Variable Assignment

[trulede]

The Rivet Variable Assignment Matrix

Operator	Timing	Condition	Value Type	Example Usage
(none)	Immediate	Always	Plain Text / Shell	foo: bar or sha: $git rev-parse HEAD
?	Immediate	If Empty	Plain Text / Shell	port: ?8080 or user: ?$whoami
~	Lazy	Always	Plain Text / Shell	time: ~$date
~?	Lazy	If Empty	Plain Text / Shell	cache: ~?$/tmp/data
~+	Lazy	Append	Plain Text / Shell	path: ~+$echo "/bin"

Still to decide:

• executable as $ ?
• variable expansion/reference, . or $() or something else (not go template)

Existing templating remains.