README file for TDebug, an alternative tcl/tk-debugger. $Id: README,v 5.0 1995/05/02 06:32:04 gs Exp $ This file documents TDebug Version 1.0. It was written with emacs using Jamie Lokier's folding mode That's what the funny {{{ marks are there for. Please send comments, suggestions, bug-reports etc to schmid@fb3-s7.math.tu-berlin.de Any feedback is welcome! {{{ Disclaimer This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. }}} {{{ Files README this file TdChoose.tcl the TDebug front end TdDebug.tcl the debugger ChangeLog development history }}} {{{ General TDebug uses a different approach than any other debugger I've seen for Tcl/Tk. If you know the emacs-lisp debugger `edebug' the following may seem familiar. TDebug is solely based on Tcl/Tk, there is no C-code, which makes it very easy to install. It works by parsing and redefining Tcl/Tk-procs, inserting calls to `td_eval' at certain points, which takes care of the display, stepping, breakpoints, variables etc. The advantages are that TDebug knows which statement in what proc is currently being executed and can give visual feedback by highlighting it. All currently accessible variables and their values are displayed as well. Code can be evaluated in the context of the current proc. Breakpoints can be set and deleted with the mouse. Unfortunately there are back-draws to this approach. Preparation of large procs is slow and due to Tcl's dynamic nature there is no guarantee, that a proc can be prepared at all. This problem has been alleviated somewhat with the introduction of partial preparation of procs. There is still no possibility to get at code running in global context, but I'm not sure if that would be useful anyway. }}} {{{ News New since version 0.9 * compatibility with Tk 4.0 * chooser layout changed * Name program to debug on the command line New since version 0.3 * display any proc without preparing it first * partial preparing and restoring * detach from applications on exit * faster parsing (thanks to Alessandro Rubini) * parsing bugs fixed, should now parse any proc * cline extensions included for `Eval:' line * can eval at global level * optionally hide global variables and arrays * optionally hide tk_* procs and others * chooser now recognizes if procs are redefined * a LOT more configuration options: * Geometry for all toplevels * Style of tags in listing }}} {{{ Installation Make sure you keep TdChoose.tcl and TdDebug.tcl in the same directory. Edit the first line of TdChoose.tcl to reflect the location of your `wish' and make sure TdChoose.tcl is executable. There are really two versions of TDebug, but contained in one source. Under normal circumstances, TdChoose.tcl, the TDebug frontend, provides a standalone application that talks to other Tcl/Tk-based applications via `send'. To debug a running application, TDebug sends a `source TdDebug.tcl' to it, making the debugger available. You can then choose procs to prepare for debugging. Depending on your installation the Tk command `send' may not work for you. In this case you should create a configuration file called .tdebugrc in your home directory that contains the line set td_priv(send) 0 If you are running on a black and white screen, you should put something along the following lines into the ~/.tdebugrc file. set td_priv(preparedtag) {-fgstipple gray50} set td_priv(activetag) {-background black -foreground white \ -fgstipple gray50} set td_priv(breaktag) {-background black -foreground white} See the Configuration section for additional things to put into this file. }}} {{{ Usage If TDebug is installed correctly you can start it by running TdChoose. If you can use `send', this will bring up the Chooser which lets you switch between all running Tk applications. Caveat: Due to incompatibilities in the `send' command of Tk versions before and after 4.0, you can only debug applications running with an interpreter of the same generation as the Debugger. TDebug cannot detect whether another interpreter is compatible or not until it tries to send a command to it. If you can't use `send', give the program you wish to debug as argument on the command line, e.g. TdChoose.tcl test.tcl This will start your application and the debugger in the same interpreter. Running TDebug this way will always disable the use of the send command. The Chooser: Th TDebug chooser has three parts. At the top the current interpreter is shown. If you are using send you can use the `+' button to pop up a menu and select a different interpreter. In the main section there are two listboxes. The first one shows all procs that are defined in the current interpreter. By clicking the left mouse button on a proc name, the proc gets prepared for debugging and its name is moved to the second listbox. Clicking a name in the second listbox returns a proc to its normal state. You can control whether TDebug specific procs and Tk specific procs are displayed in the listbox or not. See the Configuration section. Press the right mouse button on a proc in either listbox to get its program code displayed in the main debugger window. The three buttons at the bottom let you force a rescan of the available procs, pop up the debugger window or exit TDebug. Exiting from TDebug doesn't terminate the running application, it merely detaches from all interpreters, restoring all prepared procs to their unmodified state. The Debugger: The debugger window is divided into the main region with the name of the current proc, a listing in which the expression just executed is highlighted, the result of this execution and the currently available variables and their values, an entry to eval expressions in the context of the current proc and some controls for the state of the debugger. A proc listing displayed in the main region will have a darker background on all lines that have been prepared. You can prepare or restore additional lines by selecting a region (, standard selection) and choosing `Prepare' or `Restore' from the Selection menu (or by pressing ^P or ^R). `Prepare' and `Restore' try to be smart about what you intend to do. If you select just a single word (plus some optional whitespace) it will be interpreted as the name of a proc to prepare or restore. Otherwise, if the selection is owned by the listing, the corresponding lines will be used. Be careful with partial prepare or restore! If you prepare random lines inside a `switch' or `bind' expression, you may get surprising results on execution, because the parser doesn't know about the surrounding expression and can't try to prevent problems. There are seven possible debugger states, one for each button and an `idle' or `waiting' state when no button is active. The others are: Stop - Stop after next expression, used to get out of slow/fast/nonstop mode. Next - Execute one expression, then revert to idle. Slow - Execute until end of proc, stopping at breakpoints or when the state changes to stop. After each execution, stop for `delay' milliseconds. The delay can be changed with the `+' and `-' buttons. Fast - Execute until end of proc, stopping at breakpoints. Nonstop - Execute until end of proc without stopping at breakpoints or updating the display. Break - Terminate execution of current proc. The menus should be obvious (Sorry better docs MAY be available some day:-). Closing the debugger doesn't quit it, it only does `wm withdraw'. The debugger window will pop up the next time a prepared proc is called. Breakpoints: To set/unset a breakpoint, double-click inside the listing. The breakpoint will be set at the innermost available expression that contains the position of the click. There's no support for conditional or counted breakpoints yet. The `Eval: ' entry supports a simple history mechanism available via the and keys. If you evaluate a command while stepping through a proc, the command will be evaluated in the context of the proc, otherwise at global level. The result will be displayed in the result field. This entry is useful for a lot of things, but especially to get access to variables outside the current scope. Try entering the line `global td_priv' and watch the `Variables' box (with global and array variables enabled of course). }}} {{{ Configuration You can customize TDebug by setting up a file named .tdebugrc in your home directory. The following variables have special effects: Relevant for the Debugger window: Variable Value Effect ----------------------------------------------------------------------- td_priv(wrap) none Don't wrap listing of current proc word Word-wrap listing td_priv(wrapback) none Don't wrap backtrace word Word-wrap backtrace td_priv(fullnames) 1 Display full widget names 0 Display the last part only td_priv(update) slow Always update variables fast Update variables in idle state only td_priv(detail) low Don't check for subexpressions when preparing procs high Do check for subexpressions td_priv(delay) Delay in milliseconds used with slow stepping (100-1500) td_priv(globalvars) 1 Display global variables accessible from current proc 0 Don't display global variables td_priv(arrayvars) 1 Display array variables similar to parray 0 Don't display arrays (they take too much space) td_priv(scrollbarside) left Place all scrollbars at the left side right Place all scrollbars at the right side td_priv(constrainscroll) 1 Don't scroll after last line in listing 0 Normal scrolling td_priv(height) Height of proc listing td_priv(listwidth) Width of proc listing td_priv(varwidth) Width of variable display td_priv(geometry) Geometry of Debugger window. Use for position only! td_priv(preparedtag) tag style for prepared lines td_priv(activetag) tag style for currently active expression td_priv(breaktag) tag style for breakpoints Tag styles are used for .widget tag configure ... For example "-background red -foreground blue" etc. td_priv(tagpriority) priority of tags, lowest priority first. Legal tag values are (default priority): prepared sel active break td_priv(useblt) 0 Don't use BLT, even if available If unset, use BLT if it is available Relevant for the Chooser window: Variable Value Effect ----------------------------------------------------------------------- td_priv(send) 0 Can't use send 1 Can use it td_priv(scrollbarside) left Place all scrollbars at the left side right Place all scrollbars at the right side td_priv(constrainscroll) 1 Don't scroll after last line in listing 0 Normal scrolling td_priv(chooseheight) Height of chooser box td_priv(choosewidth) Width of chooser box td_priv(choosegeometry) Geometry of Choose window. Use for position only! td_priv(hideownprocs) 1 Don't display procs belonging to TDebug 0 Display those procs (be careful!) td_priv(hidetkprocs) 1 Don't display procs belonging to Tk, i.e. tk_*, auto_* and unknown. 0 Display those procs td_priv(debugdir) Set to the directory containing TdDebug.tcl. Not necessary if it is the same as TdChoose.tcl. Relevant for the Backtrace window: Variable Value Effect ----------------------------------------------------------------------- td_priv(backtraceheight) Height of backtrace td_priv(backtracewidth) Width of backtrace td_priv(backtracegeometry) Geometry of Backtrace window. Use for position only! Relevant for the ErrorTrace window: Variable Value Effect ----------------------------------------------------------------------- td_priv(errorheight) Height of error trace td_priv(errorwidth) Width of error trace td_priv(errorgeometry) Geometry of ErrorTrace window. Use for position only! Relevant for the WidgetHierarchy window: Variable Value Effect ----------------------------------------------------------------------- td_priv(widgetsheight) Height of hierarchy td_priv(widgetswidth) Width of hierarchy td_priv(widgetsgeometry) Geometry of WidgetHierarchy window. Use for position only! }}} {{{ Todo TDebug is nearing version 1.0. Nevertheless there are quite a few things left to do, including Bug/Feature-fixes as well as documentation and real development: * Better parsing. Switch statements don't work well yet. * Conditional breakpoints, watchpoints. * Better documentation !!!! * A real Help button, not just a dummy. * Make a dialog to display widget information - selectable from hierarchy Maybe like TkInspekt ? * Support for [incr tcl] How about a class browser ? }}} {{{ Bugs Some expressions don't parse well. This can't be fixed (I think) without an unacceptable increase in parsing time. The following known problems exist: switch expressions of the type switch $var { 1 { do_something } 2 { do_something_else} } will fail for case 2. A multiple line expr without `\' will fail: if {$var == 1 \ || $var == 2} {...} will work whereas if {$var == 1 || $var == 2} {...} will fail. If you run into such problems, restore the offending lines via the selection mechanism and try again. }}} {{{ Credits Thanks to: John Ousterhout for Tcl/Tk Alessandro Rubini for numerous good ideas and speedups for parsing Renzo Lazzarato fixed the td_priv(debugdir) problem }}} {{{ Emacs local variables Local variables: mode: text folded-file: t End: }}}