Prefixed Labels

Labels of the form a.x, a.y, a.z can be referred to using the prefix a in relabelling and hiding expressions. A label declared as a[1], is compiled to a.1.

BUF = (in[x:0..2]->out[x]->BUF).
||TWOBUF = (BUF/{mid/out} || BUF/{mid/in})\{mid}.

In the example above, out refers to the action labels out.0, out.1, out.2. After the relabelling function /{mid/out} is applied to BUF, these become mid.0, mid.1, mid.2. All of these labels are concealed by \{mid}.

This mechanism is useful for managing the alphabet of a composite process as a set of interfaces, each with a different prefix.