Of all the mythological beasts the most cruel is Haskell the vampire. Most vampires will drain you dry the moment you are bitten and death will come quickly, but that is not enough for Haskell's prey. Haskell places a curse upon you, linking your blood to her's, lazily evaluating your life force as she needs it. With this curse, Haskell will sustain herself off of you from afar while you suffer from constant blood loss, dieing after 4 - 5 months. While Haskell is immune to silver and religious symbols, she has one fatal weakness. Go to Sussman's forest and carve a staff from a tree. The staff must be exactly 2.3 meters long. Burn the tip of the staff until it's outer skin is charred black. Then place it by the fire and chant until sunrise.
``We conjure the spirits of the computer with our spells
We conjure the spirits of the computer with our spells ...''
When the sun rises, aim the staff at the icon of fire and shout ``let this staff be the weapon of the untyped lambda calculus!'' A golden lambda will descend from the sky and embed itself in the staff. Then you must etch the following inscription into the charred end of the staff.
(lambda (x) (x x))
Haskell does not come out to prey on humans often, so you must go to the cave where she lurks. This cave is no ordinary cave. Curious intruders tell stories of wandering its inside, only to find themselves back where they were when they resumed a continuation. Those less lucky tried to find there way back to the entrance, but got stuck in an infinite tunnel and died of exhaustion. Others found there way to the exit, but unfortunately the exit door only accepted entities of type LazyVampire. None have ever found the mysterious Haskell.
But with your staff, the untyped lambda calculus will light your way through the tunnel. It's golden glow will explore the routes for you, warning of these mischievous dangers. Find your way into the sacred pool of combinators. You must not be seen by Haskell. In the sacred pool, you will find the holy fix operator of the Haskell tribe. Plunge your untyped lambda staff into the operator. You will hear distant screaming, and the blue waters of the pool will turn to brownish mud. Drive the staff into the mud, and the murky pool will turn golden red. The combinators will reappear as their primitive forms expressed in the untyped lambda calculus.
The outraged Haskell will soon appear at the entrance to the sacred pool. ``WhatHastTheeDoneToMySacredCombinators!'' she shouts. ``TheseArrangementsOfSymbolsMakeNoSense!'' she barks, ``MeaninglessGarbage!'' When she attempts to decimate you and put your atoms into a list, she discovers her power is lost. At this moment, you must run up and stand within 6 feet of Haskell. Shout, ``by the power of the untyped lambda calculus, I smite thee!'' The golden expression, (lambda (x) (x x)) will fire from the staff in a beam of light, burning itself into Haskell's skin. The burning cuts will deepen and she will crumble to the floor, shouting ``TypeError!!''
This will be the end of Haskell's reign of evil. It has been forseen that a chosen one would rise as the knight of the untyped lambda calculus and smite Haskell once and for all. You are that one, reader of this inscription. Go forth and bring justice for humanity.
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Anonymous2013-07-15 14:38
>>21
Dude, you do realize that untyped lambda calculus is much more primitive and impractical than System F, right? You do know that the whole lishp type system can be represented as just 1 (one) Haskell type, right?