This Statement Is False

Dot #1: Lambda Calculus... My wife and I took a vacation recently and I had a chance to learn some more Lambda Calculus; how the Y-combinator works, in particular. At Purdue, we focused on Turing Machines and either we didn't really cover LC or I slept during that part. If you haven't, I HIGHLY recommend learning LC. Lambda Calculus is the most elegant system I, personally, know of (maybe that's not saying much). You functional-types out there will already know this next part, but here's some history and stuff. It was invented by Alonzo Church, who was Turing's Ph. D. adviser (later they proved that the Lambda Calculus and Universal Turning Machines are equivalent, which was one really impressive feat). The Y-combinator is a way to define recursive functions using only lambda binding. Lambda binding is very simple and it's pretty much what Lambda Calculus is. It more or less just lets you assign values to variables and then use them in an expression, lik...

OK, revisiting this topic after a very short time, I have a new implementation, again using that interesting anonymous class technique from James Iry's comment: implicit def richOption[T](x : T) = new { def ??[B](f : T => B):B = if (x != null) f(x) else null.asInstanceOf[B] } I changed the operator from "?!" to "??" because that's a lot easier to type and I chose "??" instead of "?" so people wouldn't confuse it with the questi-colon operator from Java and C. It's stand-alone (doesn't depend on Option or anything) and I had to use a cast to get the types to work out properly, but the test case from my last post does work println(p3??(_.bud)??(_.bud)??(_.bud)??(_.name.drop(1))) prints null and println(p3??(_.bud)??(_.bud)??(_.name.drop(1))) prints ubba. For those new to Scala, the expressions in parentheses are anonymous functions because they use "_" as identifiers. (_.bud) expands to (x => x.bud), where Sca...

Welcome to my first blog post. I searched the net for a Scala analog to Groovy's safe navigation, but I didn't find anything, so I made my own. It's like a monad but I haven't thought much about the implications of really making it into a real monad so I haven't monadized it at this point. Here is some example data to demonstrate how you use these safe navigation operators in Scala: case class Person(var name: String, var bud: Person = null) val p1 = new Person("bubba") val p2 = new Person("fred", p1) val p3 = new Person("mary", p2) println(opt(p3)?!(_.bud)?!(_.bud)!(_.name.drop(1))) This code prints "ubba". It uses ?! like Groovy's ?. operator (?. isn't a legal operator in Scala because of the .), but you need the extra parentheses or it doesn't parse like you would want (I think Scala needs the parentheses to disambiguate the scope for the _). The final ! operator returns the closure value instead of wrapping ...