Read-only Bindings interface

[Tpt]

The Bindings interface is currently read-write. It might be convenient to provide also a smaller read-only interface for implementations which do not allow to change bindings like Oxigraph.

[l00mi]

What is the advantage of having a specific read-only interface? What is the downside if the write operations throw an error if not implemented?

[tpluscode]

What is the advantage of having a specific read-only interface?

Principle of least surprise

If an interface is read-only, you will get design-time error. An exception is a runtime surprise waiting to happen.

I think I proposed something like that in the lengthy PR #7 discussions but could not quickly find that specific comment. IIRC, the argument was that a result stream is not only intended for end consumers but even more so to query processors and intermediaries which may modify the bindings.

/cc @rubensworks

[rubensworks]

I'm definitely open to this. I guess this can easily be added in a non-breaking manner.
Feel free to suggest something via a PR.