OCL25 — Issue: Signature of Environment

Description: The specification (in the standard) of the Environment class is missing a few things that are used or referred to elsewhere in the standard; some are missing altogether and some are missing from the class diagram:
The association from an environment to its parent.
The operations lookupImplicitSourceForOperation, lookupPathName, addEnvironment
Rationale: We show a more complete specification below. We also add a convenience method addVariableDeclaration; although not necessary as addElement can be used to add a VariableDeclaration, this operation avoids the need to construct the VariableDeclaration before adding it to the environment.
The specification of the Environment operations uses various methods on the bridge classes; we have added these operations to the classes, as shown in the previous section about the bridge classes.