NAME
Debug::Mixin - Make your applications and modules easier to debugSYNOPSIS
package my_module ;
# load Debug::Mixin
use Debug::Mixin
{
BANNER => "my banner",
# available at any point in the debugger
DEBUGGER_SUBS =>
[
{
NAME => CheckDependencyMatrix
ALIASES => [qw(dm_cdm cdm)],
DESCRIPTION => "a short description of what this sub is for",
HELP => "a long, possibly multi line description displayed"
. "when the user needs it",
SUB => sub{},
}
],
} ;
# add breakpoints
AddBreakpoint
(
NAME => 'hi'
FILTERS =>
[
sub
{
my (%filter) = @_ ;
$filter{ARGS}{TYPE} eq 'DEPEND' ; # true will enable the actions
}
]
ACTIONS =>
[
sub
{
my (%filter) = @_ ;
print DumpTree $filter{ARGS}{COMPLEX_ELEMENT} ;
return JUMP_TO_DEBUGGER # want to jump into debugger
}
]
DEBUGGER_SUBS=>
[
{
NAME => 'BreakpointDebuggerSub',
DESCRIPTION => "a short description of what this sub is for",
HELP => "a long, possibly multi line description displayed"
. "when the user needs it",
SUB => sub{},
}
]
LOCAL_STORAGE => {}
ALWAYS_USE_DEBUGGER => 0 # let subs decide if we jump in the debugger
ACTIVE => 1
)
# use the breakpoints
sub DoSomething
{
#DEBUG
my %debug_data =
(
TYPE => 'VARIABLE'
, VARIABLE_NAME => $key
, VARIABLE_VALUE => $value
, ...
) ;
#DEBUG
$DB::single = 1 if(Debug::Mixin::IsDebuggerEnabled() && Debug::Mixin::CheckBreakpoint(%debug_data)) ;
# or
if(Debug::Mixin::IsDebuggerEnabled())
{
%debug_data =
(
TYPE => 'VARIABLE'
, ...
) ;
$DB::single = 1 if(Debug::Mixin::CheckBreakpoint(%debug_data, MORE_DATA => 1)) ;
}
DESCRIPTION
This module help you define breakpoints for your own module or applications making them easier to debug.
DOCUMENTATION
Lately,I've been speculating about architectures that would allow us to debug them more easily. Logging, aspect oriented, web interface to internals are some examples of techniques already in use.
The perl debugger already allows us to do a lot of tricky testing before displaying a prompt or stopping only when certain conditions are met. I believe in making debugging even more practical and intelligent.
My theory is simple, actively present data, from your code, and check if a breakpoint matches. This is, in theory, not very different from smart breakpoints in the debugger except the breakpoints are defined in files outside the debugger and are part of the module distribution. The place where this breakpoints triggers are not defined by the breakpoints but by the code being debugged.
Finding where the breakpoints should be checked is best determined while writing the code though they can be added later making your module more . This, of course, doesn't stop you from using the debugger in a normal fashion, with or without the help of these "code called" breakpoints
In your module
use Debug::Mixin ;
...
$DB::single = 1 if(Debug::Mixin::IsDebuggerEnabled() && Debug::Mixin::CheckBreakpoint(%debug_data)) ;At the cost of a subroutine call, you get checking of breakpoints at a position you deem strategic and the possibility to stop in the debugger if any of the breakpoints actions flag to stop.
I'd check if the cost has a real impact before trying to reduce it. you could write:
use Filter::Uncomment GROUPS => [ debug_mixin => ['DM'] ] ;
use Debug::Mixin ;
...
##DM $DB::single = 1 if(Debug::Mixin::IsDebuggerEnabled() && Debug::Mixin::CheckBreakpoint(%debug_data)) ;You'll now pay only if you are actively using Debug::Mixin to debug your application/modules. The only cost being the filtration of the code if, and only if, you decide to uncomment. if you don't, the cost is practically zero.
Have I used this in any real project, PBS on CPAN, and it did really help a lot with very complex problems. Mainly because it let me run debugging very fast but also because the check point were put in the code before I had any problems saving me time to find out where I should place them.
DEBUG SESSION
script Debug::Mixin aware
perl -d script.pl --argument_loading_plenty_breakpointsscript doesn't have to be aware of modules debugging facilities, only modules using Debug::Mixin have to
perl -d -MDebug::Mixin='LoadBreakpointsFiles=file' script.pl
> Using Debug::Mixin banner, use 'dm_help' for Debug::Mixin help.
> dm_help
dm_subs() list and run debugging subs
dm_load(@files) load breakpoints files
# all breakpoints functions take a regex
dm_bp(qr//) list breakpoints
dm_activate(qr//) activate breakpoints
dm_deactivate(qr//) deactivate breakpoints
dm_use_debugger(qr//) jump in debugger
dm_dont_use_debugger(qr//) jump in debugger only if a breakpoint action says to
> run part of the program ...
> Breakpoints display information (eventually interacting with the user)
> stop at a breakpoint, if local commands are available interact with the user, display their documentationSUBROUTINES/METHODS
import
Called for you by Perl
SetupElement
Private function
EnableDebugger
Globally Enables or disables this module.
Debug::Mixin::EnableDebugger(0) ;
Debug::Mixin::EnableDebugger(1) ;IsDebuggerEnabled
Returns the state of this module.
my $status = Debug::Mixin::IsDebuggerEnabled() ;AddBreakpoint
use Debug::Mixin ;
AddBreakpoint
(
NAME => 'add dependencies'
FILTERS =>
[
sub
{
my (%filter) = @_ ;
$filter{ARGS}{TYPE} eq 'DEPEND' ; # true will enable the actions
}
]
ACTIONS =>
[
sub
{
my (%filter) = @_ ;
print DumpTree $filter{ARGS}{COMPLEX_ELEMENT} ;
return JUMP_TO_DEBUGGER # want to jump into debugger
}
]
DEBUGGER_SUBS =>
[
{
NAME => 'CheckDependencyMatrix',
ALIASES => [qw(dm_cdm cdm)],
DESCRIPTION => "a short description of what this sub is for",
HELP => "a long, possibly multi line description displayed"
. "when the user needs it",
SUB => sub{},
}
]
LOCAL_STORAGE => {}
ALWAYS_USE_DEBUGGER => 0 # let subs decide if we jump in the debugger
ACTIVE => 1
)Breakpoint elements
NAME
The name of the breakpoint, you can remove and otherwise manipulate breakpoints by name.
FILTERS
Used to enable or disable all the actions with a single check. FILTERS is a list of sub references. The references are passed the argument you pass to CheckBreakpoints and :
DEBUG_MIXIN_BREAKPOINT
A reference to the breakpoint.
DEBUG_MIXIN_CALLED_AT
a hash containing the file and line where CheckBreakpoints was called.
ACTIONS
ACTIONS is a list of sub references. All the subs are run. All debugging functionality (ex: activating or adding breakpoints) are available within the subs.
DEBUGGER_SUBS
List of functions available, at the time the breakpoint matches, when running under the debugger. Debug::Mixin will present you with the list of local functions and allow you to run any of the functions.
each entry must have follow the following format
{ NAME => 'CheckDependencyMatrix', ALIASES => [qw(dm_cdm cdm)], DESCRIPTION => "a short description of what this sub is for", HELP => "a long, possibly multi line description displayed" . "when the user needs it", SUB => sub{}, }ALWAYS_USE_DEBUGGER
If the breakpoint is active, CheckBreakpoints will always return true.
ACTIVE
The breakpoint actions will only be called if ACTIVE is set.
LOCAL_STORAGE
A user storage area within the breakpoint. You can store and manipulate it as you wish. You must use this area as Debug::Mixin only allows certain fields in a breakpoint.
This item can be manipulated through the breakpoint reference passed to filters and actions.
A warning is displayed if you override an existing breakpoint. A breakpoint creation history is kept.
CheckBreakPointDefinitions
Checks the validity of the user supplied breakpoint definitions. Croaks on error.
LoadBreakpointsFiles
Evaluates a perl script. The main purpose of the script is to define breakpoints but the script can also query Debug::Mixin and change existing breakpoints or run any perl code deemed fit.
Croaks on error, return(1) on success.
RemoveBreakpoints
Removes one or more breakpoint matching the name regex passed as argument. A warning is displayed for each removed breakpoint.
Debug::Mixin::RemoveBreakpoints(qr/dependencies/) ;Returns the number of removed breakpoints.
RemoveAllBreakpoints
Removes all breakpoints. No message is displayed.
Debug::Mixin::RemoveAllBreakpoints();ListDebuggerSubs
List all the debugger subs registered by modules loading Debug::Mixin on STDOUT.
ListBreakpoints
List, on STDOUT, all the breakpoints matching the name regex passed as argument.
GetBreakpoints
Returns a reference to all the breakpoints. Elements are returned in the insertion order.
Use this only if you know what you are doing.
ActivateBreakpoints
Activate all the breakpoints matching the name regex passed as argument.
Only active breakpoints are checked by Debug::Mixin.
DeactivateBreakpoints
Deactivate all the breakpoints matching the name regex passed as argument.
Only active breakpoints are checked by when you call CheckBreakpoints.
ActivateAlwaysUseDebugger
Sets all breakpoints matching the name regex passed as argument to always jumps to the perl debugger.
DeactivateAlwaysUseDebugger
Sets all breakpoints matching the name regex passed as argument, to never jumps to the perl debugger.
CheckBreakpoints
Check a user state against all registered breakpoints. Returned value tells caller if it should jump into the debugger.
if(Debug::Mixin::IsDebuggerEnabled())
{#bp local subs
%debug_data =
(
# user data passed to the breakpoint actions
TYPE => '...'
, COMMENT => '...'
, ...
) ;
$DB::single = 1 if(Debug::Mixin::CheckBreakpoint(%debug_data)) ;
}HandleBreakpointSubInteraction
Private subroutine handling user interaction in a debugger session.
dm_help
Displays the commands made available by Debug::Mixin in the debugger.
dm_subs
List all the available debugging subs and interacts with the user to run them.
Output
Prints the passed arguments
TO DO
More test, testing the module through the perl debugger's automation.
BUGS AND LIMITATIONS
None so far.
AUTHOR
Khemir Nadim ibn Hamouda
CPAN ID: NKH
mailto:nadim@khemir.netLICENSE AND COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Debug::MixinYou can also look for information at:
AnnoCPAN: Annotated CPAN documentation
RT: CPAN's request tracker
Please report any bugs or feature requests to L <bug-my $storage_ref = debug-mixin@rt.cpan.org>.
We will be notified, and then you'll automatically be notified of progress on your bug as we make changes.
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