the "Perforce" plugin replaces the first part of the view spec by the name of the workspace.
would it be possible to provide similar functionality in the "P4" plugin.
could be as easy ae providing a ${workspace} variable, but for (backwards) compatibility it would be handy to do the same as the other plugin:

(from the "Perforce" plugin: )

Mappings: This is the depot to client mapping in the same depot-client pair format as a standard Perforce workspace spec, with a couple of handy shortcuts added: the workspace name provided in the second of each pair is not actually used--the actual workspace name is always substituted. And, the second member of any pair may be ommitted which will result in an identity mapping being used. ie, //depot/test/subdir/... will map to //workspace/test/subdir/...
If "Let Hudson/Jenkins Manage Workspace View" is checked the view entered here will overwrite the view in the existing client.

Typical examples that have the same meaning:
//depot/folder/... //workspace-name/folder/...
//depot/folder/... //anyplaceholder/folder/...
//depot/folder/...

Note:Parameter substitution of the form ${parametername} can be used anywhere in the view spec to substitute job parameters.