Merge pull request #268 from gfldex/master

doc Reduction Operators

Author: gfldex

doc/Language/operators.pod

@@ -224,7 +224,24 @@ C<%outer »+» %inner;>   only keys of %inner that exist in %outer will occur in
     say %outer «~» %inner; # {"1" => "ax", "2" => "bz"}
 
 =head2 Reduction Operators
-TODO
+
+Reduction operators apply any infix operator, surrounded by C<[> and C<]>,
+element by element and return the resulting value. They can be defined as a
+list prefix operators or will be generated automatically. 
+
+    say [+] 1,2,3; # 6
+
+For list infix operators, flattening is not done on the input list. This
+allowes list operators to become the reduction operator.
+
+    [X~] (1,2), <a b> # 1,2 X~ <a b>
+
+By default reduction meta operators are eager. To lazily generate values,
+prefix the operater with a C<\>. If the non-meta part contains a C<\> already,
+quote it with C<[]> (e.g. C<[\[\x]]>). 
+
+    my $lazy := [\+] 1..*;
+    say $lazy[^10]; # (1 3 6 10 15 21 28 36 45 55)
 
 =head2 Cross Operators
 TODO