Inserting Date & Time on Mac OS

After spending twenty minutes Googling and setting up a simple Mac OS service to insert the current date and time (formatted as 2018-09-03 16.36) I thought I'd document the steps quickly.

It's very simple to set up the service using Mac's Automator:

• Launch Automator, and create a new Service.
• This particular service receives no input.
• Drag in Run AppleScript to the service.
• The script I used to insert a date is:

on run {input, parameters}
	set dateString to do shell script "date +'%Y-%m-%d %k.%M'"
	tell application "System Events"
		keystroke dateString
	end tell
	return input
end run

• Save the service and remember the name.
• Open System Preferences > Keyboard > Shortcuts and map the service to a useful keyboard shortcut.

Some interesting sticky points:

• It's remarkably painful to format a string in pure applescript, which is why I went with a custom date call. The format string is described at the date man page.
• If the shortcuts overlap in any way with the application's custom shortcuts, they won't work. I ended up choosing the relatively unergonomic ⌥ + ⌘ + , . Of course, this doesn't work in Emacs which intercepts everything.

AppleScript seems at one and the same time remarkably powerful and painful: I suspect the best way to use it is to use it carefully as a glue language, dropping out to an actual programming language (say Rust, or Python) for any actual computation.