I’ve had the 2htdp-typed package
<https://github.com/lexi-lambda/racket-2htdp-typed> available for a little
while now, which is a Typed Racket wrapper for the HtDP/2e teachpacks. It was
missing big-bang, since it is implemented as a macro, but I have now added
support for big-bang in Typed Racket.
The syntax of big-bang is identical to its untyped equivalent except for one
thing: it requires an annotation that specifies what the type of the WorldState
parameter should be. The exact syntax for big-bang is provided in the
documentation.
There are still a couple of unsupported features:
The universe/networked worlds (“The World is Not Enough”) are not supported.
This actually shouldn’t be terribly difficult to add, I just have absolutely no
experience working with universe programs, so I haven’t tried.
The 2htdp/planetcute collection of sprites is not yet available in Typed
Racket. This also shouldn’t be terribly difficult to add, but my first attempt
ran into some complexities in how the identifiers are provided that I did not
anticipate, and I haven’t taken the time to look into it since. (See
https://github.com/racket/htdp/issues/2
<https://github.com/racket/htdp/issues/2> for some limited information about
that.)
Otherwise, I think everything should work just fine. I don’t have many programs
that use these libraries sitting around, but I’d love to know if this wrapper
works with existing world/universe programs.
Feedback and bug reports much appreciated, pull requests welcome!
Alexis King
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