Neovim completion using ripgrep

If you're using nvim-cmp but lsp support isn't all you'd hoped - a few tailored ripgrep searches may well do the trick. The plugin allows you to setup regex searches via ripgrep to flow into the nvim-cmp completion engine.

Installation

There are many ways to do this. Here's an exmaple using lazy.nvim

{
  "hrsh7th/nvim-cmp",
    dependencies = {
      "hrsh7th/cmp-nvim-lsp",
      "kizza/cmp-rg-lsp",
    },
    ...
  }
},

Usage

Include "rg-lsp" amongst your completion sources...

local cmp = require'cmp'

cmp.setup({
  ...
  sources = cmp.config.sources({
    { name = "nvim_lsp" },
    {
      name = "rg_lsp",
      patterns = {
        require("cmp-rg-lsp.builtins").ruby, -- Include inbuilt pattern collections
        {
          filetype = { "ruby" }, -- Only run this for given filetypes
          kind = cmp.lsp.CompletionItemKind.Property,  -- How result is displayed
          pattern = '^#\\s*(\\w*%s\\w+)+\\s+:', -- The regex to run over your codebase
          match = 1, -- The match index (given multiple regex groups)
        }
      }
    },
  })
  ...
}

Example regex

The compeltion word being typed is substituted into the pattern via the %s character. So to match method declarations within a ruby codebase (for example)

def available_times
  ...
end

we can use...

  pattern = '^\\s*def\\s+(\\w*%s\\w+(\\?|!)?)',

with the following breif explanation

^ start of line
\\s* possible prefixed white space
def\\s+ "def" with space after it
( open the matching group
\\w* perhapa a prefix of other text (ie. look for a partial match)
%s the completion text
(\\?|!)? possibly ending with a ! or a ?
) close the matching group

All wrapped up to be

{
  filetype = { "ruby" }, -- Only run this for given filetypes
  kind = cmp.lsp.CompletionItemKind.Method,  -- We're matching methods
  pattern = '^\\s*def\\s+(\\w*%s\\w+(\\?|!)?)', -- The pattern above
  match = 1, -- We're matching the first group
}