feat: add completion support for coq_nvim (#258)

Author: TheLeoP

README.md

@@ -146,6 +146,12 @@ require('blink.cmp').setup({
 })
 ```
 
+## coq_nvim
+
+```lua
+require("render-markdown.integ.coq").setup()
+```
+
 # Setup
 
 Checkout the [Wiki](https://github.com/MeanderingProgrammer/render-markdown.nvim/wiki)

lua/render-markdown/integ/coq.lua

@@ -0,0 +1,68 @@
+local source = require('render-markdown.integ.source')
+
+local M = {}
+
+---@class coq.Args
+---@field pos {[1]: integer, [2]:integer}
+---@field line string
+
+---@class coq.CallbackArgs
+---@field isIncomplete boolean
+---@field items vim.lsp.CompletionResult
+
+---@class coq.Source
+---@field name string
+---@field fn fun(args: coq.Args, callback: fun(args?: coq.CallbackArgs)): fun()|nil
+
+---@alias coq.Sources table<integer, coq.Source>
+
+---@param map coq.Sources
+local function new_uid(map)
+    local key ---@type integer|nil
+    while true do
+        if not key or map[key] then
+            key = math.floor(math.random() * 10000)
+        else
+            return key
+        end
+    end
+end
+
+local function complete(args, callback)
+    if not source.enabled() then
+        callback(nil)
+        return
+    end
+
+    local last_char = args.line:sub(#args.line, #args.line)
+    if not vim.list_contains(source:trigger_characters(), last_char) then
+        callback(nil)
+        return
+    end
+
+    local row, col = unpack(args.pos) ---@type integer, integer
+
+    local items = source.items(0, row, col)
+
+    if items == nil then
+        callback(nil)
+        return
+    end
+
+    callback(items)
+end
+
+---Should only be called by a user to enable the integration
+function M.setup()
+    local has_coq = pcall(require, 'coq')
+    if not has_coq then
+        return
+    end
+    COQsources = COQsources or {} ---@type coq.Sources
+    COQsources[new_uid(COQsources)] = {
+        name = 'rMD',
+        fn = complete,
+    }
+end
+
+return M