Geiser is a generic Emacs/Scheme interaction mode, featuring an enhanced REPL and a set of minor modes improving Emacs' basic scheme major mode. The main functionalities provided are:

• Evaluation of forms in the namespace of the current module.
• Macro expansion.
• File/module loading.
• Namespace-aware identifier completion (including local bindings, names visible in the current module, and module names).
• Autodoc: the echo area shows information about the signature of the procedure/macro around point automatically.
• Jump to definition of identifier at point.
• Access to documentation (including docstrings when the implementation provides it).
• Listings of identifiers exported by a given module.
• Listings of callers/callees of procedures.
• Rudimentary support for debugging (list of evaluation/compilation error in an Emacs' compilation-mode buffer).

Currently supported implementations are Guile and PLT.

• Guile 1.9.x (git master until 2.0 is released)
• Racket 5.0.1 or better required.