NAME
Devel::ptkdb - Perl debugger using a Tk GUI
=head1 DESCRIPTION
ptkdb is a debugger for perl that uses perlTk for a user interface.
Features include:
Hot Variable Inspection
Breakpoint Control Panel
Expression List
Subroutine Tree
=begin html
<body bgcolor=white>
=end html
=head1 SYNOPSIS
To debug a script using ptkdb invoke perl like this:
perl -d:ptkdb myscript.pl
=head1 Usage
perl -d:ptkdb myscript.pl
=head2 Code Pane
=item Line Numbers
Line numbers are presented on the left side of the window. Lines that
have lines through them are not breakable. Lines that are plain text
are breakable. Clicking on these line numbers will insert a
breakpoint on that line and change the line number color to
$ENV{'PTKDB_BRKPT_COLOR'} (Defaults to Red). Clicking on the number
again will remove the breakpoint. If you disable the breakpoint with
the controls on the BrkPt notebook page the color will change to
$ENV{'PTKDB_DISABLEDBRKPT_COLOR'}(Defaults to Green).
=item Cursor Motion
If you place the cursor over a variable (i.e. $myVar, @myVar, or
%myVar) and pause for a second the debugger will evaluate the current
value of the variable and pop a balloon up with the evaluated
result. I<This feature is not available with Tk400.>
If Data::Dumper(standard with perl5.00502)is available it will be used
to format the result. If there is an active selection, the text of
that selection will be evaluated.
=head2 Notebook Pane
=item Exprs
This is a list of expressions that are evaluated each time the debugger stops. The results
of the expresssion are presented heirarchically for expression that result in hashes or lists.
Double clicking on such an expression will cause it to collapse; double clicking again
will cause the expression to expand. Expressions are entered through B<Enter Expr> entry,
or by Alt-E when text is selected in the code pane.
The B<Quick Expr> entry, will take an expression, evaluate it, and replace the entries
contents with the result. The result is also transfered to the 'clipboard' for pasting.
=item Subs
Displays a list of all the packages invoked with the script heirarchially. At the bottom
of the heirarchy are the subroutines within the packages. Double click on a package to
expand it. Subroutines are listed by their full package names.
=item BrkPts
Presents a list of the breakpoints current in use. The pushbutton allows a breakpoint to
be 'disabled' without removing it. Expressions can be applied to the breakpoint. If the
expression evaluates to be 'true'(results in a defined value that is not 0) the debugger
will stop the script. Pressing the 'Goto' button will set the text pane to that file and
line where the breakpoint is set. Pressing the 'Delete' button will delete the breakpoint.
=head1 Menus
=head2 File Menu
=item About...
Presents a dialog box telling you about the version of ptkdb. It recovers
your OS name, version of perl, version of Tk, and some other information
=item Open
Presents a list of files that are part of the invoked perl script. Selecting
a file from this list will present this file in the text window.
=item Save Config...
Requires Data::Dumper. Prompts for a filename to save the configuration to. Saves
the breakpoints, expressions, eval text and window geometry. If the name given as
the default is used and the script is reinvoked, this configuration will be reloaded
automatically.
B<NOTE:> You may find this preferable to using
=item Restore Config...
Requires Data::Dumper. Prompts for a filename to restore a configuration saved with
the "Save Config..." menu item.
=item Goto Line...
Prompts for a line number. Pressing the "Okay" button sends the window to the line number entered.
=item Find Text...
Prompts for text to search for. Options include forward search, backwards search, and regular expression
searching.
=item Quit
Causes the debugger and the target script to exit.
=head2 Control Menu
=item Run
The debugger allows the script to run to the next breakpoint or until the script exits.
=item Run To Here
Runs the debugger until it comes to wherever the insertion cursor in text window
is placed.
=item Set Breakpoint
Sets a breakpoint on the line at the insertion cursor.
=item Clear Breakpoint
Remove a breakpoint on the at the insertion cursor.
=item Clear All Breakpoints
Removes all current breakpoints
=item Step Over
Causes the debugger to step over the next line. If the line
is a subroutine call it steps over the call, stopping when
the subroutine returns.
=item Step In
Causes the debugger to step into the next line. If the line
is a subroutine call it steps into the subroutine, stopping
at the first executable line within the subroutine.
=item Return
Runs the script until it returns from the currently executing
subroutine.
=head2 Data Menu
=item Enter Expression
When an expression is entered in the "Enter Expression:" text box, selecting
this item will enter the expression into the expression list. Each time the
debugger stops this expression will be evaluated and its result updated in
the list window.
=item Delete Expression
Deletes the highlighted expression in the expression window.
=item Delete All Expressions
Delete all expressions in the expression window.
=item Expression Eval Window
Pops up a two pane window. Expressions of virtually unlimitted length
can be entered in the top pane. Pressing the 'Eval' button will cause
the expression to be evaluated and its placed in the lower pane. If
Data::Dumper is available it will be used to format the resulting
text. Undo is enabled for the text in the upper pane. HINT: You can enter multiple expressions by separating them with commas.
=item Use Data::Dumper for Eval Window
Enables or disables the use of Data::Dumper for formatting the results
of expressions in the Eval window.
=head2 Stack Menu
Maintains a list of the current subroutine stack each time the debugger
stops. Selecting an item from this menu will set the text in the code
window to that particular subourtine entry point.
=head2 Bookmarks Menu
Maintains a list of bookmarks. The booksmarks are saved in ~/.ptkdb_bookmarks
=item Add Bookmark
Adds a bookmark to the bookmark list.
=head1 Options
Here is a list of the current active XResources options. Several
of these can be overridden with environmental variables. Resources
can be added to .Xresources or .Xdefaults depending on your X configuration.
To enable these resources you must either restart your X server or
use the xrdb -override resFile command. xfontsel can be used to select
fonts.
/*
* Perl Tk Debugger XResources.
* Note... These resources are subject to change.
*
* Use 'xfontsel' to select different fonts.
*
* Append these resource to ~/.Xdefaults | ~/.Xresources
* and use xrdb -override ~/.Xdefaults | ~/.Xresources
* to activate them.
*/
/* Set Value to se to place scrollbars on the right side of windows
CAUTION: extra whitespace at the end of the line is causing
failures with Tk800.011.
sw -> puts scrollbars on left, se puts scrollars on the right
*/
ptkdb*scrollbars: sw
/* controls where the code pane is oriented, down the left side, or across the top */
/* values can be set to left, right, top, bottom */
ptkdb*codeside: left
/*
* Background color for the balloon
* CAUTION: For certain versions of Tk trailing
* characters after the color produces an error
*/
ptkdb.frame2.frame1.rotext.balloon.background: green
ptkdb.frame2.frame1.rotext.balloon.font: fixed /* Hot Variable Balloon Font */
ptkdb.frame*font: fixed /* Menu Bar */
ptkdb.frame.menubutton.font: fixed /* File menu */
ptkdb.frame2.frame1.rotext.font: fixed /* Code Pane */
ptkdb.notebook.datapage.frame1.hlist.font: fixed /* Expression Notebook Page */
ptkdb.notebook.subspage*font: fixed /* Subroutine Notebook Page */
ptkdb.notebook.brkptspage*entry.font: fixed /* Delete Breakpoint Buttons */
ptkdb.notebook.brkptspage*button.font: fixed /* Breakpoint Expression Entries */
ptkdb.notebook.brkptspage*button1.font: fixed /* Breakpoint Expression Entries */
ptkdb.notebook.brkptspage*checkbutton.font: fixed /* Breakpoint Checkbuttons */
ptkdb.notebook.brkptspage*label.font: fixed /* Breakpoint Checkbuttons */
ptkdb.toplevel.frame.textundo.font: fixed /* Eval Expression Entry Window */
ptkdb.toplevel.frame1.text.font: fixed /* Eval Expression Results Window */
ptkdb.toplevel.button.font: fixed /* "Eval..." Button */
ptkdb.toplevel.button1.font: fixed /* "Clear Eval" Button */
ptkdb.toplevel.button2.font: fixed /* "Clear Results" Button */
ptkdb.toplevel.button3.font: fixed /* "Clear Dismiss" Button */
/*
* Background color for where the debugger has stopped
*/
ptkdb*stopcolor: blue
/*
* Background color for set breakpoints
*/
ptkdb*breaktagcolor*background: yellow
ptkdb*disabledbreaktagcolor*background: white
/*
* Font for where the debugger has stopped
*/
ptkdb*stopfont: -*-fixed-bold-*-*-*-*-*-*-*-*-*-*-*
/*
* Background color for the search tag
*/
ptkdb*searchtagcolor: green
=head1 Environmental Variables
=over 4
=item PTKDB_BRKPT_COLOR
Sets the background color of a set breakpoint
=item PTKDB_DISABLEDBRKPT_COLOR
Sets the background color of a disabled breakpoint
=item PTKDB_CODE_FONT
Sets the font of the Text in the code pane.
=item PTKDB_CODE_SIDE
Sets which side the code pane is packed onto. Defaults to 'left'.
Can be set to 'left', 'right', 'top', 'bottom'.
Overrides the Xresource ptkdb*codeside: I<side>.
=item PTKDB_EXPRESSION_FONT
Sets the font used in the expression notebook page.
=item PTKDB_EVAL_FONT
Sets the font used in the Expression Eval Window
=item PTKDB_EVAL_DUMP_INDENT
Sets the value used for Data::Dumper 'indent' setting. See man Data::Dumper
=item PTKDB_SCROLLBARS_ONRIGHT
A non-zero value Sets the scrollbars of all windows to be on the right side of the window. Useful
for Windows users using ptkdb in an XWindows environment.
=item PTKDB_LINENUMBER_FORMAT
Sets the format of line numbers on the left side of the window. Default value is %05d. useful
if you have a script that contains more than 99999 lines.
=item PTKDB_DISPLAY
Sets the X display that the ptkdb window will appear on when invoked. Useful for debugging CGI
scripts on remote systems.
=item PTKDB_BOOKMARKS_PATH
Sets the path of the bookmarks file. Default is $ENV{'HOME'}/.ptkdb_bookmarks
=item PTKDB_STOP_TAG_COLOR
Sets the color that highlights the line where the debugger is stopped
=back
=head1 FILES
=head2 .ptkdbrc
If this file is present in ~/ or in the directory where perl is invoked the file will
be read and executed as a perl script before the debugger makes its initial stop at startup.
There are several 'api' calls that can be used with such scripts. There is an internal
variable $DB::no_stop_at_start that may be set to non-zero to prevent the debugger from
stopping at the first line of the script. This is useful for debugging CGI scripts.
There is a system ptkdbrc file in $PREFIX/lib/perl5/$VERS/Devel/ptkdbrc
=over 4
=item brkpt($fname, @lines)
Sets breakspoints on the list of lines in $fname. A warning message is generated
if a line is not breakable.
=item condbrkpt($fname, @($line, $expr) )
Sets conditional breakpoints in $fname on pairs of $line and $expr. A warning message is generated
if a line is not breakable. NOTE: the validity of the expression will not be determined until execution
of that particular line.
=item brkonsub(@names)
Sets a breakpoint on each subroutine name listed. A warning message is generated
if a subroutine does not exist. NOTE: for a script with no other packages the default
package is "main::" and the subroutines would be "main::mySubs".
=item brkonsub_regex(@regExprs)
Uses the list of @regExprs as a list of regular expressions to set breakpoints. Sets breakpoints
on every subroutine that matches any of the listed regular expressions.
=item textTagConfigure(tag, ?option?, ?value?)
Allows the user to format the text in the code window. The option
value pairs are the same values as the option for the tagConfigure
method documented in Tk::Text. Currently the following tags are
in effect:
'code' Format for code in the text pane
'stoppt' Format applied to the line where the debugger is currently stopped
'breakableLine' Format applied to line numbers where the code is 'breakable'
'nonbreakableLine' Format applied to line numbers where the code is no breakable
'breaksetLine' Format applied to line numbers were a breakpoint is set
'breakdisabledLine' Format applied to line numbers were a disabled breakpoint is set
'search_tag' Format applied to text when located by a search. Example:
# # Turns off the overstrike on lines that you can't set a breakpoint on # and makes the text color yellow. # textTagConfigure('nonbreakableLine', -overstrike => 0, -foreground => "yellow") ;
- add_exprs(@exprList)
-
Add a list of expressions to the 'Exprs' window. NOTE: use the single quote character \' to prevent the expression from being "evaluated" in the string context. Example: # # Adds the $_ and @_ expressions to the active list # add_exprs('$_', '@_') ;
=head1 NOTES
=head2 Debugging Other perlTk Applications
ptkdb can be used to debug other perlTk applications if some
cautions are observed. Basically, do not click the mouse in the
application's window(s) when you've entered the debugger and do not
click in the debugger's window(s) while the application is running.
Doing either one is not necessarily fatal, but it can confuse things
that are going on and produce unexpected results.
Be aware that most perlTk applications have a central event loop.
User actions, such as mouse clicks, key presses, window exposures,
etc will generate 'events' that the script will process. When
a perlTk application is running, its 'MainLoop' call will accept these
events and then dispatch them to appropriate callbacks associated
with the appropriate widgets.
Ptkdb has its own event loop that runs whenever you've stopped at a
breakpoint and entered the debugger. However, it can accept events
that are generated by other perlTk windows and dispatch their callbacks.
The problem here is that the application is supposed to be 'stopped',
and logically the application should not be able to process events.
A future version of ptkdb will have an extension that will 'filter'
events so that application events are not processed while the
debugger is active, and debugger events will not be processed while
the target script is active.
=head2 Debugging CGI Scripts
One advantage of ptkdb over the builtin debugger(-d) is that it can
be used to debug CGI perl scripts as they run on a web server. Be
sure that that your web server's perl instalation includes Tk.Change your
#! /usr/local/bin/perlto
#! /usr/local/bin/perl -d:ptkdbTIP: You can debug scripts remotely if you're using a unix based server and where you are authoring the script has an Xserver. The Xserver can be another unix workstation, a Macintosh or Win32 platform with an appropriate XWindows package. In your script insert the following BEGIN subroutine:
sub BEGIN {
$ENV{'DISPLAY'} = "myHostname:0.0" ;
}Be sure that your web server has permission to open windows on your Xserver (see the xhost manpage).
Access your web page with your browswer and 'submit' the script as
normal. The ptkdb window should appear on myHostname's monitor. At
this point you can start debugging your script. Be aware that your
browser may timeout waiting for the script to run.To expedite debugging you may want to setup your breakpoints in advance with a .ptkdbrc file and use the $DB::no_stop_at_start variable. NOTE: for debugging web scripts you may have to have the .ptkdbrc file installed in the server account's home directory (~www) or whatever username your webserver is running under. Also try installing a .ptkdbrc file in the same directory as the target script.
KNOWN PROBLEMS
- Breakpoint Controls
-
If the size of the right hand pane is too small the breakpoint controls are not visible. The breakpoints are still there, the window may have to be enlarged in order for them to be visible.
- Balloons and Tk400
-
The Balloons in Tk400 will not work with ptkdb. All other functions are supported, but the Balloons require Tk800 or higher.
AUTHOR
Andrew E. Page, aep@world.std.com
ACKNOWLEDGEMENTS
Matthew Persico For suggestions, and beta testing.
3 POD Errors
The following errors were encountered while parsing the POD:
- Around line 522:
'=item' outside of any '=over'
- Around line 609:
'=item' outside of any '=over'
- Around line 620:
You forgot a '=back' before '=head1'