Sgeo

#lang racket/base
 
(require racket/control)
 
(struct monad (bind return) #:transparent)
 
(define-syntax-rule (with-monad ([val m]) body ...)
  (let* ([m-once m]
        [val
         (lambda (ma)

Sgeo

#lang racket/base

(require racket/function
         racket/list
         racket/dict)

(provide (struct-out lens)
         lens-get
         lens-mod
         lens-set

Sgeo

use [num] [
    num: 0
    count: func [x] [
        num: num + x
        print num
    ]
]
count 1 count 1 count 1

Sgeo

REBOL [
  Title: "Monads"
  Author: "Sgeo"
]

do-monad: func [
  monad "An object containing a /bind and a /return."
  assigns [block!]
  result [block!]
  /local ma f next-assigns arg

Sgeo

/* code taken verbatim from http://www.scala-lang.org/api/current/index.html#scala.util.control.TailCalls$ */

def isEven(xs: List[Int]): TailRec[Boolean] =
    if (xs.isEmpty) done(true) else tailcall(isOdd(xs.tail))
 
def isOdd(xs: List[Int]): TailRec[Boolean] =
    if (xs.isEmpty) done(false) else tailcall(isEven(xs.tail))

Sgeo

listEven :: [a] -> Bool
listEven [] = True
listEven (_:xs) = listOdd xs

listOdd :: [a] -> Bool
listOdd [] = False
listOdd (_:xs) = listEven xs

Sgeo

waitFor: anAnnouncementClass
  "Blocks the current process until anAnnouncementClass is announced.
	Note that synchronous code using this method runs the risk of missing announcements."
	| val sem |
	sem := Semaphore new.
	self on: anAnnouncementClass do: [:ann | val := ann. sem signal].
	sem wait.
	^val.
	

Sgeo

DynamicVariable subclass: #DynamicGeneratorVar
  instanceVariableNames: ''
	classVariableNames: ''
	poolDictionaries: ''
	category: 'Sgeo-DynamicGenerator'!
!DynamicGeneratorVar commentStamp: 'SethJGold 1/14/2013 06:41' prior: 0!
DynamicGeneratorVar holds the current DynamicGenerator in use. Should not be used directly by client code.!




Sgeo

#_(deftest maybe-plus
  (is (= :bogus
         @(m/plus [m/maybe-zero-val
                   (m/do m/maybe
                         [_ (m/maybe 1)]
                         (throw (Exception. "Should not be thrown")))]))))

Sgeo

(ns delimonads.core
  (:require [monads.core :as m])
  (:use delimc.core))


(reset
 (defn bind-cont
   "Binds its monadic value argument to the continuation.
Easy to understand explanation: (f (bind-cont x) y) becomes do {x' <- x; f x' y}"
   [monadic-value]