Depth-first search in APL

Dyalog · 10.7K views · 2014-07-18 · 11:32

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Overview

John Scholes builds a depth-first tree-search operator step by step in a Dyalog APL session. It covers higher-order functions and runs the search on the N-Queens problem.

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HN commenters call it a beautiful, brilliant demonstration of APL's expressiveness and a model of clear narration.

Recommended by 2 HN people across 3 months · HN mentions 2019–2021

Topics

Functional programming Algorithms & data structures

What people said

geocar · 2021-12 · Strong recommendation
You might like looking at how Dyalog handles higher-order functions; John Scholes really put this beautiful presentation together about using them as a depth-first search reusable function [VIDEO] and if you haven't seen it, you should!
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paliilap · 2019-08 · Strong recommendation
That 1975 APL demonstration is lovely. Much has been preserved in Dyalog and GNU APL - it's very interesting to see how timeless the core APL functions are. I'm very fond of a number of videos by the late John Scholes narrating APL solutions step by step, including the well-known demonstration of Conway's Game of Life in APL (0). His videos on depth-first search (1) and solving sudoku (2) are also brilliant. (0) [LINK] (1) [VIDEO] (2) [LINK]
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geocar · 2019-07 · Strong recommendation
APL is great. If you haven't seen them, the late John Scholes did a number of absolutely beautiful demonstrations programming in APL[1], [2], [3]. [1]: [VIDEO] [2]: [LINK] [3]: [LINK]
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Sources

Video by Dyalog, played through YouTube.

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