NAME¶
Devel::ptkdb - Perl debugger using a Tk GUI
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
SYNOPSIS¶
To debug a script using ptkdb invoke perl like this:
perl -d:ptkdb myscript.pl
Usage¶
perl -d:ptkdb myscript.pl
Code Pane¶
- 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).
- 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. 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.
Notebook Pane¶
- Exprs
-
This is a list of expressions that are evaluated each time the
debugger stops. The results of the expresssion are presented
hierarchically 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.
- 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.
- 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.
- 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
- 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.
- 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
- Restore Config...
- Requires Data::Dumper. Prompts for a filename to restore a configuration
saved with the "Save Config..." menu 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.
- Quit
-
Causes the debugger and the target script to exit.
- 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.
- Set Breakpoint
- Sets a breakpoint on the line at the insertion cursor. item Clear
Breakpoint
Remove a breakpoint on the at the insertion cursor.
- Clear All Breakpoints
- Removes all current breakpoints
- 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.
- 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.
- Return
- Runs the script until it returns from the currently executing
subroutine.
- Restart
- Saves the breakpoints and expressions in a temporary file and restarts the
script from the beginning. CAUTION: This feature will not work properly
with debugging of CGI Scripts.
- Stop On Warning
- When "-w" is enabled the debugger will stop when warnings such
as, "Use of uninitialized value at undef_warn.pl line N" are
encountered. The debugger will stop on the NEXT line of execution since
the error can't be detected until the current line has executed.
This feature can be turned on at startup by adding:
$DB::ptkdb::stop_on_warning = 1 ;
to a .ptkdbrc file
- 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.
- Delete Expression
-
Deletes the highlighted expression in the expression window.
- Delete All Expressions
-
Delete all expressions in the expression window.
- 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.
- Use Data::Dumper for Eval Window
- Enables or disables the use of Data::Dumper for formatting the results of
expressions in the Eval window.
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.
Maintains a list of bookmarks. The booksmarks are saved in ~/.ptkdb_bookmarks
- Add Bookmark
- Adds a bookmark to the bookmark list.
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
Environmental Variables¶
- PTKDB_BRKPT_COLOR
- Sets the background color of a set breakpoint
- PTKDB_DISABLEDBRKPT_COLOR
- Sets the background color of a disabled breakpoint
- PTKDB_CODE_FONT
- Sets the font of the Text in the code pane.
- 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: side.
- PTKDB_EXPRESSION_FONT
-
Sets the font used in the expression notebook page.
- PTKDB_EVAL_FONT
-
Sets the font used in the Expression Eval Window
- PTKDB_EVAL_DUMP_INDENT
-
Sets the value used for Data::Dumper 'indent' setting. See man Data::Dumper
- 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
X environment.
- 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.
- PTKDB_DISPLAY
- Sets the X display that the ptkdb window will appear on when invoked.
Useful for debugging CGI scripts on remote systems.
- PTKDB_BOOKMARKS_PATH
- Sets the path of the bookmarks file. Default is
$ENV{'HOME'}/.ptkdb_bookmarks
- PTKDB_STOP_TAG_COLOR
- Sets the color that highlights the line where the debugger is stopped
FILES¶
.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
- brkpt($fname, @lines)
- Sets breakspoints on the list of lines in $fname. A warning message is
generated if a line is not breakable.
- condbrkpt($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.
- 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".
- 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.
- 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 $_ and @_ expressions to the active list
#
add_exprs('$_', '@_') ;
NOTES¶
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.
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/perl
to
#! /usr/local/bin/perl -d:ptkdb
TIP: You can debug scripts remotely if you're using a unix based Xserver 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 X 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, aepage@users.sourceforge.net
ACKNOWLEDGEMENTS¶
Matthew Persico For suggestions, and beta testing.
BUG REPORTING¶
Please report bugs through the following URL:
http://sourceforge.net/tracker/?atid=437609&group_id=43854&func=browse