allow proper transparent WIN_OPEN event handling

Simply changing the file in a single WIN_OPEN event has one of two
possible problems.

1. Problem: We keep the current window
  Then all previously ran WIN_OPEN event handlers have observed a wrong
  file path, leading to broken syntax highlighting for example.
2. Problem: Use a new window
  This solves the 1. Problem by emitting a new WIN_OPEN event with
  the correct file path. However, this leads to plugins like vis-cursors
  to jump to a possibly different line rendering vis-open-extend useless.

The solution to both problems is to split our event handling in two
parts:

On the original event detect the file and the specified line.
Change to the file in a new window, remember the line and stop
the event handling for the first event.

On the second WIN_OPEN event for the correct file path simply
jump to the remembered line.

This allows both plugins vis-open-extend and vis-cursors to work,
if vis-open-extend is loaded after vis-cursors, so our event handler
runs after the one from vis-cursors.

1 files changed, 19 insertions, 3 deletions

diff --git a/init.lua b/init.lua
index 2bb477c..3d46b89 100644
--- a/init.lua
+++ b/init.lua
@@ -7,22 +7,38 @@ local function file_exists(path)
 	return out
 end
 
+--- Store the paths we opened to change their line in the second WIN_OPEN event
+local paths = {}
+
 vis.events.subscribe(vis.events.WIN_OPEN, function(win)
 	if win.file == nil or win.file.path == nil then return end
 	local ref = win.file.path
 
+	-- If this is a file we opened, simply go to the saved line.
+	if paths[ref] then
+		vis:feedkeys(tostring(paths[ref]).."G")
+		paths[ref] = nil
+		return
+	end
+
 	-- if the file with colon actually exists, don't do anything
 	if file_exists(ref) then
 		return
 	end
 
 	local _, _, path, line = string.find(ref, "^(.+):(%d+)$")
-	if path == nil or line == nil or line == 0 or not file_exists(path) then
+	if path == nil or line == nil or line == 1 or not file_exists(path) then
 		return
 	end
+
+	-- Store the file's path to go to line in the next WIN_OPEN event
+	paths[path] = line
 	win:close()
 	win.file = path
+	-- Open the actual file path. This creates a new window and emits a new
+	-- WIN_OPEN event, which we use to set the correct line.
 	vis:command("e "..path)
-	vis:command("+"..line-1)
--- or vis:feedkeys(tostring(line).."G") 
+ -- Prevent other WIN_OPEN event handlers from running after we closed the window.
+	return true
 end)
+