vis-lua: introduce pre-save hook

The first argument is the file object while the second argument denotes
the full path to which it will be written. Path might be `nil` if the
file is going to be written to stdout.

The Lua function is expected to return a boolean value indicating whether
the write operation should proceed or be aborted.

1 files changed, 1 insertions, 0 deletions

diff --git a/vis.h b/vis.h
index f3366c7..9d6ba4d 100644
--- a/vis.h
+++ b/vis.h
@@ -32,6 +32,7 @@ typedef struct {
 	void (*vis_start)(Vis*);
 	void (*vis_quit)(Vis*);
 	void (*file_open)(Vis*, File*);
+	bool (*file_save_pre)(Vis*, File*, const char *path);
 	void (*file_save_post)(Vis*, File*, const char *path);
 	void (*file_close)(Vis*, File*);
 	void (*win_open)(Vis*, Win*);