I'm trying to write a revised operator precedence table for perl6,
similar to the one in perlop.pod.
This is what I have come up with based on Apocalypse 3 and Exegesis 3.
Does anyone have comments? I'm not sure if the precedence
for : (adverb) or 'is' and 'but' are quite right.
perl6 operator precedence
left terms and list operators (leftward) [] {} () quotes
left . and unary .
nonassoc ++ --
left is but
right **
right ! \ and unary ~ + - * _
left =~ !~
left * / % x
left + - _
left << >>
right named unary operators, -X
left < > <= >= lt gt le ge == != <=> eq ne cmp
left &
left | ~
left &&
left || ~~ //
nonassoc .. ...
right ??::
right = := **= += -= _= *= /= %= x= &= |= ~=
<<= >>= &&= ||= ~~= //=
left , =>
left ;
left :
nonassoc list operators (rightward)
right not
left and
left or xor err
Here is a list of changes from perl5:
. becomes _
-> becomes .
== etc unified with < etc, and given left associativity
binary ^ becomes ~
?: becomes ??::
added ~~ // err
added ; with lower precedence than ,
added unary * and _ with same precedence as unary + -
added binary :=
added unary . with same precedence as binary .
( .foo === $self.foo )
added : (adverb operator) with low precedence(?)
print foo: $x, $y, $z; # lower than ,
my $fh = open $filepath : mode=>'rw'; # lower than =>
added 'is' and 'but' with high precedence(?)
my $thing is constant = 3 but false; # higher than =
Larry mentions that other precedence unifications are possible. I can see
the following as possibilites. Are there others?
& with &&
| with ||
<< >> with * /
~ John Williams
