What happened to my Sunday evening, a programming story about geocaching (sorta.)

gistfile1.rb

# My sister and brother inlaw got into geocaching 
# after I showed them the android app for it... anyhow I was in Olympia for my m
# oms birthday and I showed them that puzzle cache (http://coord.info/GC1JD07)... 
# and when my manual math ended up being off by one in my "B" calculation  (21-19 
# != 3) I uh, got carried away once I got back to seattle.  :(

# I only got this carried away though 'cause I'm trying to build a presentation 
# on parsers for a conference and I thought this was a reasonable mini language wh
# ere I could show the "quick" hour long solution I came up with versus the actual
# parser one I'll present.  I also could've done this faster by just coding this 
# like program, but I wanted to try to make it more like a programming language...
# and if you took the real example code straight from what they gave you, it woul
# dn't work because some of the variables would've still been undefined, so I  nee
# ded to reorder them. :P  I'm a dork.

# Wes

# START THE CODES 
#! ruby

clue = "humptydumpty"
forumulas = %q{
@a = send(:"1st letter") * 0
@b = send(:"2nd letter") - 19
@c = @a * @b
@d = send(:"3rd letter") - 4
@e = send(:"4th letter") - send(:"9th letter")
@f = send(:"12th letter") - send(:"5th letter")
@j = send(:"12th letter") - (@d + @d)
@h = send(:"2nd letter") - send(:"11th letter")
@g = @j - @h
@i = send(:"7th letter") + 1
@report = %( N  47 #{@a}#{@b}.#{@c}#{@d}#{@e} \n W 122 #{@f}#{@g} #{@h}#{@i}#{@j} \n)
}

PuzzleCacheLang.solve clue, forumulas

# Outputs....
#
# [wesmaldonado@wombatbadger:~/workspace/puzzle-cache-lang]  $ ruby pcl.rb 
# N  47 02.093 
# W 122 56 157 

# ---- http://about.me/wesmaldonado ----
# twitter ::  http://twitter.com/wes

class PuzzleCacheLang

  attr_accessor :clue
  attr_reader :letter_position
  attr_accessor :solver

  def initialize(clue)
    self.clue = clue
    @letter_position = {}
    ('a'..'z').to_a.each_with_index.map { |x, i| @letter_position[x] = i+1 }
    @clue_to_alpha_value = clue.split("").map { |l| @letter_position[l] }
    self
  end

  def method_missing(meth, *args)
    if meth.to_s =~ /^(\d+)\w{2}\s+letter/
      @clue_to_alpha_value[$1.to_i - 1]
    end
  end

  def self.woo
    self.solve("humptydumpty",%q{ @i = send(:"7th letter") + 1 })
  end

  def self.solve clue, formulas
    solver = PuzzleCacheLang.new(clue)
    formulas.split("\n").each do |f|
      next if f.length == 0
      exp = "eval(' #{f} ')"
      begin
        solver.instance_eval exp
      rescue => e
        self.report(solver, exp, e)
      end
    end
    puts solver.instance_variable_get :@report
    solver
  end

  def self.report(s, exp, ex)
    puts "exp was: #{exp}"
    puts "Error was #{ex.message}"
    s.instance_variables.each do |iv|
      puts "#{iv} => " +  s.instance_variable_get(iv).inspect
    end
    exit
  end
end

clue = "humptydumpty"
forumulas = %q{
@a = send(:"1st letter") * 0
@b = send(:"2nd letter") - 19
@c = @a * @b
@d = send(:"3rd letter") - 4
@e = send(:"4th letter") - send(:"9th letter")
@f = send(:"12th letter") - send(:"5th letter")
@j = send(:"12th letter") - (@d + @d)
@h = send(:"2nd letter") - send(:"11th letter")
@g = @j - @h
@i = send(:"7th letter") + 1
@report = %( N  47 #{@a}#{@b}.#{@c}#{@d}#{@e} \n W 122 #{@f}#{@g} #{@h}#{@i}#{@j} \n)
}

PuzzleCacheLang.solve clue, forumulas

#Outputs....

#[wesmaldonado@wombatbadger:~/workspace/puzzle-cache-lang]  $ ruby pcl.rb 
# N  47 02.093 
# W 122 56 157 

The thing that makes this a possible language/parser candidate is that the puzzle language is moderately consistant. Letters get translated to the position in the alphabets, elements use short letter abbreviations to their atomic numbers or weights, etc. And there are phrases like "2nd letter from each X" things like that. Simple transforms overall.