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17.4 Interactive Module Loading

The bindings documented in this section are provided by the racket/enter and racket/init libraries, which means that they are available when the Racket executable is started with no command-line arguments. They are not provided by racket/base or racket.

(enter! module-path)
(enter! #f)
(enter! module-path flag ...+)
flag = #:quiet
  | #:verbose-reload
  | #:verbose
  | #:dont-re-require-enter
Intended for use in a REPL, such as when racket is started in interactive mode. When a module-path is provided (in the same sense as for require), the corresponding module is loaded or invoked, and the current namespace is changed to the body of the module via module->namespace. When #f is provided, then the current namespace is restored to the original one.

If invoking module-path requires loading any files, then modification dates of the files are recorded. If the file is modified, then a later enter! re-loads the module from source; see also Module Re-declarations. Similarly if a later enter! transitively requires a modified module, then the required module is re-loaded. Re-loading support works only for modules that are first loaded (either directly or indirectly through transitive requires) via enter!.

Additional flags can customize aspects of enter!:
  • When enter! loads or re-loads a module from a file, it can print a message to (current-error-port). Use the #:verbose flag to print a message about such loads and re-loads, #:verbose-reload to print a message only for re-loaded modules, and #:quiet for no printouts. The default reporting corresponds to #:verbose-reload.

  • After switching namespaces to the designated module, enter! automatically requires racket/enter into the namespace, so that enter! can be used to switch namespaces again. In some cases, requiring racket/enter might not be desirable (e.g., in a tool that uses racket/enter); use the #:dont-re-require-enter flag to disable the require.