This is just a laundry list of items completed and items on the
"to do" list for PGE.  One of the best incentives for getting a
feature off a "to do" list and onto a "done" list is to submit
a test for the feature.  :-)

Perl 6 rule features implemented
--------------------------------
* standard regular expression constructs
* quantifiers (*, +, ?, *?, +?, ??, **{m..n}?)
* cut operators (:, ::, :::, <commit>)
* alternation  (|)
* conjunction  (&)
* capturing and non-capturing groups
* modifiers :i, :ignorecase, :s, :sigspace (with synonyms :w and :words)
* enumerated character lists (<[abcdef]>, <-[a..f]>)
* composed character classes (<+alpha-[aeiou]>)
* character classes (., \d, \w, \s, \n, \e, \f, \r, \t, \x[hhh], \o[nnn])
* anchors (^, $, ^^, $$, \b, \b)
* negated character classes 
* \c[...] and \C[...]
* capturing subrules (<expr>)
* non-capturing subrules  (<.expr>)
* negated subrules (<!expr>)
* lookahead and lookbehind (<before> and <after>)
* built-in rules: <null>, <fail>, <alpha>, <digit>, <alnum>, 
    <upper>, <lower>, <xdigit>, <space>, <print>, <graph>,
    <blank>, <cntrl>, <punct>, <sp>, <lt>, <gt>, <dot>, <ws>,
    <p6rule>, <p5regexp>
* backreferences ($0, $1, $<foo>)
* scalar subrule and subpattern aliases ($<foo>:=(...), $0:=(...))
* balanced delimited text (<PGE::Text::bracketed>)
* embedded closures ({{ puts "hello" }})
* :lang() modifier
* firstchar/nextchar optimizations


Perl 6 rule features to-do
--------------------------
* lookbehind according to S05 definition 
* <cut> assertion
* versions of <commit> and cuts that release backtracking state
* :perl5 modifier
* literal assertions (<'literal'>)
* interpolated assertions (<"literal">)
* array and hash aliasing (@<foo>:=(...), %<foo>:=(...))
* don't generate unneeded internal data structures (e.g., gpad)


Perl 5 regexp features implemented
----------------------------------
* basic regular expressions
* quantifiers (*, +, ?, *?, +?, ??, {m,n}?)
* alternation (|)
* character classes ([a-z], [^aeiou])
* character class shortcuts (\d, \n, \s, \w, .)
* anchors (^, \b, \B)
* capturing parens
* non-capturing parens (?:...)


Perl 5 regexp features to-do
----------------------------
* modifiers   (?imxs:...)
* lookahead, lookbehind
* backreferences (\1, \2, \3)
* character class shortcuts in [...]   ([^\S\n])
* global anchors (\A, \a, \z)
* correct implementation of $ anchor
* hexadecimal, octal, and other chars (\x{hhhh}, \012, \cX)

