[racket] #<undefined> and backward compatibility

From: Neil Toronto (neil.toronto at gmail.com)
Date: Fri Apr 18 10:48:51 EDT 2014

On 04/18/2014 07:54 AM, Matthew Flatt wrote:
> No one expects the #<undefined> value!

Is this a... subtle... reference? [1]

> Based on our experiment so far, it looks like the drawbacks probably
> outweigh the benefits...

I think you meant this the other way around. :)

Another benefit is that Typed Racket will no longer have to consider 
non-function letrec bindings as having the type (U Undefined A) where A 
is the "real" type. (Technically, (U Undefined A) *was* the real type.)

Neil ⊥

[1] No one expects the Spanish Inquisition!

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