feat(lint): let attributes be functions

[MoritzBoehme]

This change is prompted by a change in the python linter ruff. The json output has changed a bit and the severity no longer simply parsed. Example:

import random

[
  {
    "code": "F401",
    "message": "`random` imported but unused",
    "fix": {
      "applicability": "Unspecified",
      "message": "Remove unused import: `random`",
      "edits": [
        {
          "content": "",
          "location": {
            "row": 1,
            "column": 1
          },
          "end_location": {
            "row": 2,
            "column": 1
          }
        }
      ]
    },
    "location": {
      "row": 1,
      "column": 8
    },
    "end_location": {
      "row": 1,
      "column": 14
    },
    "filename": "/tmp/tmp.zV0Bmo7zZd/tmp.py",
    "noqa_row": 1
  }
]

By making all attributes in from_json a function or a key to the json message table, we can again extract the severity.
The new ruff config would be something like this:

{
  cmd = "ruff",
  args = {
    "-n",
    "-e",
    "--format",
    "json",
    "-",
    "--stdin-filename",
  },
  fname = true,
  stdin = true,
  parse = lint.from_json({
    attributes = {
      severity = function(js)
        return string.sub(js["code"], 1, 1) -- first character
      end,
      lnum = function(js)
        return js["location"]["row"]
      end,
      col = function(js)
        return js["location"]["column"]
      end,
    },
    severities = {
      E = lint.severities.error, -- pycodestyle errors
      W = lint.severities.warning, -- pycodestyle warnings
      F = lint.severities.info, -- pyflakes
      A = lint.severities.info, -- flake8-builtins
      B = lint.severities.warning, -- flake8-bugbear
      C = lint.severities.warning, -- flake8-comprehensions
      T = lint.severities.info, -- flake8-print
      U = lint.severities.info, -- pyupgrade
      D = lint.severities.info, -- pydocstyle
      M = lint.severities.into, -- Meta
    },
    source = "ruff",
  }),
}

I have tested this on my machine, but as this is part of https://github.com/nvimdev/guard-collection I didn't add or alter any test in this repo. Let me know what you think about this change :)

[xiaoshihou514]

Maybe separate the logic into a function since it appears many times

[MoritzBoehme]

Yeah, good call 👍

[xiaoshihou514]

Seems great! Makes api more consistent