What I want is:

Quick to code. One line is terrific!

Easy to define. Simply state "separate at whitespace" is very simple. That's what Forth does. I want to have "...except for quoted ones" without shifting to a more complex kind of grammar.

I'd like to write it as a built-in Perl expression, rather than loading (and learning) a parser module. Perhaps if I had Perl6 patterns I'd say that anything built-in is fine.