1 files changed, 86 insertions, 0 deletions
diff --git a/src/gen/gen_keycodes.lua b/src/gen/gen_keycodes.lua
new file mode 100644
index 0000000000..53f0c24e58
--- /dev/null
+++ b/src/gen/gen_keycodes.lua
@@ -0,0 +1,86 @@
+local names_file = arg[1]
+
+local hashy = require('gen.hashy')
+local keycodes = require('nvim.keycodes')
+
+local keycode_names = keycodes.names
+
+--- @type table<string,integer>
+--- Maps lower-case key names to their original indexes.
+local name_orig_idx = {}
+
+--- @type table<string,integer>
+--- Maps keys to the original indexes of their preferred names.
+local key_orig_idx = {}
+
+--- @type [string, string][]
+--- When multiple keys have the same name (e.g. TAB and K_TAB), only the first one
+--- is added to the two tables above, and the other keys are added here.
+local extra_keys = {}
+
+for i, keycode in ipairs(keycode_names) do
+  local key = keycode[1]
+  local name = keycode[2]
+  local name_lower = name:lower()
+  if name_orig_idx[name_lower] == nil then
+    name_orig_idx[name_lower] = i
+    if key_orig_idx[key] == nil then
+      key_orig_idx[key] = i
+    end
+  else
+    table.insert(extra_keys, keycode)
+  end
+end
+
+local hashorder = vim.tbl_keys(name_orig_idx)
+table.sort(hashorder)
+local hashfun
+hashorder, hashfun = hashy.hashy_hash('get_special_key_code', hashorder, function(idx)
+  return 'key_names_table[' .. idx .. '].name.data'
+end, true)
+
+--- @type table<string,integer>
+--- Maps keys to the (after hash) indexes of the entries with preferred names.
+local key_hash_idx = {}
+
+for i, lower_name in ipairs(hashorder) do
+  local orig_idx = name_orig_idx[lower_name]
+  local key = keycode_names[orig_idx][1]
+  if key_orig_idx[key] == orig_idx then
+    key_hash_idx[key] = i
+  end
+end
+
+local names_tgt = assert(io.open(names_file, 'w'))
+names_tgt:write([[
+static const struct key_name_entry {
+  int key;                  ///< Special key code or ascii value
+  String name;              ///< Name of key
+  const String *pref_name;  ///< Pointer to preferred key name
+                            ///< (may be NULL or point to the name in another entry)
+} key_names_table[] = {]])
+
+for i, lower_name in ipairs(hashorder) do
+  local keycode = keycode_names[name_orig_idx[lower_name]]
+  local key = keycode[1]
+  local name = keycode[2]
+  local pref_idx = key_hash_idx[key]
+  names_tgt:write(
+    ('\n  {%s, {"%s", %u}, %s},'):format(
+      key,
+      name,
+      #name,
+      pref_idx == i and 'NULL' or ('&key_names_table[%u].name'):format(pref_idx - 1)
+    )
+  )
+end
+
+for _, keycode in ipairs(extra_keys) do
+  local key = keycode[1]
+  local name = keycode[2]
+  names_tgt:write(('\n  {%s, {"%s", %u}, NULL},'):format(key, name, #name))
+end
+
+names_tgt:write('\n};\n\n')
+names_tgt:write('static ' .. hashfun)
+names_tgt:close()