I don’t understand what you mean—it doesn’t really matter how many characters or columns you’re indented, and can’t you discern depth visually in the same way regardless of typeface?
I've been using DejaVu Sans (proportional) for programming (including Python) for the last few months, and found it very easy to get used to.
There are just a few glyphs that could be adjusted to line up better (closing braces in JS/PHP are a few px off), or in the case of quotation marks, two single quotes render the same as one double quote.
I've started editing DejaVu (it's OSS) to correct these small number of issues, I don't think they are insurmountable.
Well I'm not sure that it's actually a problem in practice but with a W taking up two ' ' spaces I can imagine a scenario where you over correct and end up in the wrong level.
No, it doesn’t. Your indentation level matters, but provided your indentation is consistent, it doesn’t matter whether you use tabs or spaces, and the notion of “column” isn’t relevant to proportional-width fonts. If you’re worried about invalid indentation hiding from you, don’t use spaces for indentation with a proportional font—it doesn’t make sense anyway.
It matters more when you've got a statement broken over multiple lines. If you've got a function which takes a lot of arguments for example, lining them all up vertically can make the code a lot easier to read. This can be difficult or impossible to do with a proportional width font (and would almost certainly look very strange to anyone else looking at the code in a fixed-width font).
That's understandable. I agree that tabs would work much better than spaces with a proportional font. However, in the case of Python PEP 8 states that you should use 4 spaces. Not doing so will make it very hard to collaborate with other devs.
It's not that I think that proportional fonts couldn't work (even with python) It's just that I have concern about visually assessing indentation. Maybe it's time I try one and find out.
