Discussion on: What are your favorite books?

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Replies for: Thanks for the author list! I've heard good things about Eloquent Ruby - it's definitely on the list if I keep exploring the language. The mazes ...

Could you share some example code of mazes book so let us know if we can understand it?

Sure, here's a partial (but functional) implementation of the Cell class used in the book. It is not advanced Ruby, but the author does not spend any time teaching Ruby concepts - this code snippet appears early on in the first chapter and the assumption is the reader can understand it:

class Cell
  attr_reader :row, :column
  attr_accessor :north, :south, :east, :west

  def initialize(row, column)
    @row, @column = row, column
    @links = {}
  end

  def link(cell, bidi=true)
    @links[cell] = true
    cell.link(self, false) if bidi
    self
  end

  def unlink(cell, bidi=true)
    @links.delete(cell)
    cell.unlink(self, false) if bidi
    self
  end

  def links
    @links.keys
  end

  def linked?(cell)
    @links.key?(cell)
  end

  def neighbors
    list = []
    list << north if north
    list << south if south
    list << east if east
    list << west if west
    list
  end
end

And the simplest algorithm:


class BinaryTree
  def self.on(grid)
    grid.each_cell do |cell|
      neighbors = []
      neighbors << cell.north if cell.north
      neighbors << cell.east if cell.east

      index = rand(neighbors.length)
      neighbor = neighbors[index]

      cell.link(neighbor) if neighbor
    end

    grid
  end
end

Basic building blocks, but you do need to know what, for example, attr_accessor means

I'm following along in TypeScript and finding the translation straightforward.

chenge • Nov 7 '18

Thanks, I almost understand it.