this, except now the hash sets have too little exposed. There isn't a special sequence-syntax that I can get a hold of for faster iteration when I know the type of data I'm working with.
----- Original Message -----
From: "Matthias Felleisen" <matthias at ccs.neu.edu>
To: "Carl Eastlund" <cce at ccs.neu.edu>
Cc: "J. Ian Johnson" <ianj at ccs.neu.edu>, "Racket Developers" <dev at racket-lang.org>
Sent: Thursday, August 22, 2013 2:47:44 PM GMT -05:00 US/Canada Eastern
Subject: Re: [racket-dev] Lists aren't sets, but have set-like operations

On Aug 22, 2013, at 2:31 PM, Carl Eastlund wrote: 

Here's what I propose to do now: 

- rename set? to generic-set?; this predicate recognizes the new all-inclusive generic set type 

- rename set-immutable? to set?; this predicate recognizes the pre-existing immutable hash set type 

- leave set-mutable? and set-weak? alone; they recognize the other two hash set types (on the mutability axis) 

- allow multiple-set operations to combine equal-based hash sets and lists, since both use equal? for equality 

Sounds like the right direction to me. -- Matthias 

Posted on the dev mailing list.