I haven't had much practical experience with continuations, so although I grok the general theory underlying them, I really haven't a clue what a good implementation for Perl would look like :/ Having read a bit more on this topic, it appears as if continuations are a theoretically good, but inefficient way to build the higher-level language constructs.
It is, but standards change over time. They are discussing Scheme as it pertains to future Lisp standards. Also relevent is the following quote from that paper:
In 1988, an international working group for the standardization of Lisp was formed. That group is called WG16. Two things are absolutely clear: The near-term standard Lisp is Common Lisp; a longer-term standard that goes beyond Common Lisp is desirable.
In 1988, the IEEE Scheme working group was formed to produce an IEEE and possibly an ANSI standard for Scheme. This group completed its work in 1990, and the relatively small and clean Scheme is a standard.