feat: multi selection. Only integrates with send_selected_to_qflist (#551)

This will not yet work with select actions. More work is needed in that case.

Co-authored-by: Simon Hauser <Simon-Hauser@outlook.de>

lua/telescope/pickers/highlights.lua

@@ -1,4 +1,5 @@
 local a = vim.api
+local log = require('telescope.log')
 
 local highlights = {}
 
@@ -76,25 +77,30 @@ function Highlighter:hi_selection(row, caret)
   )
 end
 
-function Highlighter:hi_multiselect(row, entry)
+function Highlighter:hi_multiselect(row, is_selected)
   local results_bufnr = assert(self.picker.results_bufnr, "Must have a results bufnr")
 
-  if self.picker.multi_select[entry] then
+  if is_selected then
     vim.api.nvim_buf_add_highlight(
-      results_bufnr,
-      ns_telescope_multiselection,
-      "TelescopeMultiSelection",
-      row,
-      0,
-      -1
+      results_bufnr, ns_telescope_multiselection, "TelescopeMultiSelection", row, 0, -1
     )
   else
-    vim.api.nvim_buf_clear_namespace(
-      results_bufnr,
-      ns_telescope_multiselection,
-      row,
-      row + 1
+    local existing_marks = vim.api.nvim_buf_get_extmarks(
+      results_bufnr, ns_telescope_multiselection, {row, 0}, {row, -1}, {}
     )
+
+    -- This is still kind of weird to me, since it seems like I'm erasing stuff
+    -- when i shouldn't... perhaps it's a bout the gravity of the extmark?
+    if #existing_marks > 0 then
+      log.trace("Clearning row: ", row)
+
+      vim.api.nvim_buf_clear_namespace(
+        results_bufnr,
+        ns_telescope_multiselection,
+        row,
+        row + 1
+      )
+    end
   end
 end
 

lua/telescope/pickers/multi.lua

@@ -0,0 +1,51 @@
+
+local MultiSelect = {}
+MultiSelect.__index = MultiSelect
+
+function MultiSelect:new()
+  return setmetatable({
+    _entries = {}
+  }, MultiSelect)
+end
+
+function MultiSelect:get()
+  local marked_entries = {}
+  for entry, count in pairs(self._entries) do
+    table.insert(marked_entries, {count, entry})
+  end
+
+  table.sort(marked_entries, function(left, right)
+    return left[1] < right[1]
+  end)
+
+  local selections = {}
+  for _, entry in ipairs(marked_entries) do
+    table.insert(selections, entry[2])
+  end
+
+  return selections
+end
+
+function MultiSelect:is_selected(entry)
+  return self._entries[entry]
+end
+
+local multi_select_count = 0
+function MultiSelect:add(entry)
+  multi_select_count = multi_select_count + 1
+  self._entries[entry] = multi_select_count
+end
+
+function MultiSelect:drop(entry)
+  self._entries[entry] = nil
+end
+
+function MultiSelect:toggle(entry)
+  if self:is_selected(entry) then
+    self:drop(entry)
+  else
+    self:add(entry)
+  end
+end
+
+return MultiSelect

lua/telescope/pickers/scroller.lua

@@ -99,4 +99,16 @@ scroller.bottom = function(sorting_strategy, max_results, num_results)
   return max_results - 1
 end
 
+scroller.better = function(sorting_strategy)
+  if sorting_strategy == 'ascending' then
+    return -1
+  else
+    return 1
+  end
+end
+
+scroller.worse = function(sorting_strategy)
+  return -(scroller.better(sorting_strategy))
+end
+
 return scroller