0 used to refer to computer files or memory that can be read or used, but not changed or added to in any way:
There's a read-only view that lets users view, but not change, a document.
You're currently viewing as a guest, which gives you limited read-only access.
It is then possible to export variables (mutable bindings) or functions (read-only bindings).
The generalisations we consider are those from deterministic to non-deterministic machines, from one-way to two-way machines, and from read-only machines to read/write machines.
Finally, variables can be freely used with aspect 3, the pure "read-only" usage.
This is a way of expressing the fact that the pivot is a read-only element and, as such, can be accessed concurrently.
The security support also includes read-only views of logic variables.
