To run this module, place this command somewhere in the configuration:
Module FvwmPerl [params]
or:
ModuleSynchronize FvwmPerl [params]
if you want to immediately start to send commands to FvwmPerl.
AddToFunc StartFunction I Module FvwmPerl
There are several command line switches:
FvwmPerl [ --eval line ] [ --load file ] [ --preprocess [ --quote char ] [ --winid wid ] [ --cmd ] [ --nosend ] [ --noremove ] [ line | file ] ] [ --export [names] ] [ --stay ] [ --nolock ] [ alias ]
Long switches may be abbreviated to short one-letter switches.
-e|--eval line - evaluate the given perl code
-l|--load file - evaluate perl code in the given file
-p|--preprocess [ file ] - preprocess the given fvwm config file
The following 5 options are only valid together with --preprocess option.
-c|--cmd line - an fvwm command to be preprocessed instead of file
-q|--quote char - change the default '%' quote
-w|--winid wid - set explicit window context (should begin with digit, may be in oct or hex form; this window id overwrites implicit window context if any)
--nosend - do not send the preprocessed file to fvwm for Reading, the default is send. Useful for preprocessing non fvwm config files.
--noremove - do not remove the preprocessed file after sending it to fvwm for Reading, the default is remove. Useful for debugging.
-x|--export [names] - define fvwm shortcut functions (by default, two functions named ``Eval'' and ``.''). This option implies --stay.
-s|--stay - continues an execution after --eval, --load or --preprocess are processed. By default, the module is not persistent in this case, i.e. --nostay is assumed.
--nolock - when one of the 3 action options is given, this option causes unlocking fvwm immediately. By default the requested action is executed synchronously; this only makes difference when invoked like:
ModuleSynchronous FvwmPerl --preprocess someconfig.ppp
If --nolock is added here, ModuleSynchronous returns immediately. Note that Module returns immediately regardless of this option.
ModuleSynchronous FvwmPerl FvwmPerl-JustTest
SendToModule FvwmPerl-JustTest eval $a = 2 + 2; $b = $a
SendToModule FvwmPerl-JustTest eval cmd("Echo 2 + 2 = $b")
KillModule FvwmPerl FvwmPerl-JustTest
The following code snippet adds ability of arithmetics and string scripting to certain lines that need this. To use this, you want to start FvwmPerl as your first command so that other commands may be asked to be preprosessed.
ModuleSynchronize FvwmPerl
AddToFunc .
+ I SendToModule FvwmPerl preprocess -c -- $*
. Exec exec xterm -name xterm-%{++$i}% # use unique name
. GotoDesk 0 %{ $[desk.n] + 1 }% # go to next desk
. Exec exec %{ -x "/usr/bin/X11/aterm" ? "aterm" : "xterm" }% -sb
# center a window
Next (MyWindow) . Move \
%{($WIDTH - $[w.width]) / 2}%p %{($HEIGHT - $[w.height]) / 2}%p
. Exec exec xmessage %{2 + 2}% # simple calculator
. %{main::show_message(2 + 2, "Yet another Calculator"); ""}%
A special function cmd(``command'') may be used in perl code to send commands back to fvwm.
If perl code contains an error, it is printed to the standard error stream with the [FvwmPerl][eval]: header prepended.
A special function cmd(``command'') may be used in perl code to send commands back to fvwm.
If perl code contains an error, it is printed to the standard error stream with the [FvwmPerl][load]: header prepended.
The quote parameter changes perl code delimiters. If a single char is given, like '@', the delimiters are @{ ... }@. If the given quote is 2 chars, like <>, the quotes are <{ ... }>
The perl code is substituted for the result of its evaluation. I.e. %{$a = ``c''; ++$a}% is replaced with ``d''.
The evaluation is unlike eval and load is done under the package PreprocessNamespace and without use strict, so you are free to use any variable names without fear of conflicts. Just don't use uninitialized variables to mean undef or empty list (they may be in fact initialized by the previous preprocess action), and do a clean-up if needed. The variables and function in the main package are still available, like ::cmd() or ::skip(), but it is just not a good idea to access them while preprocessing.
There is a special function include(file) that loads a file, preprocesses it and returns the preprocessed result. Avoid recursion.
If any embedded perl code contains an error, it is printed to the standard error stream and prepended with the [FvwmPerl][preprocess]: header. The result of substitution is empty in this case.
The following variables may be used in the perl code:
$USER, $DISPLAY, $WIDTH, $HEIGHT, $FVWM_VERSION, $FVWM_MODULEDIR, $FVWM_DATADIR, $FVWM_USERDIR
The following line based directives are recognized when preprocessing. They are processed after the perl code (if any) is substituted.
Examples:
%Prefix "AddToFunc SwitchToWindow I"
Iconify off
WindowShade off
Raise
WarpToWindow 50 50
%End
%ModuleConfig FvwmPager destroy
Colorset 0
Font lucidasans-10
DeskTopScale 28
MiniIcons
%End ModuleConfig FvwmPager
%Prefix "All (MyWindowToAnimate) ResizeMove "
100 100 %{($WIDTH - 100) / 2}% %{($HEIGHT - 100) / 2}%
%Repeat %{$count}%
br w+2c w+2c w-1c w-1c
%End
%Repeat %{$count}%
br w-2c w-2c w+1c w+1c
%End
%End Prefix
Additional preprocess parameters --nosend and --noremove may be given too. See their description at the top.
Function names (func-names) may be separated by commas or/and whitespace. By default, two functions ``Eval'' and ``.'' are assumed.
The actual action defined in a function is guessed from the function name if possible, where function name ``.'' is reserved for preprocess action.
For example, any of these two fvwm commands
SendToModule MyPerl export PerlEval,PP FvwmPerl --export PerlEval,PP MyPerl
define the following two shortcut functions:
DestroyFunc PerlEval AddToFunc I SendToModule MyPerl eval $* DestroyFunc PP AddToFunc I SendToModule MyPerl preprocess -c -- $*
These 4 actions may be requested in one of 3 ways: 1) in the command line when FvwmPerl is invoked (in this case FvwmPerl is short-lived unless --stay or --export is also given), 2) by sending the corresponding message in fvwm config using SendToModule, 3) by calling the corresponding perl function in perl code.
Function names should be separated by commas or/and whitespace. If $func_names is empty then functions ``Eval'' and ``.'' are assumed.
This example causes FvwmPerl to suspend its execution for one minute:
SendModule FvwmPerl eval unlock(); sleep(60);
However, verify that there is no way a new message is sent by fvwm while the module is busy, and fvwm stays locked on this new message for too long. See also the detach solution if you need long lasting operations.
If you use detach(), better only send commands to fvwm in one process (the main one or the detached one), doing otherwise may often cause conflicts.
See FVWM::Module::Toolkit
$a, $b, ... $h
@a, @b, ... @h
%a, %b, ... %h
They all are initialized to the empty value and may be used to store a state between different calls to FvwmPerl actions (eval and load).
If you need more readable variable names, either write ``no strict 'vars';'' at the start of every perl code or use a hash for this, like:
$h{id} = $h{first_name} . " " . $h{second_name}
or use a package name, like:
@MyMenu::terminals = qw( xterm rxvt );
$MyMenu::item_num = @MyMenu::terminals;
There may be a configuration option to turn strictness on and off.
Additionally, a message stop causes a module to quit.
A message unexport [func-names] undoes the effect of export, described in the ACTIONS section.
A message dump dumps the contents of the changed variables (not yet).
SendToModule FvwmPerl eval $h{dir} = $ENV{HOME}
SendToModule FvwmPerl eval load($h{dir} . "/test.fpl")
SendToModule FvwmPerl load $[HOME]/test.fpl
SendToModule FvwmPerl preprocess config.ppp
SendToModule FvwmPerl export Eval,PerlEval,PerlLoad,PerlPP
SendToModule FvwmPerl unexport PerlEval,PerlLoad,PerlPP
SendToModule FvwmPerl stop
The following example handles root backgrounds in fvwmrc. All these commands may be added to StartFunction.
Module FvwmPerl --export PerlEval
# find all background pixmaps for a later use
PerlEval $a = $ENV{HOME} . "/bg"; \
opendir DIR, $a; @b = grep { /xpm$/ } readdir(DIR); closedir DIR
# build a menu of background pixmaps
AddToMenu MyBackgrounds "My Backgrounds" Title
PerlEval foreach $b (@b) \
{ cmd("AddToMenu MyBackgrounds '$b' Exec fvwm-root $a/$b") }
# choose a random background to load on start-up
PerlEval cmd("AddToFunc \
InitFunction + I Exec exec fvwm-root $a/" . $b[int(random(@b))])
SendToModule FvwmPerl eval $$d = "$[DISPLAY]"
-SendToModule FvwmPerl eval $d = "$ENV{DISPLAY}"
SendToModule FvwmPerl eval \
cmd("Echo desk=$d, display=$$d")
SendToModule FvwmPerl preprocess -c \
Echo desk=%("$d")%, display=%{$$d}%
Another solution to avoid escaping of special symbols like dollars and backslashes is to create a perl file in ~/.fvwm and then load it:
SendToModule FvwmPerl load build-menus.fpl
If you need to preprocess one command starting with a dash, you should precede it using ``--''.
# this prints the current desk, i.e. "0"
SendToModule FvwmPerl preprocess -c Echo "$%{$a = "c"; ++$a}%"
# this prints "$d"
SendToModule FvwmPerl preprocess -c -- -Echo "$%{"d"}%"
# this prints "$d" (SendToModule expands $$ to $)
SendToModule FvwmPerl preprocess -c -- -Echo "$$%{"d"}%"
# this prints "$$d"
-SendToModule FvwmPerl preprocess -c -- -Echo "$$%{"d"}%"
Again, it is suggested to put your command(s) into file and preprocess the file instead.
Here are more pairs of equivalent lines:
Module FvwmPerl --load "my.fpl" --stay
Module FvwmPerl -e 'load("my.fpl")' -s
SendToModule FvwmPerl preprocess --quote '@' my.ppp
SendToModule FvwmPerl eval preprocess({quote => '@'}, "my.ppp");
Warning, you may affect the way FvwmPerl works by evaluating appropriate perl code, this is considered a feature not a bug. But please don't do this, write your own fvwm module in perl instead.
Basically, in your perl code you may use any function or class method from the perl library installed with fvwm, see the man pages of perl packages General::FileSystem, General::Parse and FVWM::Module.