2.1 Language Declared in Source

The The Racket Language mode in DrRacket is a kind of meta-language, where the program itself specifies its language, usually through a #lang line.

More generally, when using this mode, the definitions window must contain a module in some form. Besides #lang, a Racket module can be written as (module ...); aside from comments, the definitions window must contain exactly one module.

In the details pane of the language dialog, some of the configuration options correspond to using various libraries and thus can be used without DrRacket. Here’s how, for the ones that are straightforward (the ones not mentioned here require more sophisticated configuration of various libraries).