lambda (and reduce) are valuable

[Paul Rubin]

Chris Mellon <arkanes at gmail.com> writes:
> As someone who does a tremendous amount of event-driven GUI
> programming, I'd like to take a moment to speak out against people
> using us as a testament to the virtues of lamda. Event handlers are
> the most important part of event-driven code, and  making them real
> functions with real names is crucial to maintainable code. The only
> reason to ever use a lamdba in Python is because you don't want to
> give a function a name, and that is just not a compelling use case for
> GUI events.

I thought stuff like the following was idiomatic in GUI programming.
Do you really want separate names for all those callbacks?

# generate calculator keypad buttons
Button(label='7', command=lambda: user_pressed(7)).grid(column=1, row=1)
Button(label='8', command=lambda: user_pressed(8)).grid(column=2, row=1)
Button(label='9', command=lambda: user_pressed(9)).grid(column=3, row=1)

Button(label='4', command=lambda: user_pressed(4)).grid(column=1, row=2)
Button(label='5', command=lambda: user_pressed(5)).grid(column=2, row=2)
Button(label='6', command=lambda: user_pressed(6)).grid(column=3, row=2)
...