lsp: Add more configuration for handlers

[tjdevries]

If someone wants to take this over, this is pretty similar to the concept that we were going for in #12966

This will allow you to more easily manage / re-use internal logic for doing location handling, without having to copy and paste.

vim.lsp.handlers["textDocument/definition"] = vim.lsp.with(
  vim.lsp.handlers.location, {
    location_callback = function(location)
      vim.cmd [[vsplit]]
      vim.lsp.util.jump_to_location(location)
    end
  }
)

[neovim-discourse]

This pull request has been mentioned on Neovim Discourse. There might be relevant details there:

https://neovim.discourse.group/t/how-to-customize-lsp-actions/349/5

[jlesquembre]

Found this issue while trying to configure the jump-to-definition handler. With this approach, I guess that if we want to have multiple mappings (e.g.: open definition in split and vsplit), it would look something like this:

function open_definition_vsplit ()
  local handler = vim.lsp.with(
    vim.lsp.handlers.location, {
      location_callback = function(location)
        vim.cmd [[vsplit]]
        vim.lsp.util.jump_to_location(location)
      end
    }

  local params = vim.lsp.util.make_position_params()
  vim.lsp.buf_request(0, 'textDocument/definition', params, handler)
end

vim.api.nvim_set_keymap("n", "gdv", "<cmd>lua open_definition_vsplit()<cr>", opts)

[mjlbach]

@tjdevries What needs to get done for this to get merged? I'll take it over.

[tjdevries]

Probably just add a test and fix conflicts?

[mjlbach]

This is pretty out of date, closing as we've changed a lot of this code now.

[mmoya]

Found this issue while trying to configure the jump-to-definition handler. With this approach, I guess that if we want to have multiple mappings (e.g.: open definition in split and vsplit), it would look something like this:
...

@jlesquembre do you have by any chance a 2022 version of your snippet?

[justinmk]

I am looking at reviving some form of this. #22598