Support formatting code provided via stdin

[vlcinsky]

yapf has very similar command line interface as pyformat but provides one additional one: pass a code via stdin and print result on stdout.

Such a feature makes it very easy for integrating e.g. into vim editor by adding following line into .vimrc file:

autocmd FileType python setlocal equalprg=yapf

and user may format the code of whole file:

gg=G

or in visual mode (multiple lines selected):

=

pyformat does not accept file on stdin thus it is not possible to use it in the same style. Adding such feature to pyformat would make use simpler.

[viniciusban]

@vlcinsky you can use something like this:

1. Create a file called my-equalprg and give execution status to it (chmod +x my-equalprg):

#!/usr/bin/env bash

TMPFILE=$(mktemp).py

cat - > $TMPFILE \
    && pyformat --in-place $TMPFILE
cat $TMPFILE

2. Inside your .vimrc file:

autocmd FileType python setlocal equalprg=my-equalprg

The gotcha is that equalprg setting writes to stdout and expects result in stdin.

[vlcinsky]

@viniciusban thanks for the workaround.

What gotcha do you mean? Encoding troubles?

[viniciusban]

Sorry, I didn't express myself correctly.

It's not a "gotcha", but a characteristic. As equalprg works with stdin and stdout we can write our own filter and do whatever we need.

Actually my current filter runs some utilities in a pipeline. The last one is yapf, btw. ;-)