Presented at Perl Seminar NY (PerlSemNY), February 2011.

1. Operator::Util
Nick Patch
Perl Seminar NY
15 February 2011

2. released yesterday

3. released yesterday
i ♥ feedback

4. Perl 6 is pretty cool

5. meta-operators

6. meta-operators
[ ☺] Z ☺ X ☺ » ☺«

7. reduction
[+] 1..4 # 10
[*] 1..4 # 24
[~] 'a'..'d' # 'abcd'

8. zip
(1,2) Z+ (2,3) # 3,5
(1,2) Z* (2,3) # 2,6
(1,2) Z~ <a b> # 1a,2b

9. cross (flat)
(1,2) X+ (2,3) # 3,4,4,5
(1,2) X* (2,3) # 2,3,4,6
(1,2) X~ <a b> # 1a,1b,2a,2b

10. cross (lol)
(1,2) X+ (2,3) # [3,4],[4,5]
(1,2) X* (2,3) # [2,3],[4,6]
(1,2) X~ <a b> # [1a,1b],[2a,2b]

11. hyper
1..4 »~« 'a'..'d' # 1a,2b,3c,4d
1..4 »~» 'x' # 1x,2x,3x,4x
1..4 «~» <x y> # 1x,2y,1x,2y
1..4 «~« <x y> # 1x,2y

12. more hyper!
-« (1,2,3) # -1,-2,-3
[1,[2,3]] »++ # [2,[3,4]]
%foo «+» %bar # intersection
%foo »+« %bar # union
%foo »+=« %bar # %foo = union

13. but it's not Xmas yet

14. cpanm Operator::Util

15. use Operator::Util qw(
reducewith
zipwith
crosswith
hyperwith
);

16. reducewith a.k.a. reduce
hyperwith a.k.a. hyper

17. reduction
reduce('+', [1..4]) # 10
reduce('*', [1..4]) # 24
reduce('.', ['a'..'d']) # 'abcd'

18. zip
zipwith('+', [1,2], [2,3]) # 3,5
zipwith('*', [1,2], [2,3]) # 2,6
zipwith('.', [1,2], ['a','b']) # 1a,2b

19. cross (flat)
crosswith('+', [1,2], [2,3])
crosswith('*', [1,2], [2,3])
crosswith('.', [1,2], ['a','b'])
# 3,4,4,5
# 2,3,4,6
# 1a,1b,2a,2b

20. cross (lol)
crosswith('+', [1,2], [2,3], flat=>0)
crosswith('*', [1,2], [2,3], flat=>0)
crosswith('.', [1,2], ['a','b'], flat=>0)
# [3,4],[4,5]
# [2,3],[4,6]
# [1a,1b],[2a,2b]

21. hyper
hyper('.', [1..4], ['a'..'d'] );
hyper('.', [1..4], 'x', dwim_right=>1);
hyper('.', [1..4], ['x','y'], dwim=>1 );
hyper('.', [1..4], ['x','y'], dwim_left=>1 );
# 1a,2b,3c,4d
# 1x,2x,3x,4x
# 1x,2y,1x,2y
# 1x,2y

22. more hyper!
hyper('prefix:-', [1,2,3]);
hyper('postfix:++', [1,[2,3]]);
hyper('+', %foo, %bar, dwim=>1);
hyper('+', %foo, %bar);
hyper('+=', %foo, %bar);
# -1,-2,-3
# [2,[3,4]]
# intersection
# union
# %foo = union

23. default ops
zipwith(',', [1,2], ['a','b'])
zip( [1,2], ['a','b'])
crosswith(',', [1,2], ['a','b'])
cross( [1,2], ['a','b'])
# 1,a,2,b
# 1,a,2,b
# 1,a,1,b,2,a,2,b
# 1,a,1,b,2,a,2,b

24. associativity
reduce('-', [4, 3, 2])
reduce('**', [4, 3, 2])
# 4-3-2 = (4-3)-2 = -1
# 4**3**2 = 4**(3**2) = 262144

25. chaining
reduce('eq', @a) # all elements eq?
reduce('!=', @c) # no repeating elements?
reduce('<', @b) # ascending elements?

26. dwim for < 2 elems
reduce('+', [] ) # 0
reduce('+', [5]) # 5
reduce('*', [] ) # 1
reduce('*', [5]) # 5

27. even more hyper!
hyper('->', @objects, 'run', dwim=>1)
hyper('+', [[1, 2], 3], [4, [5, 6]], dwim=>1)
hyper('prefix:-', {a => 1, b => 2, c => 3})
# call ->run() on each
# [[5, 6], [8, 9]]
# a => -1, b => -2, c => -3

28. resources
git: github.com/patch
slides: patch.github.com