Support threaded reductions language extension

[Martin Sjölund]

Support threaded reductions language extension:

function testThreadedReduction
  output list<Integer> l1 := list(a+b threaded for a in 1:2, b in 3:4); // {1+3,2+4}
  output list<Integer> l2 := list(a+b for a in 1:2, b in 3:4); // {4,5,5,6}
end testThreadedReduction;

[Martin Sjölund]

Fixed in r22279.

[Henning Kiel]

Can this be implemented for for-loops as well?

threaded for a in list1, b in list2 loop
  sum := sum + a*b;
end for;

Would be syntactic sugar for

rest := list2;
for a in list1 loop
  b::rest := rest;
  sum := sum + a*b;
end for;
if not listEmpty(rest) fail();

and would avoid temporary list creation as in

tmp := list(a*b threaded for a in list1, b in list2);
for t in tmp loop
  sum := sum + t;
end for;