Geiser features 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).