Re: understanding emacs packages

[Tim X <timx@nospam.dev.null>]

knubee <knubee@gmail.com> writes:

>> ,----[ C-h k  control h p  ]
>> |  control h p  runs the command finder-by-keyword
>> |   which is an interactive autoloaded Lisp function in `finder'.
>> | It is bound to  control h p ,  <f1> p ,  <help> p ,  <menu-bar> <help-menu> <finder-by-keyword> .
>> | (finder-by-keyword)
>> |
>> | Find packages matching a given keyword.
>
> Interesting. Just out of curiosity, what is a use scenario for this
> function?
>

1. It provides an easy way to get an overview of the package categories
available on your system.

2. It provides a convenient way to find all the elisp packages relating to
a particular category.

For example, When I run this on my system, I see -

,----
| emacspeak     Audio Desktop
| abbrev        abbreviation handling, typing shortcuts, macros
| bib           code related to the `bib' bibliography processor
| c             support for the C language and related languages
| calendar      calendar and time management support
| comm          communications, networking, remote access to files
| convenience   convenience features for faster editing
| data          support for editing files of data
| docs          support for Emacs documentation
`----

plus a lot of others (this is just a partial listing). If I then go to one
of the items and hit enter, for example the 'c' item, I see

,----
| The following packages match the keyword `c':
| 
| emacspeak-c.el  Speech enable CC-mode and friends -- supports C, C++, Java
| emacspeak-c.el  Speech enable CC-mode and friends -- supports C, C++, Java
| emacspeak-c.el  Speech enable CC-mode and friends -- supports C, C++, Java
| find-file.el    find a file corresponding to this one given a pattern
| tooltip.el      show tooltip windows
| cc-align.el     custom indentation functions for CC Mode
| cc-bytecomp.el  compile time setup for proper compilation
| cc-cmds.el      user level commands for CC Mode
| cc-compat.el    cc-mode compatibility with c-mode.el confusion
| cc-defs.el      compile time definitions for CC Mode
| cc-engine.el    core syntax guessing engine for CC mode
| cc-fonts.el     font lock support for CC Mode
| cc-langs.el     language specific settings for CC Mode
| cc-menus.el     imenu support for CC Mode
| cc-mode.el      major mode for editing C and similar languages
| cc-styles.el    support for styles in CC Mode
`----

again, this is just a partial listing. If I then select one of the files
and hit enter, I get (for example  cc-mode.el)

,----
| Commentary:
| NOTE: Read the commentary below for the right way to submit bug reports!
| NOTE: See the accompanying texinfo manual for details on using this mode!
| Note: The version string is in cc-defs.
| 
| This package provides GNU Emacs major modes for editing C, C++,
| Objective-C, Java, CORBA's IDL, Pike and AWK code.  As of the
| latest Emacs and XEmacs releases, it is the default package for
| editing these languages.  This package is called "CC Mode", and
| should be spelled exactly this way.
| 
| CC Mode supports K&R and ANSI C, ANSI C++, Objective-C, Java,
| CORBA's IDL, Pike and AWK with a consistent indentation model
| across all modes.  This indentation model is intuitive and very
| flexible, so that almost any desired style of indentation can be
| supported.  Installation, usage, and programming details are
| contained in an accompanying texinfo manual.
| 
| CC Mode's immediate ancestors were, c++-mode.el, cplus-md.el, and
| cplus-md1.el..
| 
| To submit bug reports, type "C-c C-b".  These will be sent to
| bug-gnu-emacs@gnu.org (mirrored as the Usenet newsgroup
| gnu.emacs.bug) as well as bug-cc-mode@gnu.org, which directly
| contacts the CC Mode maintainers.  Questions can sent to
| help-gnu-emacs@gnu.org (mirrored as gnu.emacs.help) and/or
| bug-cc-mode@gnu.org.  Please do not send bugs or questions to our
| personal accounts; we reserve the right to ignore such email!
| 
| Many, many thanks go out to all the folks on the beta test list.
| Without their patience, testing, insight, code contributions, and
| encouragement CC Mode would be a far inferior package.
| 
| You can get the latest version of CC Mode, including PostScript
| documentation and separate individual files from:
| 
|     http://cc-mode.sourceforge.net/
| 
| You can join a moderated CC Mode announcement-only mailing list by
| visiting
| 
|    http://lists.sourceforge.net/mailman/listinfo/cc-mode-announce
`----

which is the commentry section from the elisp file. 

So, C-h p can be a useful tool to explore your emacs environment. When you
see a package category that looks interesting, you can hit enter and find
all the elisp files that correspond to that category. When you see a file
that looks interesting, you can hit enter to see the commentry section from
the file, which generally gives you an overview of what functionality that
file provides, where to get more information and what you may need to do to
take advantage of the functions it offers. 

In short, C-h p is yet another of the comprehensive help tools available in
emacs that can assist you to discover some of the (sometimes non-obvious)
features and power available in the editor. Being done in elisp, it also
has the nice property that it gets updated automatically as you add
additional packages (i.e. its not just limited to what is bundled in
emacs).

Tim

-- 
tcross (at) rapttech dot com dot au