* 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 9.2 or better

* Installation

  The easiest way is to use ELPA/Marmalade, 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 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-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-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.