• prefixBinding ?-infix regex? ?-prompt str?
Build composite bindings. For instance, to create a binding ctrl-a opt-b, one must create a binding for ctrl-a and associate it with this command, then define a binding for opt-b with ctrl-a prefix. See the documentation of the [binding] command.
The -infix option is used to build composite bindings with an infix so that the user can execute for instance ctrl-a 5 opt-b (here the infix is 5 and means that the action linked to the combo will receive the value 5 as an additional argument which it can interpret in different ways). The value of the -infix option is a regular expression which describes which values are considered an infix: for instance [1-5r] means that the infix could be a digit between 1 and 5 or the letter r.
The -prompt option is used to provide a string to display in the status bar of the application. If it is not specified, the command displays a default string.
See the Bindings with an infix section in the reference for the [binding] command.