Full integer (, float and number) type support

[geyang]

Hi @dgillis,

I found this article helpful as a guide for a list of python format syntaxes:

https://pyformat.info | Using string.format() for great good!

Right now it seems the following are missing:

"{year:02d".format({year})

Also this is not allowed with python string format:

'{year:.2d}'.format(year=2018)
# gives `precision` is not allow with integer format.

This is surprisingly allowed with string type

'{year:.2}'.format(year="2019")