vis-lua: add file:snapshot method

A number of plugins, for example vis-spellcheck[0], want to
perform bulk edits on the file text. They may desire for those
edits to be split into multiple undo/redo points. This is
achievable by switching the mode between insert and normal mode
but that has other side effects. Instead introduce a method of
doing this directly.

[0]: https://gitlab.com/muhq/vis-spellcheck

1 files changed, 12 insertions, 0 deletions

diff --git a/vis-lua.c b/vis-lua.c
index 7986503..e226d18 100644
--- a/vis-lua.c
+++ b/vis-lua.c
@@ -2675,6 +2675,17 @@ static int file_delete(lua_State *L) {
 }
 
 /***
+ * Create a restore point for undo/redo.
+ *
+ * @function snapshot
+ */
+static int file_snapshot(lua_State *L) {
+	File *file = obj_ref_check(L, 1, VIS_LUA_TYPE_FILE);
+	text_snapshot(file->text);
+	return 0;
+}
+
+/***
  * Create an iterator over all lines of the file.
  *
  * For large files this is probably faster than @{lines}.
@@ -2817,6 +2828,7 @@ static const struct luaL_Reg file_funcs[] = {
 	{ "__newindex", file_newindex },
 	{ "insert", file_insert },
 	{ "delete", file_delete },
+	{ "snapshot", file_snapshot },
 	{ "lines_iterator", file_lines_iterator },
 	{ "content", file_content },
 	{ "mark_set", file_mark_set },