lua: add vim.highlight.range (#12401)

runtime/lua/vim/highlight.lua

@@ -2,12 +2,34 @@ local api = vim.api
 
 local highlight = {}
 
+--- Highlight range between two positions
+---
+--@param bufnr number of buffer to apply highlighting to
+--@param ns namespace to add highlight to
+--@param higroup highlight group to use for highlighting
+--@param rtype type of range (:help setreg, default charwise)
+--@param inclusive boolean indicating whether the range is end-inclusive (default false)
+function highlight.range(bufnr, ns, higroup, start, finish, rtype, inclusive)
+  rtype = rtype or 'v'
+  inclusive = inclusive or false
+
+  -- sanity check
+  if start[2] < 0 or finish[2] < start[2] then return end
+
+  local region = vim.region(bufnr, start, finish, rtype, inclusive)
+  for linenr, cols in pairs(region) do
+    api.nvim_buf_add_highlight(bufnr, ns, higroup, linenr, cols[1], cols[2])
+  end
+
+end
+
 --- Highlight the yanked region
---
+---
 --- use from init.vim via
 ---   au TextYankPost * lua require'vim.highlight'.on_yank()
 --- customize highlight group and timeout via
 ---   au TextYankPost * lua require'vim.highlight'.on_yank("IncSearch", 500)
+---
 -- @param higroup highlight group for yanked region
 -- @param timeout time in ms before highlight is cleared
 -- @param event event structure
@@ -27,10 +49,7 @@ function highlight.on_yank(higroup, timeout, event)
   pos1 = {pos1[2] - 1, pos1[3] - 1 + pos1[4]}
   pos2 = {pos2[2] - 1, pos2[3] - 1 + pos2[4]}
 
-  local region = vim.region(bufnr, pos1, pos2, event.regtype, event.inclusive)
-  for linenr, cols in pairs(region) do
-    api.nvim_buf_add_highlight(bufnr, yank_ns, higroup, linenr, cols[1], cols[2])
-  end
+  highlight.range(bufnr, yank_ns, higroup, pos1, pos2, event.regtype, event.inclusive)
 
   vim.defer_fn(
     function() api.nvim_buf_clear_namespace(bufnr, yank_ns, 0, -1) end,