Consider where "point/cursor" should end up

[kootenpv]

Maybe it could be a nice addition when it becomes possible to add "cursor_position" and then black could return where it should end up after processing

[ambv]

Is this about the Vim plugin?

[kootenpv]

@ambv It counts for any editor plugin.

[ambv]

Oh, you'd want black the command to accept --cursor-line= and --cursor-column= arguments and return new ones with the output?

[kootenpv]

@ambv Exactly! Given that it uses the AST, it should be possible to implement.

[kootenpv]

Any new ideas on this? Perhaps it is possible for each action to keep track of (position_of_change, added_number_of_chars) (the latter being positive or minus).

At the end, the new cursor position can be computed from applying the counts sequentially (bearing in mind not to count the changes past the initially provided char position).

I think returning an integer for the nth character might work, does not have to be line+column (I think in e.g. both emacs and vim it is easy to just jump to the nth char).

[vastus]

Maybe the vim plugin could use this information as well. Currently the plugin errors if the cursor is at EOF and reformatting cuts down on the original line number count of the file before formatting.

Here's an example (| denotes cursor position):

in:

[
    42
]|

running :Black produces the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<string>", line 76, in Black
vim.error: cursor position outside buffer

after hitting return:

|[42]