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Keyboard replacement with stack trace

version (1.28 KB) by Romesh
Display a stack trace showing where keyboard was used


Updated 20 Feb 2013

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The 'keyboard' command is great for debugging, but if you have multiple instances of keyboard, it is very difficult to tell which one is being called. This complicates debugging somewhat.

kdb() is a drop-in replacement for keyboard, and it shows a stack trace, preview of the next line to be executed, and a hyperlink to that line of code. For example, if foo() calls bar() calls baz() and we have a 'keyboard' command in baz(), the user sees

>> foo

whereas with kdb() the user sees

>> foo

baz:2 << bar:2 << foo:3
3 y = x+2;

The '3' is a hyperlink to line 3 of baz.m, and depending on settings the Matlab editor may automatically open to the appropriate kdb() statement. The only caveat is that unlike keyboard, kdb() cannot be the last statement in the function.

Cite As

Romesh (2020). Keyboard replacement with stack trace (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (2)


Thanks for the suggestion, I am also a big fan of eliminating calls to eval() wherever possible. I've submitted an updated version incorporating both your changes

per isakson

Your idea is very good. I've never been comfortable with KEYBOARD. To me your function provides a "persistent" break-point. However, I have modified the code to handle functions in packages.

stk = dbstack('-completenames');
dbstop( 'in', stk(2).file, 'at', num2str( stk(2).line+1 ) )


Updated with suggestions from Per Isakson to support packages

MATLAB Release Compatibility
Created with R2011b
Compatible with any release
Platform Compatibility
Windows macOS Linux