exclamation mark not correctly handled

[ftalbrecht]

I am using

pip freeze | grep jupytext
jupytext==1.2.4

and the following MWE file (say Untitled.md)

try:
    !echo jo
except:
    pass

(which is intended to be run as a jupyter notebook inside a jupyter server using the jupytext extension, which works well, btw.) is not correctly converted to python on the command line. I.e., the output of

jupytext --to py Untitled.ipynb

yields the following Untitled.py:

cat Untitled.py 
# ---
# jupyter:
#   jupytext:
#     text_representation:
#       extension: .py
#       format_name: light
#       format_version: '1.4'
#       jupytext_version: 1.2.4
#   kernelspec:
#     display_name: Python 3
#     language: python
#     name: python3
# ---

try:
    !echo jo
except:
    pass

I would expect the !echo jo statement to be commented out, but the presence of the try: seems to hinder this...
This is related to #149, but not the same.

[mwouts]

Hello @ftalbrecht , thanks for reporting this.

That should be easy to fix... we just need to allow spaces before the exclamation mark in this regular expression:

jupytext/jupytext/magics.py

Lines 23 to 24 in b2c0670

	# Commands starting with a question or exclamation mark have to be escaped
	_PYTHON_HELP_OR_BASH_CMD = re.compile(r"^(# |#)*(\?|!)\s*[A-Za-z]")

i.e. probably replace it with

_PYTHON_HELP_OR_BASH_CMD = re.compile(r"^(# |#)*\s*(\?|!)\s*[A-Za-z]")

But then, is the empty try statement valid in Python?

[mwouts]

@ftalbrecht , I'll do the fix. Just to mention, when the !echo command is commented out, the Python code is not valid any more, so you will have to add a pass to make the Python representation valid:

[ftalbrecht]

@ftalbrecht , I'll do the fix. Just to mention, when the !echo command is commented out, the Python code is not valid any more, so you will have to add a pass to make the Python representation valid:

Sure, that was just meant to be the smallest failing example I could think of. Thx for the fix!

[mwouts]

I am having an issue with

if True:
    !rm file 1
    # !rm file 2

which is not stable over round trip. Preserve the indentation when commenting out should help... let me see...