> > The only extra piece of syntactic sugar that C<rx> is giving us over
> > C<rule>[*] is the ability to have arbitrary delimiters.
>
> Not quite arbitrary. Alphanumerics aren't allowed, nor are colon or
> parens.
Aww, no alphanumerics anymore. That's too bad; it was so nice in poetry
to be able to write:
m editate and s erpentine
> > Or, to put it more succinctly: do there exist two pieces of
> > *syntactically correct* code like
> > ... rule ...
> > and
> > ... rx ...
> > (where the ... are identical in both) which each produce *valid* and
> > *different* semantics?
>
> Yes. For example:
>
> sub foo;
>
> foo rule ($arg) { $var := <$arg> };
> foo rx ($arg) { $var := <$arg> };
>
> The first means:
>
> foo # Call foo
> rule # Passing a single pattern
> ($arg) # That takes a single parameter
> {
> $var := # And binds hypothetical $var...
> <$arg> # ...to what the parameter (treated as a pattern)
>matches
> }
> ;
>
> The second means:
>
> foo # Call foo
> rx ( # Pass, as its first argument, a pattern...
> $arg # ...that matches the contents of $arg as a literal
>string
> ) # No comma needed after first arg since next arg
>is...
Hang on... I thought parens weren't allowed as delimiters. Or does that
not apply to rx()?
> { # ...a closure...
> $var := <$arg> # ...that binds $var to a stream iterator over $arg
> }
> ;
>
>
> In other words, the second is the same as:
>
> foo rule {$arg}, sub{ $var := <$arg> };
Luke
