[python] cycle import style

[alexpw]

Python import statements can be written in a few different styles. Initially, I wanted the equivalent of toggle_multiline() for import_from_statements between "inline" and "expand" (see Formats), but certain style guides prefer a "single" style (one import per line). There are other preferences, like whether a multi-line statement is wrapped in parentheses or uses \ for line continuation, and it also needs to account for a max line_length. So I wrote up something custom to cycle between them, and made it configurable.

Formats

import_statement

• "single"

import json
import xml

• "inline"

import json, xml

import_from_statement

• "single"

from json import loads
from json import dumps

• "inline"

from json import loads, dumps

• "expand"

from json import (
    loads,
    dumps,
)

Siblings

cycle_import() will look for and include siblings that are adjacent to the node performing the action. Siblings have the same :type() and import from the same module/package. This is what enables the "single" format to participate in cycling. For example, going from "single" to "inline":

from json import loads
from json import dumps

from json import loads, dumps

isn't possible without being able to combine* the two.

*Implementation Note:

There is no appropriate parent to act as a target node that could provide the correct node:range() for init.lua:replace_node(), so in this case, it creates a table in make_target_node() that responds to :range() with the correct start/end positions (and more, see comments).

[CKolkey]

Just go ahead and request a review when you feel its ready :)

[alexpw]

Thanks, I thought it was ready, but the format detection needs more testing / thought to stabilize.

I can't add reviewers, but I can use the draft status and mark it "Ready for review" soon (tm).

[CKolkey]

You can't? Huh, wonder what I need to set to enable that. Until then, draft is fine :)

[alexpw]

Sorry for a massive diff. I moved* code, so turning off whitespace in the PR tab will hopefully help (Gear -> "Hide Whitespace").

*python.lua had grown too big, so I moved the if/else code to python/conditional.lua and created a python/node_utils.lua to share node related functions. I had fun with an approach for iterating over nodes that might've turned out well.