Python pudb
From wikinotes
pudb is a gui debugger.
Watch a Variable
watching a variable in pudb enters it into the GUI on the top right. Breakpoints are not added, it simply displays whether the expression is true or false as you step through the code.
### Code
a = 0
a = 1
a = 2
a = 3
a = 4
### pudb watch expression
a > 2
### Action
# a > 2 will display false until the condition is met,
# at which point it will say 'True'