Print neovim api-info using python 3

Question

I get a human readable list of api functions using

:new|put =map(api_info().functions, 'v:val.name')

in neovim as suggested on https://neovim.io/doc/user/msgpack_rpc.html.

Problem is, this doesn't show the method signatures like the perl example on http://techblog.babyl.ca/entry/neovim-way-to-go.

#!/usr/bin/env perl 
use Neovim::RPC;
my $rpc = Neovim::RPC->new->api->print_command;

yielding

...
vim_replace_termcodes ( String str, Boolean from_part, Boolean do_lt, Boolean special ) -> String
...
vim_set_current_line ( String line ) -> void
...

But: I don't use perl, I want to use python and want to print a formatted dump of the neovim api as suggested in https://neovim.io/doc/user/msgpack_rpc.html.

nvim --api-info | python -c 'import msgpack, sys, yaml; print( yaml.dump(msgpack.unpackb(sys.stdin.read())) )'

However, I get the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/info/w/sc/lib/python3.4/codecs.py", line 319, in decode
     (result, consumed) = self._buffer_decode(data, self.errors, final)
 UnicodeDecodeError: 'utf-8' codec can't decode byte 0x83 in position 0: invalid start byte

Trying to isolate the error, I did

nvim --api-info | python -c 'import sys; print( sys.stdin.read() )'

resulting in the same error as above.

I think the reason is me using python 3.4 not python 2.7. How do you correctly code this in python 3.4?

Moreover, there seems to be a discrepancy between the api function and the python implementation, e.g. if you want to access the api function vim_set_current_line, you need to write

from neovim import attach
v = attach('socket', path='/tmp/nvim')
v.api.set_current_line("zzzz")

and not v.api.vim_set_current_line("zzzz").

Is there a way to find out about "pythonic" api-functions (apart from consulting https://github.com/neovim/python-client/tree/master/neovim/api) ?

Answer 1

In Python 3, there's an emphasis on unicode strings. sys.stdin has a buffer attribute that lets you get to the underlying byte buffer, but Python 2's sys.stdin does not. If you want something that'll work for both versions, you can use the -u command line argument, as well as getattr():

nvim --api-info | python -u -c 'import sys,msgpack; print(msgpack.unpackb(getattr(sys.stdin, "buffer", sys.stdin).read()))'

The relevant bit is:

getattr(sys.stdin, "buffer", sys.stdin).read()

If you're more comfortable using Neovim to work with the text, there is also the api_info() function in Neovim.

Answer 2

For python 3 use this:

nvim --api-info | python -c 'import msgpack, sys, yaml; print( yaml.dump(msgpack.unpackb(sys.stdin.buffer.read(), raw=False)))' | less