Porting Untyped Modules to Typed Racket

Sam Tobin-Hochstadt <samth@ccs.neu.edu>

To adapt a library to Typed Racket, the following steps are required:

• Determine the data manipulated by the library, and how it will be represented in Typed Racket.

• Specify that data in Typed Racket, using require/typed and opaque and struct.

• Use the data types to require the various functions and constants of the library.

• Provide all the relevant identifiers from your new adapter module.

For example, here’s a module for adapting the racket/bool library:

#lang typed/racket

(require/typed racket/bool

[true Boolean]

[false Boolean]

[symbol=? (Symbol Symbol -> Boolean)]

[boolean=? (Boolean Boolean -> Boolean)]

[false? (Any -> Boolean)])

(provide true false symbol=? boolean=? false?)

More substantial examples are available in the typed collection. In particular, see the various files in typed/net, such as typed/net/url.ss.