例によって時間が押してできなかったLightning Talksのネタを上げておきます. ま, 誰でも知っているようなつまらないネタですけど...

1. MONAD ON GROOVY
==
MANADOLOGIE
masaki@metabolics.co.jp
2011.06.17
1

2. monad?
Haskell
monoid
continuation
......
2

3. monad!
( )
Haskell
Maybe Monad Groovy (2009/8/30, Gr )
3

4. example 1
2
S = {2x|x ∈ N, x > 3}
(comprehension)
x 3 ,2 *x
4

5. groovy way
def s(n) {
((0..n)
.findAll { it**2 > 3 })
.collect { it*2 }
}
Groovy ,
5

6. example 2
import static hr.helix.monadologie.MonadComprehension.foreach
def s(n) {
foreach {
x = takeFrom { 0..n }
guard { x**2 > 3 }
yield { 2*x }
}
}
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7. example 3
def pythags(n) {
foreach {
z = takeFrom { 1..n }
x = takeFrom { 1..z }
y = takeFrom { x..z }
guard { x**2 + y**2 == z**2 }
yield { [x, y, z] }
}
}
assert pythags(12) == [[3, 4, 5], [6, 8, 10]]
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8. monadologie
https://github.com/dsrkoc/monadologie
by Dinko Srkoc
8

9. what’s the point
monadologie ?
=> Collection ,
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10. interface Monad<M> {
M unit(Object a)
M bind(Closure f)
}
10

11. List (!)
(List<X> X )
List<X> (X a) = { [a] } //
List<Y> (List<X> m, f) =
{ m.inject([]) { r, e -> r + f(e) } } //
// where f s.t. List<Y> f(X x)
// f apply []
11

12. unit, bind
bind(m, unit) == m
bind(unit(m), f) == f(m) //
bind(bind(m, f), g) ==
bind(m, { bind(f(it), g) }) //
12

13. Groovy ?
=> List (Collection)
,
( )
...
13

14. Option - (e.g. null)
Maybe Groovy safe reference “?.”
Either -
Reader - Closure
Writer -
State -
STM -
memoize, ,
AST
14

15. , ?
( )
...:-)
15

16. LT
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