[racket] Constructors for sequences

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Mon Apr 30 09:56:17 EDT 2012

On Apr 30, 2012, at 8:23 AM, Sam Tobin-Hochstadt wrote:

>> Another problem is that not all sequence types are polymorphic. For example,
>> strings are sequences, but strings can contain only characters. So what
>> would
>>  (sequence-map char->integer "abc")
>> return? Custom sequence types can add arbitrary additional constraints.
> I believe that the Scala folks have handled this too.  I really
> recommend looking a what they've done.

Ryan: I am not saying that I want polymorphism in the elements of the sequence. I am calling for polymorphism in the constructor. 

Sam: since this issue appears to be particularly relevant in the context of Typed Racket, I think you should take ownership of the issue. I am sure there is a paper in this topic, single-authored or lead-authored, for you. 

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