[racket] Ceylon language borrows Typed Racket features?

From: Luke Vilnis (lvilnis at gmail.com)
Date: Mon Nov 14 23:18:20 EST 2011

Has anyone taken a look at the upcoming language
It feels to me like a pretty aggressively blub-y Java clone, but it has two
features that seem like they're ripped straight out of Typed Racket.

It looks like the language includes a basically verbatim copy of TR's
dotted type parameters, which it calls "sequenced type
For example, the supertype of all tuples is written

It also has untagged union
Int|Bool) which can be deconstructed with switch-case statements, sort of
like a watered down version of occurence typing:

switch (foo)
case (is Bool) {
    // this type checks
    local isTrue = foo || true;
case (is Int) {
    // so does this!
    local x = foo + 1;

Anyhow, I just thought it was interesting that a language positioning
itself as the successor to Java has as its main point of difference two
features that are almost identical to those in Typed Racket - type-safe
untagged unions and non-uniform variable-arity polymorphism. Even though
the actual language is pretty unappealing to me (and I suspect it might be
to most people who frequent this mailing list) I thought this was a neat
confirmation of the broad appeal of TR's ideas.
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