what happened to that new isset() like language construct

On 4/15/2004 Jason Garber asked about a new language construct to simplify testing if a variable isset() and assinging a default value for those that aren't. The thread title was "Construct Request". I rember reading it while the discussion went on, I just went back and browsed through it again. Everyone seemed to agree the it was generally a good idea and there was some minimal amount of consensus on the ?: syntax, but I can't tell if this was ever implemented. Was it? If not did I miss the reason why? Marc