[p4] p4 uri

[Roger Day]

I currently maintain 2 SCM systems - an internal one and P4. To allow my 
scripts to process references to files in both SCM systems with standard 
URL classes (in python) I'm thinking of using a URL-like string to 
identify files in either system .i.e

hope://<hostname>/<filepath> 

p4://<hostname>/<filepath>

with depot dropping out as the default. Which kinda seems wrong to me. It 
seems to me that the full path should be invoked. But  a full WWW-like URI 
would look like:

///depot/

with hostname and protocol left out for defaults. Any background on why 
the two notations differ?

What do others do? Is there a recognised or defacto way of addressing p4 
resources similarly? 

TIA
Roger