A command can comprise of up to 4 components:
[title destination=source ~options]
Broadly speaking the title identifies the command to do, the source provides the data, options modify the command and the result is stored in the destination.
If no title is entered then the command is a ‘formats’
If no destination is entered the the result is sent straight to the ‘output’ stream.
A few single word commands have no destination, source or options e.g. [blockend]
A few multi word commands, without a destination, can cope with spaces before the ‘=’. e.g. [if not selected=v|c] executes the title ‘if not selected’, and doesn’t expect ‘selected’ to be a destination.