* 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).

   NOTE: if you're not in a hurry, [[http://www.nongnu.org/geiser/][Geiser's website]] contains a nicer
   manual, also included in Geiser tarballs as a texinfo file
   (doc/geiser.info).

* Supported scheme implementations

    - Guile 2.0 (not released yet: use the latest git master branch).
    - PLT Racket 5.0.1 or better.

* Installation
  Geiser can be used either directly from its uninstalled source tree
  or byte-compiled and installed after perfoming the standard
  configure/make/make install dance.

*** In place
    - Extract the tarball or clone the git repository anywhere in your
      file system. Let's call that place <path-to-geiser>.
    - In your .emacs:

      #+BEGIN_SRC emacs-lisp
      (load-file "<path-to-geiser>/elisp/geiser.el")
      #+END_SRC

*** Byte-compiled
    - Create a build directory, `build', say:
      #+BEGIN_SRC shell
      $ cd <path-to-geiser>
      $ mkdir build; cd build
      #+END_SRC
    - Configure and make:
      #+BEGIN_SRC shell
      $ ../configure && make
      #+END_SRC

    Now, you can use the byte-compiled Geiser in place by adding to
    your .emacs:

    #+BEGIN_SRC emacs-lisp
    (load "<path-to-geiser>/build/elisp/geiser-load")
    #+END_SRC

    or, alternatively, install it with:

    #+BEGIN_SRC shell
    $ make install
    #+END_SRC

    (you might need to get root access, depending on your installation
    directory) and, instead of the above load forms, require
    'geiser-install (not 'geiser, mind you) in your emacs
    initialization file:

    #+BEGIN_SRC emacs-lisp
    (require 'geiser-install)
    #+END_SRC

    You're ready to go!

* 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-impl-installed-implementations' *before*
  loading geiser.el. For instance:

    #+BEGIN_SRC emacs-lisp
    (setq geiser-impl-installed-implementations '(racket guile))
    #+END_SRC

   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
    [[http://nschum.de/src/emacs/company-mode/][company-mode]] installed, Geiser's completion will use it. Just
    require company-mode and, from then on, any new scheme buffer or
    REPL will use it. If you didn't know about Nikolaj Schumacher's
    awesome mode, check [[http://www.screentoaster.com/watch/stU0lSRERIR1pYRFVdXVlRVFFV/company_mode_for_gnu_emacs][this screencast]].

* Quick key reference

*** In Scheme buffers:

    |---------------------+-------------------------------------------------|
    | C-c C-z             | Switch to REPL                                  |
    |---------------------+-------------------------------------------------|
    | C-u C-c C-z         | 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-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-m x           | Macro-expand definition around point            |
    |---------------------+-------------------------------------------------|
    | C-c C-m e           | Macro-expand sexp before point                  |
    |---------------------+-------------------------------------------------|
    | C-c C-m r           | Marcro-expand region                            |
    |---------------------+-------------------------------------------------|
    | C-u C-c C-m [x,e,r] | (With prefix, macro expansions are recursive)   |
    |---------------------+-------------------------------------------------|
    | C-c C-k             | Compile and load current file                   |
    |---------------------+-------------------------------------------------|
    | C-c C-l             | Load current file                               |
    |---------------------+-------------------------------------------------|
    | C-c C-d d           | See documentation 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              |
    |---------------------+-------------------------------------------------|
    | C-c C-x f           | See a generic's methods signatures              |
    |---------------------+-------------------------------------------------|
    | 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 C-q     | Kill Scheme process                                |
    |-------------+----------------------------------------------------|
    | 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-k     | Nuke REPL: use it if the REPL becomes unresponsive |
    |-------------+----------------------------------------------------|
    | C-c C-m     | Set current module                                 |
    |-------------+----------------------------------------------------|
    | C-c C-i     | Import module into current namespace               |
    |-------------+----------------------------------------------------|
    | C-c C-l     | Load scheme file                                   |
    |-------------+----------------------------------------------------|
    | 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:

    |------------+----------------------------------------------|
    | n, f       | Next page                                    |
    |------------+----------------------------------------------|
    | p, b       | Previous page                                |
    |------------+----------------------------------------------|
    | TAB, S-TAB | Next/previous link                           |
    |------------+----------------------------------------------|
    | 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:

    - TAB, M-TAB for error navigation.
    - q to bury buffer.