Browse by Tags

• C#
• Code Quality
• Continuation Passing Style
• JScript
• Performance
• Rarefied Heights
• VBScript

• Recursion, Part Six: Making CPS Work

  JScript doesn't support CPS natively but we can write another dispatch engine that makes it work. There's only ever one active continuation, so lets have a new rule: JScript CPS functions are allowed to return, but the last thing that they do must be Read More... Posted Monday, August 15, 2005 3:00 AM by Eric Lippert | 2 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion, Continuation Passing Style

• Recursion, Part Five: More on CPS

  Suppose we wanted to write this by-now-familiar little function in continuation passing style: function treeDepth(curtree) { if (curtree == null) return 0; else { var leftDepth = treeDepth(curtree.left); var rightDepth = treeDepth(curtree.right); return Read More... Posted Thursday, August 11, 2005 3:00 AM by Eric Lippert | 0 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion, Continuation Passing Style

• Recursion, Part Four: Continuation Passing Style

  We're getting hung up on the stack management aspects of recursive programming. Why do we need a stack at all? What purpose does it serve? If you're like most developers, you probably learned about subroutines and functions at an early age. The idea is Read More... Posted Monday, August 08, 2005 3:00 AM by Eric Lippert | 3 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion, Continuation Passing Style

• Recursion, Part Three: Building a Dispatch Engine

  There's a particular technique that I like to use to solve problems -- it doesn't always work, but when it does, it can produce programs of surprising elegance and power. The technique is this: if you have a specific problem to solve, solve a more general Read More... Posted Thursday, August 04, 2005 3:00 AM by Eric Lippert | 0 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion

• Recursion, Part Two: Unrolling a Recursive Function With an Explicit Stack

  That recursive solution is pretty cool, to be sure. But there is one big problem with it. Consider this Jscript program that puts a few more nodes into our tree from last time: function tree(value, left, right) { this.value = value; this.left = left; Read More... Posted Monday, August 01, 2005 3:00 AM by Eric Lippert | 3 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion

• Recursion, Part One: Recursive Data Structures and Functions

  The first thing to wrap your head around is recursively defined data structures. Let's start with something simple. Think about the abstract idea of “list”. Most people think of a “list” as an ordered collection of “items”, one after the other, with a Read More... Posted Wednesday, July 27, 2005 3:00 AM by Eric Lippert | 7 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion

• Recursion, Part Zero

  I’ve mentioned recursive programming techniques several times over the years in this blog ( Topological Sort , How Not To Teach Recursion , Fibonacci Challenge , Recursion and Dynamic Programming , Sometimes Breadth Is Better Than Depth , and probably Read More... Posted Monday, July 25, 2005 3:00 AM by Eric Lippert | 6 Comments Filed under: JScript, Scripting, Rarefied Heights, Recursion

• Bad Recursion Revisited

  We have internal email lists for questions about programming languages. Here's one that came across recently that I thought illustrated a good point about language design. An interview candidate gave the following awful implementation of the factorial Read More... Posted Thursday, April 28, 2005 12:12 PM by Eric Lippert | 20 Comments Filed under: JScript, VBScript, Scripting, C#, Code Quality, Recursion

• Breadth is sometimes better than depth

  A while back the Scripting Guys blogged about using recursion to list all the files in a directory and all its subdirectories. Something that you'll notice about this very standard solution to this problem is that it is "depth first". That is, it lists Read More... Posted Monday, September 27, 2004 10:58 AM by Eric Lippert | 16 Comments Filed under: JScript, Scripting, Recursion

• Recursion and Dynamic Programming

  Back in May we were discussing the merits and drawbacks of recursive programming techniques -- that is, writing functions which break down problems into sub-problems, and then call themselves. The drawback of such an approach is that in some cases, you Read More... Posted Wednesday, July 21, 2004 9:43 AM by Eric Lippert | 10 Comments Filed under: JScript, Scripting, Performance, Rarefied Heights, Recursion

• Results Of The Fibonacci Challenge Are In

  Another bunch of good replies to my challenge of yesterday. And again, a bunch of answers that I didn't expect, and some of the points that I was thinking of weren't mentioned. People seem to like this more conversational format; I'll probably use it Read More... Posted Thursday, May 20, 2004 5:11 PM by Eric Lippert | 5 Comments Filed under: Scripting, Performance, Recursion

• How Not To Teach Recursion

  A Joel On Software reader asked the other day for examples of recursive functions other than old chestnuts like Fibonacci or factorial. Excellent question. I suggested topological sort , of course, but there are plenty of other examples that are way better Read More... Posted Wednesday, May 19, 2004 3:12 PM by Eric Lippert | 62 Comments Filed under: Scripting, Performance, Recursion