> Quickscript’s purpose is to make it easy to extend DrRacket with small Racket scripts that can be used in the definition (or interaction) window, or to graphically interact with the user.

http://docs.racket-lang.org/quickscript/index.html

Cool. Scripts use the provided (define-script) construct, which has a lambda that takes the current selection and outputs the new content of that selection. Through keyword arguments it can get access to various other elements like the current frame, file, etc.

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