Identifiers for transient modifications. A transient modification is uniquely identified by a Transient.t. Once Transient.freeze r is called, r cannot be used to modify the structure again.

Create a new, active ID.

Equality between IDs.

frozen i returns true if freeze i was called before. In this case, the ID cannot be used for modifications again.

active i is not (frozen i).

freeze i makes i unusable for new modifications. The values created with i will now be immutable.

with_ f creates a transient ID i, calls f i, freezes the ID i and returns the result of f i.

Raised when a frozen ID is used.