source: doc/code.txt @ 5ff830a

$Id$


TYPES / CLASSES / SOURCE FILES
------------------------------

cmd:         Underlying implementation of command table management
             and command dispatching.  Also handles the implementation
             of command aliases.

commands:    Dispatching for commands and handling of their arguments.
             (Commands are the interface exported to the user.)
             Many commands tend to be backed by functions.
             In general, a command takes a string as an argument
             and optionally returns a string.
             At the top of the file is a table mapping
             command names and help to functions implementing them.
             The standard entrypoint for executing a command
             is owl_function_command("foo");
             Commands are only active within specific contexts,
             and attempts to call them from invalid contexts will fail.      

context:     A context specifies the current state of owl, in terms 
             of which modal window is active and which point
             in its life owl is in (eg, in startup, or running).
             This is implemented as a bitmask and there is 
             some hierarchy.  Commands may restrict themselves
             to only running in a limited number of contexts
             to prevent commands from being executed at points
             when they not make sense.  Also, the data from
             the active context (eg, a pointer to an active window)
             may be passed to a command.

dict:        Simple dictionary abstraction mapping from strings to pointers.

editwin:     Text editing window (both multiline and single line).
             Sometimes also referred to as typewin.

filter:      Patterns which match messages.  These may 
             contain multiple filterelements which may be 
             combined together (eg, by "and" and "or").
             
filterelement: An element of a filter which matches on some 
               attribute of a message.

fmtext:      Formatted text routines (handles things like @i{foo}).
             These are particularly useful for building up
             text regions that are to be rendered on-screen,
             as they resize memory as needed, and they have 
             routines for cropping as needed.

functions:   Where most features are implemented.
             Users should always interact with functions through commands.
             In general, functions are abstract entrypoints into the
             system and attempt to hide access to global state.

global:      Global state and variables and toplevel objects.
             owl.h defines "g" as a singleton instance of owl_global.
             Where possible/appropriate, most accesses to global data should
             be from a limited number of files (eg, from owl.c and 
             functions.c).  Consider whether you really need to before
             adding in uses of global.

help:        Help strings for commands and key bindings.
             Most of this is now in keys.c, commands.c, and variables.c,
             along with the definition of commands and keybindings.

keys:        Default key binding definitions for all keymaps.
             This also includes default actions for keymaps.

keybinding:  Binding between a sequence of keypresses and a command.
             When executed, this executes the commands.  The sequence
             of keypresses is kept as a stack.  Keybindings are a part
             of keymaps.

keypress:    Utility routines for translating between keypress values and
             and human-readable key names.

keymap:      Contains both keymap and keyhandler.  A keymap is contains a
             list of keybindings, a sub-keymap, and optionally a
             default handler function.  The sub-keymap is a more
             general keymap which is consulted if the specific keymap
             doesn't contain a match.  (For example, the "global"
             keymap is the ancestor of all other keymaps.)  The
             keyhandler is a collection of keymaps which handles
             checking for key matches within keymaps.  It maintains a
             stack of keypresses and compares them against the
             bindings in keymaps.  It also handles ESC as a prefix for
             Meta.  At any one time, there is exactly one active
             keymap which determines where keybindings are looked for
             (along with its submaps).

list:        Simple list abstraction.  (Uses realloc to resize the list.)

logging:     Interface to incoming / outgoing zephyr logging.

mainwin:     Window that displays the list of messages.
             (Sometimes also referred to as recwin.)

message:     Abstraction to messages.  Currently, messages
             are either of type zephyr or of type admin.

messagelist: List of messages.

owl.c:       main() and signal handlers and other initial setup.
             Also contains the main loop, which is roughly:
             - handle scheduled resizes, and anything that might result
             - while zephyrs are pending, grab incoming zephyrs 
               and handle them (which includes formatting them
               with either perl extension or default formatter
               as part of owl_message_create_from_zephyr).
             - updates mainwin display if there are new zephyrs
             - displays and updates popwins and the terminal as necessary
             - sends characters to the popwin, recwin/mainwin, 
               or typewin/editwin


owl.h:       Prototypes for all types, as well as global constants.

owl_prototypes.h:  Autogenerated prototypes for all functions.
                   Created by codelist.pl.

popwin:      Modal pop-up window container. 
             Usually contains a viewwin for read-only scrolling text.

readconfig:  Perl extension interface.

text:        Text formatting utilities (ie, indenting, truncating, etc)

util:        Misc utility functions that don't fit anywhere yet:
             - sepbar rendering 
             - tokenizing and parsing utilities
             - downstr
             - stristr
             - owl_malloc/free/realloc

variable:    Interface to setting and getting variables.
             Current variable types include bool, int, string, and other.
             There's also an enum type which is variant of int.
             Variables can be created and customized here as well.

varstubs.c:  Autogenerated headers for accessing global variables

view:        A collection of messages determined by a filter.
             Many operations may be performed on the members
             of a view, and a view can be narrowed-to for display.

viewwin:     Read-only scrolling text displayed in a modal popwin.
             This is also sometimes called "popless".

zephyr:      Routines for interfacing to zephyr.

zwrite:      Outgoing zephyrs.  Sends pings on creation,
             handles command arguments, etc.


===========================================================================

CURSES WINDOWS
--------------

The four curses windows on the screen are

  recwin - receiving window
  sepwin - seperator window
  msgwin - message window
  typwin - typing window


===========================================================================


MISC THINGS
-----------

userclue:  right now userclue is just used to decide if you sub to
           classes other than the default.  If you don't it doesn't bother
           making your personal messages bold since there's no point in
           making every message bold.



===========================================================================

Conventions and Design Criteria
-------------------------------

        There are no hard rules for memory allocation.  In general I
        have the caller allocate memory for objects themselves and any
        memory the object creates gets freed with object_free().
        Functions should document if the caller needs to free
        something, and this should be the exception to the rule.

        Owl should be generally useful out-of-the-box without 
        extensive configuration, for most people's needs.  
        People shouldn't have to spend days tweaking
        with config files before being happy switching to it.