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[sepia.git] / sepia.info

This is sepia.info, produced by makeinfo version 4.8 from sepia.texi.

INFO-DIR-SECTION Emacs
START-INFO-DIR-ENTRY
* Sepia: (sepia).    Simple Emacs Perl Integration.
END-INFO-DIR-ENTRY

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File: sepia.info,  Node: Top,  Next: Introduction,  Prev: (dir),  Up: (dir)

SEPIA
*****

   Sepia is a set of Perl development tools for Emacs supporting code
navigation and interactive evaluation.

* Menu:

* Introduction::
* Editing::
* Interactive Perl::
* Customization::
* Internals::
* Credits::
* Function Index::

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File: sepia.info,  Node: Introduction,  Next: Editing,  Prev: Top,  Up: Top

1 Introduction
**************

Sepia is a set of tools for Perl development in Emacs.  Its goal is to
extend CPerl mode to support fast code navigation and interactive
development.  It is inspired by Emacs' current support for a number of
other languages, including Lisp, Python, and Emacs Lisp.

* Menu:

* Getting Started::
* Philosophy::

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File: sepia.info,  Node: Getting Started,  Next: Philosophy,  Prev: Introduction,  Up: Introduction

1.1 Getting Started
===================

To install Sepia, its Emacs Lisp files must be in Emacs' `load-path',
and the `lib' directory must be in Perl's `@INC'.  Assuming that Sepia
has been unpacked in `~/sepia', it can be installed by adding the
following lines to `~/.emacs':

     (add-to-list 'load-path "~/sepia")
     (setq sepia-perl5lib (list (expand-file-name "~/sepia/lib")))
     (defalias 'perl-mode 'sepia-mode)
     (require 'sepia)

   Then to bring up the interactive Perl prompt, type `M-x sepia-repl'.

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File: sepia.info,  Node: Philosophy,  Prev: Getting Started,  Up: Introduction

1.2 Philosophy
==============

A development environment should support three activities: code
spelunking, interaction, and customization.  Emacs as an environment for
developing Emacs Lisp thoroughly supports all of them: It has commands
to visit individual functions' code and documentation, commands to
evaluate or step through expressions, and an architecture that
encourages customization in Emacs Lisp.  As an environment for Perl,
however, it is lacking: there is limited interactivity with the Perl
debugger, and reasonable documentation browsing, but no support for
navigating, editing, and re-evaluating code.  Sepia attempts to remedy
the situation.

   Modern IDEs also support these three activities, but do so awkwardly.
Rather than having functions to visit definitions (`find-function') and
search for functions (`apropos'), they clutter the screen with class
and file trees.  Rather than supporting interactive evaluation of small
pieces of code, they perform background semantic checking on whole
projects and highlight errors.  Rather than allowing minor
customizations to grow organically into features, they support limited
configuration files and baroque plug-in APIs.  Sepia tries to adhere to
the apparent Emacs philosophy that rich semantic information should be
unobtrusive, and that the best way to build working code is to start by
experimenting with small pieces.

   Language support packages for Emacs vary widely in the degree to
which they make use of or replace existing Emacs features.  Minimal
modes provide keyword-based syntax highlighting and an unadorned comint
buffer as an interpreter.  Others provide their own specialized
equivalents of comint, eldoc, completion, and other Emacs features.
Sepia takes a third approach by trying to do as much as possible with
existing Emacs features, even when they are not optimal for Perl.  For
example, it uses comint to communicate with the subprocess, eldoc to
display documentation, and grep to list source locations.

   This approach has three advantages: First, it maximizes the number of
features that can be supported with limited development time.  Second,
it respects users' settings.  A seasoned Emacs user may have changed
hundreds of settings, so a mode that reimplements features will have to
support equivalent settings, and will force the user to re-specify them.
Finally, this approach respects decades of development spent, as Neal
Stephenson put it, "focused with maniacal intensity on the deceptively
simple-seeming problem of editing text."  Many non-obvious choices go
into making a polished interface, and while a reimplementation gets rid
of accumulated cruft, it must rediscover these hidden trade-offs.

   Anyways, I hope you enjoy using Sepia.  Its development style is
strange for someone used Perl's typical mix of one-liners and
edit-save-run, but once you are accustomed to it, you may find it very
effective.

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File: sepia.info,  Node: Editing,  Next: Interactive Perl,  Prev: Introduction,  Up: Top

2 Editing
*********

Sepia's first contribution is a set of commands to explore a Perl
codebase.  These include commands to browse and display documentation,
to find function definitions, and to query a cross-reference database of
function and variable uses.  Sepia also provides intelligent symbol
completion.

* Menu:

* Completion::
* Navigation::
* Documentation::

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File: sepia.info,  Node: Completion,  Next: Navigation,  Prev: Editing,  Up: Editing

2.1 Completion
==============

Sepia implements partial-word completion that communicates with the
inferior Perl process.  For example, `%S:X:v_u' completes to
`%Sepia::Xref::var_use' when Sepia is loaded.  This completion only
operates on functions and global variables known to the Perl
interpreter, so it works best when code and interpreter are in sync.

   More precisely, completion examines the text before point and tries
each of the following in turn, using the first successful approach:

  1. If the text looks like a method call (e.g. `$object->f' or
     `Class->f'), complete on methods.

  2. If it looks like a variable (e.g. `%hash' or `$scalar'), complete
     on variables.

  3. Complete on modules and functions.

  4. Otherwise, complete on Perl built-in operators.

   For each of the first three cases, completions candidates are first
generated by splitting the text on characters `[:_]' and matching the
resulting word parts.  For example, `X:a_b' will complete to all
symbols matching `^X[^:]*:+a[^:_]*_b' such as `Xref::a_bug' and
`X::always_bites_me'.  If no matches result, the text is treated as an
acronym.  For example, `dry' will complete to `dont_repeat_yourself'.

   Completion is performed by the following commands:
`M-x sepia-complete-symbol'
     Complete the symbol before point as described above.  Note that
     this does not consider lexical scope, and is always case-sensitive,
     independent of `completion-ignore-case'.

`TAB'
`M-x sepia-indent-or-complete'
     First try to reindent the current line.  If its indentation does
     not change, then try to expand an abbrev at point (unless
     `sepia-indent-expand-abbrev' is `nil').  If no abbrev is expanded,
     then call `sepia-complete-symbol'.


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File: sepia.info,  Node: Navigation,  Next: Documentation,  Prev: Completion,  Up: Editing

2.2 Navigation
==============

Sepia provides several commands for navigating program source.  All of
them rely on information from the inferior Perl process, so it is
important both that it be running, and that its internal representation
of the program match the program source.  The commands marked (Xref)
below also rely on a cross-reference database, which must be explicitly
rebuilt by calling `xref-rebuild' when the program changes.

   There are two basic kinds of navigation commands.  The first kind
jumps directly to the first matching location when possible, prompting
only if no such location is found.  These commands find only a single
location.

`M-. M-.'
`M-x sepia-dwim'
     Guess what kind of identifier is at point, and try to do the right
     thing: for a function, find its definition(s); for a variable,
     find its uses; for a module, view its documentation; otherwise,
     prompt for the name of a function to visit.  `sepia-dwim'
     automatically goes to the first function definition or variable
     use found.

`M-. l'
`M-x sepia-location'
     Jump directly to the definition of the function at point,
     prompting if point is not on a known function.  If multiple
     definitions are found, choose one arbitrarily.  This function is
     similar to `sepia-defs', and the two should probably be merged.

`M-. j'
`M-x sepia-jump-to-symbol'
     Navigate to a function using "ido" interactive completion.  Within
     interactive completion, press <:> to descend into a package, <DEL>
     to ascend to a parent package, and <RET> to go to the
     currently-selected function.


   The second kind of navigation commands always prompts the user -
though usually with a sensible default value - and finds multiple
locations.  When called with a prefix argument, these commands present
their results in a `grep-mode' buffer.  When called _without_ a prefix
argument, they place all results on the found-location ring and jump
directly to the first.  The remaining locations can be cycled through by
calls to `sepia-next'.

`M-. f NAME <RET>'
`M-x sepia-defs'
     Find definition(s) of function NAME.

`M-. m NAME <RET>'
`M-x sepia-module-find NAME <RET>'
     Find the source of module NAME.

`M-. a REGEXP <RET>'
`M-x sepia-apropos REGEXP <RET>'
     Find definitions of all functions whose names match REGEXP.

`M-. c NAME <RET>'
`M-x sepia-callers NAME <RET>'
     (Xref) Find calls to function NAME.

`M-. C NAME <RET>'
`M-x sepia-callees NAME <RET>'
     (Xref) Find the definitions of functions called by NAME.

`M-. v NAME <RET>'
`M-x sepia-var-uses NAME <RET>'
     (Xref) Find uses of the global variable NAME.

`M-. V NAME <RET>'
`M-x sepia-var-defs NAME <RET>'
     (Xref) Find definitions of global variable NAME.  Since Perl's
     global variables are not declared, this is rarely useful


   Finally, there are several other navigation-related commands that do
not fit into either of the above categories.

`M-,'
`M-x sepia-next'
     Cycle through the definitions found by the previous <M-.> search.

`M-. r'
`M-x sepia-rebuild'
     Rebuild the cross-reference database by walking the op-tree and
     stashes.

`M-. t'
`M-x find-tag'
     Execute the `find-tag' command typically bound to <M-.>.


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File: sepia.info,  Node: Documentation,  Prev: Navigation,  Up: Editing

2.3 Documentation
=================

Sepia can be used to browse installed modules' documentation, to format
and display the current buffer's POD, and to browse the list of modules
installed on the system.

`M-. d NAME <RET>'
`M-x sepia-perldoc-this'
     View documentation for module NAME or Perl manual page NAME.

`C-c C-d'
`M-x sepia-view-pod'
     Format and view the current buffer's documentation.

`sepia-package-list'
     Browse a tree of installed packages.  This lists only the top-level
     packages from installed distributions, so if package `My::Stuff'
     also provides `My::Stuff::Details', it will not be displayed.  When
     Emacs-w3m is available, each module is linked to its documentation.

`sepia-module-list'
     Browse a tree of both top-level and internal packages, like
     `sepia-package-list'.


   Sepia also integrates with eldoc (at least in GNU Emacs >= 22).
Documentation for Perl operators and control structures is taken from
CPerl mode.  Sepia will also display documentation for user-defined
functions if their POD is formatted in the standard way, with functions
described in a "=head2" or "=item" entry.  To load user documentation,
visit the relevant file and type `M-x sepia-doc-update'.

   If `Module::CoreList' is available, Sepia's eldoc function will also
display the first version of Perl with which a module was shipped.
This is intended to give the programmer a sense of when he is creating
external dependencies.

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File: sepia.info,  Node: Interactive Perl,  Next: Customization,  Prev: Editing,  Up: Top

3 Interactive Perl
******************

Sepia's second main contribution is an interactive interface (REPL) to
an inferior Perl process.  The interface is based on GUD mode, and
inherits many of its bindings; this chapter discusses only the Sepia
extensions.  To start or switch to the repl, type `M-x sepia-repl'.  As
in Sepia mode, <TAB> in the REPL performs partial-word completion with
`sepia-complete-symbol'.

   Sepia also provides a number of other ways to evaluate pieces of
code in Perl, and commands to process buffer text using the inferior
process.

* Menu:

* Shortcuts::
* Debugger::
* Evaluation::
* Mutilation::
* Scratchpad::

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File: sepia.info,  Node: Shortcuts,  Next: Debugger,  Prev: Interactive Perl,  Up: Interactive Perl

3.1 Shortcuts
=============

"Shortcuts" are commands handled specially by the REPL rather than
being evaluated as Perl code.  They either communicate with the REPL
function, or provide a convenient interface to variables in the Sepia
package.  Shortcuts are prefixed by a comma (<,>), and may be
abbreviated to the shortest unique prefix.

`cd DIR'
     Change Perl's current directory to DIR.

`debug [VAL]'
     Turn Sepia debugger hook on or off, or toggle if VAL is missing.

`define NAME ['DOC'] BODY...'
     Define NAME as a shortcut for Perl code BODY, with optional
     documentation DOC, surrounded by single quotes.  BODY is passed
     the raw command-line text as its first argument.

`delete'
     Delete the current breakpoint.

`format TYPE'
     Set the output format to TYPE, either "dumper" (using
     `Data::Dumper'), "dump" (`Data::Dump'), "yaml" (`YAML'), or
     "plain" (stringification).  Default: "dumper".

`help'
     Display a list of shortcuts.

`lsbreak'
     List breakpoints.

`methods NAME [REGEXP]'
     Display a list of functions defined in package NAME and its
     `ISA'-ancestors matching optional pattern REGEXP.

`package NAME'
     Set the default evaluation package to NAME.

`pwd'
     Show the process's current working directory.

`quit'
     Exit the inferior Perl process.

`reload'
     Reload `Sepia.pm' and recursively invoke the REPL.  This command is
     mostly of interest when working on Sepia itself.

`shell [COMMAND]'
     Execute shell command COMMAND, displaying its standard output and
     standard error.

`strict [VAL]'
     Set evaluation strictness to VAL, or toggle it if VAL is not
     given.  Note that turning strictness off and on clears the REPL's
     lexical environment.

`undef NAME'
     Undefine shortcut NAME.  *Warning*: this can equally be used to
     remove built-in shortcuts.

`wantarray [VAL]'
     Set the evaluation context to VAL, or toggle between scalar and
     array context.

`who PACKAGE [REGEXP]'
`who [REGEXP]'
     List identifiers in PACKAGE (main by default) matching optional
     REGEXP.


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File: sepia.info,  Node: Debugger,  Next: Evaluation,  Prev: Shortcuts,  Up: Interactive Perl

3.2 Debugger
============

Sepia uses Perl's debugger hooks and GUD mode to support conditional
breakpoints and single-stepping, and overrides Perl's `die()' to invoke
the debugger rather than unwind the stack.  This makes it possible to
produce a backtrace, inspect and modify global variables, and even
continue execution when a program tries to kill itself.  If the
PadWalker module is available, Sepia also provides functions to inspect
and modify lexical variables.

   The debugger has its own set of shortcuts, also prefixed by a comma.

`backtrace'
     Show a backtrace.

`break FILE:LINE [EXPR]'
     Set a breakpoint in FILE at LINE.  If EXPR is supplied, stop only
     if it evaluates to true.

`down N'
`up N'
     Move the current stack frame up or down by N (or one) frames.

`inspect [N]'
     Inspect lexicals in the current frame or frame N, counting upward
     from 1.

`lsbreak'
     List breakpoints.

`next [N]'
     Advance N (or one) lines, skipping subroutine calls.

`quit'
`die'
`warn'
     Continue as the program would have executed without debugger
     intervention, dying if the debugger was called from `die()'.

`return EXPR'
     Continue execution as if `die()' had returned the value of EXPR,
     which is evaluated in the global environment.

`step [N]'
     Step forward N (or one) lines, descending into subroutines.


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File: sepia.info,  Node: Evaluation,  Next: Mutilation,  Prev: Debugger,  Up: Interactive Perl

3.3 Evaluation
==============

When interactive Perl is running, Sepia can evaluate regions of code in
the inferior Perl process.  The following commands assume that this
process has already been started by calling `sepia-repl'.

`C-M-x'
`M-x sepia-eval-defun'
     Evaluate the function around point in the inferior Perl process.
     If it contains errors, jump to the location of the first.

`C-c C-l'
`M-x sepia-load-file'
     Save the current buffer, then reload its file and if warnings or
     errors occur, display an error buffer.  With a prefix argument,
     also rebuild the cross-reference index.

`C-c e'
`M-x sepia-eval-expression <RET> EXPR <RET>'
     Evaluate EXPR in scalar context and echo the result.  With a
     prefix argument, evaluate in list context.

`C-c!'
`sepia-set-cwd'
     Set the REPL's working directory to the current buffer's directory.


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File: sepia.info,  Node: Mutilation,  Next: Scratchpad,  Prev: Evaluation,  Up: Interactive Perl

3.4 Mutilation
==============

Sepia contains several functions to operate on regions of text using the
interactive Perl process.  These functions can be used like standard
one-liners (e.g. `perl -pe ...'), with the advantage that all of the
functions and variables in the interactive session are available.

`M-x sepia-perl-pe-region <RET> CODE <RET>'
     Evaluate CODE on each line in the region with `$_' bound to the
     line text, collecting the resulting values of `$_'.  With a prefix
     argument, replace the region with the result.

`M-x sepia-perl-ne-region <RET> CODE <RET>'
     Evaluate CODE as above, but collect the results instead.

`M-x sepia-perlize-region <RET> CODE <RET>'
     Evaluate CODE once with `$_' bound to the entire region,
     collecting the final value of `$_'.  With a prefix argument,
     replace the region.


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File: sepia.info,  Node: Scratchpad,  Prev: Mutilation,  Up: Interactive Perl

3.5 Scratchpad
==============

Sepia also supports a scratchpad, another form of interaction inspired
by Emacs' `*scratch*' buffer.  To create or switch to the scratchpad,
type `M-x sepia-scratch'.  Scratchpad mode is exactly like Sepia mode,
except <C-j> evaluates the current line and prints the result on the
next line.

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File: sepia.info,  Node: Customization,  Next: Internals,  Prev: Interactive Perl,  Up: Top

4 Customization
***************

While Sepia can be customized in both the Perl and Emacs Lisp, most of
the user-accessible configuration is in the latter.

* Menu:

* Emacs Variables::
* Perl Variables::

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File: sepia.info,  Node: Emacs Variables,  Next: Perl Variables,  Prev: Customization,  Up: Customization

4.1 Emacs Variables
===================

Since Sepia tries where possible to reuse existing Emacs functionality,
its behavior should already be covered by existing customizations.  The
two variables most likely to need customization are
`sepia-program-name' and `sepia-perl5lib'.  General Sepia mode
configuration can be done with `sepia-mode-hook', while REPL-specific
configuration can be done with `sepia-repl-mode-hook'.

`sepia-complete-methods'
     If non-`nil', `sepia-complete-symbol' will complete simple method
     calls of the form `$x->' or `Module->'.  Since the former requires
     evaluation of `$x', this can be disabled.  Default: `T'.

`sepia-eval-defun-include-decls'
     If non-`nil', attempt to generate a declaration list for
     `sepia-eval-defun'.  This is necessary when evaluating some code,
     such as that calling functions without parentheses, because the
     presence of declarations affects the parsing of barewords.
     Default: `T'.

`sepia-indent-expand-abbrev'
     If non-`nil', `sepia-indent-or-complete' will, if reindentation
     does not change the current line, expand an abbreviation before
     point rather than performing completion.  Only if no abbreviation
     is found will it perform completion.  Default: `T'.

`sepia-module-list-function'
     The function to view a tree of installed modules.  Default:
     `w3m-find-file' if Emacs-w3m is installed, or
     `browse-url-of-buffer' otherwise.

`sepia-perldoc-function'
     The function called to view installed modules' documentation.
     Default: `w3m-perldoc' if Emacs-w3m is installed, or
     `cperl-perldoc' otherwise.

`sepia-perl5lib'
     A list of directories to include in `PERL5LIB' when starting
     interactive Perl.  Default: `nil'.

`sepia-prefix-key'
     The prefix to use for for functions in `sepia-keymap'.  Default:
     <M-.>.

`sepia-program-name'
     The Perl program name for interactive Perl.  Default: "perl".

`sepia-use-completion'
     If non-`nil', various Sepia functions will generate completion
     candidates from interactive Perl when called interactively.  This
     may be slow or undesirable in some situations.  Default: `T'.

`sepia-view-pod-function'
     The function called to view the current buffer's documentation.
     Default: `sepia-w3m-view-pod' if Emacs-w3m is available, or
     `sepia-perldoc-buffer' otherwise.


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File: sepia.info,  Node: Perl Variables,  Prev: Emacs Variables,  Up: Customization

4.2 Perl Variables
==================

When Sepia starts up, it evaluates the Perl script in `~/.sepiarc'.
The following variables in the Sepia package control various aspects of
interactive evaluation.

`$PACKAGE'
     The package in which user input is evaluated, determined
     automatically when code is evaluated from a buffer.  Default:
     `main'.

`$PRINTER'
     The function called to format interactive output, normally set
     with the `printer' shortcut.

`$PRINT_PRETTY'
     If true, format some values nicely independent of the value of
     `$PRINTER'.  Currently, this means columnating lists of simple
     scalars.  Default: true.

`$PS1'
     The trailing end of the prompt string, which should end with "> ".
     Default: `"> "'.

`$STOPDIE'
     If true, calls to `die' from interactive code will invoke the Sepia
     debugger.  Default: true.

`$STOPWARN'
     If true, calls to `warn' from interactive code will invoke the
     Sepia debugger.  Default: false.

`$WANTARRAY'
     If true, evaluate interactive expressions in list context.
     Default: true.


   Additional REPL shortcuts can be defined with
`Sepia::define_shortcut'.  For example

     Sepia::define_shortcut time => sub { print scalar localtime, "\n"; 0 },
         'Display the current time.';

   defines a shortcut "time" that displays the current time.  For
details, see the code in `Sepia.pm'.

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File: sepia.info,  Node: Internals,  Next: Credits,  Prev: Customization,  Up: Top

5 Internals
***********

Many things remain unexplained except by the code itself, and some
details mentioned above should probably be given less prominence.  For
developer documentation, please see the POD for `Sepia' and
`Sepia::Xref', and the doc-strings in `sepia.el'.

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File: sepia.info,  Node: Credits,  Next: Function Index,  Prev: Internals,  Up: Top

Credits
*******

Hilko Bengen
     Found and motivated me to fix a bunch of bugs, created Debian
     packages.

Ye Wenbin
     Found and fixed numerous bugs.

Free Software
     Portions of the code were lifted from Emacs-w3m, SLIME, ido, and
     B::Xref, all of which are Free software.


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File: sepia.info,  Node: Function Index,  Prev: Credits,  Up: Top

Function Index
**************

\0\b[index\0\b]
* Menu:

* sepia-apropos:                         Navigation.           (line 60)
* sepia-callees:                         Navigation.           (line 68)
* sepia-callers:                         Navigation.           (line 64)
* sepia-complete-symbol:                 Completion.           (line 34)
* sepia-defs:                            Navigation.           (line 52)
* sepia-dwim:                            Navigation.           (line 20)
* sepia-eval-defun:                      Evaluation.           (line 12)
* sepia-eval-expression:                 Evaluation.           (line 23)
* sepia-indent-or-complete:              Completion.           (line 40)
* sepia-install-eldoc:                   Documentation.        (line 29)
* sepia-jump-to-symbol:                  Navigation.           (line 36)
* sepia-load-file:                       Evaluation.           (line 17)
* sepia-location:                        Navigation.           (line 29)
* sepia-mode:                            Editing.              (line  6)
* sepia-module-find:                     Navigation.           (line 56)
* sepia-module-list:                     Documentation.        (line 25)
* sepia-next:                            Navigation.           (line 85)
* sepia-package-list:                    Documentation.        (line 19)
* sepia-perl-ne-region:                  Mutilation.           (line 17)
* sepia-perl-pe-region:                  Mutilation.           (line 12)
* sepia-perldoc-this:                    Documentation.        (line 12)
* sepia-perlize-region:                  Mutilation.           (line 20)
* sepia-rebuild:                         Navigation.           (line 89)
* sepia-repl:                            Interactive Perl.     (line  6)
* sepia-scratch:                         Scratchpad.           (line  6)
* sepia-var-defs:                        Navigation.           (line 76)
* sepia-var-uses:                        Navigation.           (line 72)
* sepia-view-pod:                        Documentation.        (line 16)


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Tag Table:
Node: Top\x7f187
Node: Introduction\x7f512
Node: Getting Started\x7f933
Node: Philosophy\x7f1558
Node: Editing\x7f4564
Node: Completion\x7f5026
Node: Navigation\x7f6870
Node: Documentation\x7f10219
Node: Interactive Perl\x7f11766
Node: Shortcuts\x7f12503
Node: Debugger\x7f14704
Node: Evaluation\x7f16163
Node: Mutilation\x7f17139
Node: Scratchpad\x7f18091
Node: Customization\x7f18496
Node: Emacs Variables\x7f18797
Node: Perl Variables\x7f21292
Node: Internals\x7f22779
Node: Credits\x7f23139
Node: Function Index\x7f23518
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End Tag Table