From a5526fb2ee963cf426ab6d6ba1f3eb82887b1c22 Mon Sep 17 00:00:00 2001
From: Steven Arcangeli <506791+stevearc@users.noreply.github.com>
Date: Fri, 29 Sep 2023 11:56:21 -0700
Subject: feat: format injected languages (#83)

---
 lua/conform/formatters/injected.lua | 98 +++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 lua/conform/formatters/injected.lua

(limited to 'lua/conform/formatters')

diff --git a/lua/conform/formatters/injected.lua b/lua/conform/formatters/injected.lua
new file mode 100644
index 0000000..c25f2f9
--- /dev/null
+++ b/lua/conform/formatters/injected.lua
@@ -0,0 +1,98 @@
+---@param range? conform.Range
+---@param start_lnum integer
+---@param end_lnum integer
+---@return boolean
+local function in_range(range, start_lnum, end_lnum)
+  return not range or (start_lnum <= range["end"][1] and range["start"][1] <= end_lnum)
+end
+
+---@type conform.FileLuaFormatterConfig
+return {
+  meta = {
+    url = "lua/conform/formatters/injected.lua",
+    description = "Format treesitter injected languages.",
+  },
+  condition = function(ctx)
+    local ok = pcall(vim.treesitter.get_parser, ctx.buf)
+    return ok
+  end,
+  format = function(ctx, lines, callback)
+    local conform = require("conform")
+    local util = require("conform.util")
+    local ok, parser = pcall(vim.treesitter.get_parser, ctx.buf)
+    if not ok then
+      callback("No treesitter parser for buffer")
+      return
+    end
+    local root_lang = parser:lang()
+    local regions = {}
+    for lang, child_lang in pairs(parser:children()) do
+      local formatter_names = conform.formatters_by_ft[lang]
+      if formatter_names and lang ~= root_lang then
+        for _, tree in ipairs(child_lang:trees()) do
+          local root = tree:root()
+          local start_lnum = root:start() + 1
+          local end_lnum = root:end_()
+          if start_lnum <= end_lnum and in_range(ctx.range, start_lnum, end_lnum) then
+            table.insert(regions, { lang, start_lnum, end_lnum })
+          end
+        end
+      end
+    end
+    -- Sort from largest start_lnum to smallest
+    table.sort(regions, function(a, b)
+      return a[2] > b[2]
+    end)
+
+    local replacements = {}
+    local format_error = nil
+
+    local function apply_format_results()
+      if format_error then
+        callback(format_error)
+        return
+      end
+
+      local formatted_lines = vim.deepcopy(lines)
+      for _, replacement in ipairs(replacements) do
+        local start_lnum, end_lnum, new_lines = unpack(replacement)
+        for _ = start_lnum, end_lnum do
+          table.remove(formatted_lines, start_lnum)
+        end
+        for i = #new_lines, 1, -1 do
+          table.insert(formatted_lines, start_lnum, new_lines[i])
+        end
+      end
+      callback(nil, formatted_lines)
+    end
+
+    local num_format = 0
+    local formatter_cb = function(err, idx, start_lnum, end_lnum, new_lines)
+      if err then
+        format_error = err
+      else
+        replacements[idx] = { start_lnum, end_lnum, new_lines }
+      end
+      num_format = num_format - 1
+      if num_format == 0 then
+        apply_format_results()
+      end
+    end
+    local last_start_lnum = #lines + 1
+    for _, region in ipairs(regions) do
+      local lang, start_lnum, end_lnum = unpack(region)
+      -- Ignore regions that overlap (contain) other regions
+      if end_lnum < last_start_lnum then
+        num_format = num_format + 1
+        last_start_lnum = start_lnum
+        local input_lines = util.tbl_slice(lines, start_lnum, end_lnum)
+        local formatter_names = conform.formatters_by_ft[lang]
+        local format_opts = { async = true, bufnr = ctx.buf, quiet = true }
+        local idx = num_format
+        conform.format_lines(formatter_names, input_lines, format_opts, function(err, new_lines)
+          formatter_cb(err, idx, start_lnum, end_lnum, new_lines)
+        end)
+      end
+    end
+  end,
+}
-- 
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