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nickcarenza/lazy_evaluation.go

Created February 20, 2015 18:35
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  1. nickcarenza created this gist Feb 20, 2015.
    38 changes: 38 additions & 0 deletions lazy_evaluation.go
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,38 @@
    package main

    import (
    "time"
    )

    type LazyInt chan func() int

    // Can't use pointer receiver: invalid operation: l <- (func literal) (send to non-chan type *LazyInt)
    func (l LazyInt) Future(i int) {
    l <- func() int {
    time.Sleep(3 * time.Second)
    return i
    }
    }

    func (l LazyInt) Add(i int) {
    old := <-l
    l <- func() int { return old() + i }
    }

    func addLazily(x LazyInt, y LazyInt) int {
    return (<-x)() + (<-y)()
    }

    func main() {
    var i = 1
    var a = make(LazyInt, 1)
    var b = make(LazyInt, 1)
    a <- func() int { return i }
    b <- func() int { return i }
    sum := addLazily(a, b)
    println(sum)
    var c = make(LazyInt, 1)
    c.Future(5)
    c.Add(3)
    println((<-c)())
    }