Black on selection

black_selection.sh

#!/usr/bin/env bash

set -x

black=$1
input_file=$2
start_line=$3
end_line=$4

# Read selected lines and write to tmpfile
selection=$(sed -n "$start_line, $end_line p; $(($end_line+1)) q" < $input_file)
tmpfile=$(mktemp)
echo "$selection" > "$tmpfile"

# Apply Black formatting to tmpfile
$black $tmpfile

# Delete original lines from file
sed -i "" "$start_line,$end_line d" $input_file

# And insert newly formatted lines
sed -i "" "$(($start_line-1)) r $tmpfile" $input_file

You are a saviour @BasPH ! I found your article on partial formatting with Black and it was very helpful! I guess I'll finally start using Pycharm after this.

Hello, I really appreciate for your cool and nice work!

I made a python version to utilize your 'partial black" in Windows OS and complied it to exe.
https://gist.github.com/imcomking/04d8ce30b6ac444e413392ab675b1d2c

Great script! thank you @BasPH

By the way < $input_file part in line 11 is missing in the script in your post.

thanks for the script. it's a lifesaver

Really cool, it's exactly what I was looking for.

I think it would be good to also add set -e to the script so that if black fails, we don't risk overwriting anything

I think the deletion of the original lines deletes one extra line. It should delete until "$end_line - 1"

Any idea about this? @BasPH

error: cannot format /var/folders/bf/5_lvbmr539v26pk7qbrdrnd5drn_gd/T/tmp.8S3OqTW5: cannot use --safe with this file; failed to parse source file AST: unexpected indent (<unknown>, line 1)
This could be caused by running Black with an older Python version that does not support new syntax used in your source file.