-*- mode: org -*-
Overview
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).
- Support for inline images in schemes, such as Racket, that treat them as first order values.
NOTE: if you’re not in a hurry, Geiser’s website (http://www.nongnu.org/geiser/) contains a nicer manual, also included in Geiser tarballs as a texinfo file (doc/geiser.info).
Requirements
Geiser needs Emacs 23.2 or better, and at least one of the supported scheme implementations:
- Guile 2.0 or better.
- PLT Racket 6.0 or better.
- Chicken 4.8.0 or better.
- MIT/GNU Scheme 9.1.1 or better.
- Chibi 0.7.3 or better.
- Chez 9.4 or better.
Installation
The easiest way is to use MELPA, and just type `M-x install-package RET geiser` inside emacs.
Geiser can be used either directly from its uninstalled source tree or byte-compiled and installed after performing the standard configure/make/make install dance. See the INSTALL file for more details.
Chicken Addendum
These steps are necessary to fully support Chicken Scheme, but are not required for any other scheme.
- Install the necessary support eggs: $ chicken-install -s apropos chicken-doc
- Update the Chicken documentation database: $ cd `csi -p ‘(chicken-home)’` $ curl http://3e8.org/pub/chicken-doc/chicken-doc-repo.tgz | sudo tar zx
Basic configuration
The loading invocations above install all supported Scheme implementations. You can list explicitly the ones that you want by setting the variable `geiser-active-implementations’ before loading geiser.el. For instance:
(setq geiser-active-implementations ‘(chicken guile))
On opening a scheme file, Geiser will try to guess its Scheme, defaulting to the first in the list. Use `C-c C-s’ to select the implementation by hand (on a per file basis).
Check the geiser customization group for some options with:
M-x customize-group RET geiser RET
In particular, customize `geiser-<impl>-binary’, which should point to an executable in your path.
To start a REPL, M-x geiser.
Completion with company-mode
Geiser offers identifier and module name completion, bound to M-TAB and M-` respectively. Only names visible in the current module are offered.
While that is cool and all, things are even better: if you have company-mode (http://company-mode.github.io/) installed, Geiser’s completion will use it. Just require company-mode and, from then on, any new scheme buffer or REPL will use it.
Quick key reference
In Scheme buffers:
| C-c C-z | Switch to REPL |
| C-c C-a | Switch to REPL and current module |
| C-c C-s | Specify Scheme implementation for buffer |
|---|---|
| M-. | Go to definition of identifier at point |
| M-, | Go back to where M-. was last invoked |
| C-c C-e m | Ask for a module and open its file |
| C-c C-e C-l | Add a given directory to Scheme’s load path |
| C-c C-e [ | Toggle between () and [] for current form |
| C-M-x | Eval definition around point |
| C-c C-c | Eval definition around point |
| C-c M-e | Eval definition around point and switch to REPL |
| C-x C-e | Eval sexp before point |
| C-c C-r | Eval region |
| C-c M-r | Eval region and switch to REPL |
| C-c C-b | Eval buffer |
| C-c M-b | Eval buffer and switch to REPL |
| C-c C-m x | Macro-expand definition around point |
| C-c C-m e | Macro-expand sexp before point |
| C-c C-m r | Macro-expand region |
| C-c C-k | Compile and load current file |
| C-c C-l | Load scheme file |
| C-c C-d d | See documentation for identifier at point |
| C-c C-d s | See short documentation for identifier at point |
| C-c C-d i | Look up manual for identifier at point |
| C-c C-d m | See a list of a module’s exported identifiers |
| C-c C-d a | Toggle autodoc mode |
| C-c < | Show callers of procedure at point |
| C-c > | Show callees of procedure at point |
| M-TAB | Complete identifier at point |
| M-`, C-. | Complete module name at point |
| TAB | Complete identifier at point or indent |
| (If `geiser-mode-smart-tab-p’ is t) |
In the REPL
| C-c C-z | Start Scheme REPL, or jump to previous buffer |
| C-c M-o | Clear scheme output |
| C-c C-q | Kill Scheme process |
| C-c C-l | Load scheme file |
| C-c C-k | Nuke REPL: use it if the REPL becomes unresponsive |
|---|---|
| M-. | Edit identifier at point |
| TAB, M-TAB | Complete identifier at point |
| M-`, C-. | Complete module name at point |
| M-p, M-n | Prompt history, matching current prefix |
| C-c C-m | Set current module |
| C-c C-i | Import module into current namespace |
| C-c C-r | Add a given directory to scheme’s load path |
| C-c C-d C-d | See documentation for symbol at point |
| C-c C-d C-m | See documentation for module |
| C-c C-d C-a | Toggle autodoc mode |
In the documentation browser:
| f | Next page |
| b | Previous page |
|---|---|
| TAB, n | Next link |
| S-TAB, p | Previous link |
| N | Next section |
| P | Previous section |
| k | Kill current page and go to previous or next |
| g, r | Refresh page |
| c | Clear browsing history |
| ., M-. | Edit identifier at point |
| z | Switch to REPL |
| q | Bury buffer |
In backtrace (evaluation/compile result) buffers:
- M-g n, M-g p, C-x ` for error navigation.
- q to bury buffer.