Sublime Plugin: Always ensures a newline at eof

ensure_newline_at_oef.py

import sublime_plugin


# Override default command here that is restricted onto real views
# (and also does not modify selection)
class EnsureNewlineAtEofCommand(sublime_plugin.TextCommand):

    def insert_nosel(self, view, edit, p, text):
        """Insert text without changing selection. Use with care.
        """
        sel = list(view.sel())
        view.sel().clear()
        view.insert(edit, p, text)
        view.sel().add_all(sel)

    def run(self, edit):
        v = self.view
        if v.settings().get("is_widget"):
            return
        if v.substr(v.size() - 1) != "\n":
            self.insert_nosel(v, edit, v.size(), "\n")

# Use Sublime's internal function to get the command name.
# `None` is only written to `self.view`, which we don't need here.
cmd_name = EnsureNewlineAtEofCommand(None).name()
setting_name = "ensure_newline_at_eof"


class ExampleEventListener(sublime_plugin.EventListener):
    # Used for locking on specific views
    undoing = []

    def on_modified(self, view):
        # Must be sync
        if view.id() not in self.undoing and view.command_history(0)[0] != cmd_name:
            view.run_command(cmd_name)

    def on_text_command(self, view, cmd, args):
        if cmd == "undo":
            # Check if disabled
            if not view.settings().get(setting_name, True):
                return

            # Prevent undoing if enaeof was the first command TODO test
            if view.command_history(-1)[0] is None:
                return ('', None)

            if view.command_history(0, True)[0] == cmd_name:
                # Don't have on_text_modified interfere here and create a lock
                self.undoing.append(view.id())
                view.run_command("undo")  # Note: this does not trigger the event hook, for some reason
                self.undoing.remove(view.id())

    def last_command_was_enaeof(self, view):
        last_command = view.command_history(0, True)[0]
        print(last_command)
        # Don't undo if enaeof was the last command
        if bool(view.command_history(1)[0]):
            return ('', None)

        return last_command == cmd_name

    # Also apply to new files
    on_load = on_modified