Ruby/String/String class Extension

class String
  def substitute(binding=TOPLEVEL_BINDING)
    eval(%{"#{self}"}, binding)
  end
end
template = %q{static string #{food}!}
food = "b"
template.substitute(binding)         
food = "p"
template.substitute(binding)

class String
  def pop
    return nil if self.empty?
    item=self[-1]
    self.chop!
    return nil if item.nil?
    item.chr
  end
  def unshift(other)
    newself = other.to_s.dup.pop.to_s + self
    self.replace(newself)
  end
end
a = "this is a test"
puts (a.unshift "asfd")

class String 
  def unshift_word(other)
    newself = other.to_s + self
    self.replace(newself)
  end
end
a = "this is a test"
puts a.unshift_word "another"

class String
  def bin
    val = self.strip
    pattern = /^([+-]?)(0b)?([01]+)(.*)$/
    parts = pattern.match(val)
    return 0 if not parts
    sign = parts[1]
    num  = parts[3]
    eval(sign+"0b"+num)
  end
end
a = "10011001".bin
b = "0b10011001".bin
c = "0B1001001".bin
d = "nothing".bin
e = "0b100121001".bin

class String
  def acronym(thresh=0)
    acro=""
    str=self.dup.strip
    while !str.nil? && !str.empty?
      word = str.shift_word
      if word.length >= thresh
        acro += word.strip[0,1].to_s.upcase
      end
    end
    acro
  end
  @@first_word_re = /^(\w+\W*)/
  def shift_word
    return nil if self.empty?
    self=~@@first_word_re
    newself= $" || ""       # $" is POSTMATCH
    self.replace(newself) unless $".nil?
    $1
  end
end
 
s1 = "this is a test"
puts s1.acronym

class String
  def scramble
    (split //).sort_by { rand }.join
  end
end
 
class UnpredictableString < String
  def scramble
    (split //).sort_by { rand }.join
  end
  def inspect
    scramble.inspect
  end
end
str = UnpredictableString.new("this is a test.")
puts str

class String
  @@last_word_re = /(\w+\W*)$/
  def pop_word
    return nil if self.empty?
    self=~@@last_word_re
    newself= $" || ""       # $" is PREMATCH
    self.replace(newself) unless $".nil?
    $1
  end
end
 
a = "this is a test"
puts a.pop_word "another"

class String
  def pop
    return nil if self.empty?
    item=self[-1]
    self.chop!
    return nil if item.nil?
    item.chr
  end
end
a = "this is a test"
puts a.pop

class String
  def word_count
    frequencies = Hash.new(0)
    downcase.scan(/\w+/) { |word| frequencies[word] += 1 }
   return frequencies
  end
end
%{Dogs dogs dog dog dogs.}.word_count

class String
  def push(other)
    newself = self + other.to_s.dup.shift.to_s
    self.replace(newself)
  end
  def shift
    return nil if self.empty?
    item=self[0]
    self.sub!(/^./,"")
    return nil if item.nil?
    item.chr
  end
end
a = "this is a test"
puts (a.push "another")

class String
  def push_word(other)
    newself = self + other.to_s
    self.replace(newself)
  end
end
a = "this is a test"
puts a.push_word "another"

class String
  alias old_compare <=>
  def <=>(other)
    a = self.dup
    b = other.dup
    # Remove punctuation
    a.gsub!(/\,\.\?\!\:\;/, "")
    b.gsub!(/\,\.\?\!\:\;/, "")
    # Remove initial articles
    a.gsub!(/(a |an |the )/i, "")
    b.gsub!(/(a |an |the )/i, "")
    # Remove leading/trailing whitespace
    a.strip!
    b.strip!
    # Use the old <=>
    a.old_compare(b)
  end
end
 
title1 = "Calling All Cars"
title2 = "The Call of the Wild"
# Ordinarily this would print "yes"
if title1 < title2
  puts "yes"
else
  puts "no"         # But now it prints "no"
end

class String
  def shift
    return nil if self.empty?
    item=self[0]
    self.sub!(/^./,"")
    return nil if item.nil?
    item.chr
  end
end
a = "this is a test"
puts a.shift

class String
  def mgsub(key_value_pairs=[].freeze)
    regexp_fragments = key_value_pairs.collect { |k,v| k }
    gsub(Regexp.union(*regexp_fragments)) do |match|
      key_value_pairs.detect{|k,v| k =~ match}[1]
    end
  end
end
"GO HOME!".mgsub([[/.*GO/i, "Home"], [/home/i, "is where the heart is"]])
# => "Home is where the heart is!"
"Here is number #123".mgsub([[/[a-z]/i, "#"], [/#/, "P"]])
# => "#### ## ###### P123"
"between".mgsub([[/ee/, "AA"], [/e/, "E"]])      # Good code
# => "bEtwAAn"

class String
  def rotate_left(n=1)
    n=1 unless n.kind_of? Integer
    n.times do
      char = self.shift
      self.push(char)
    end
    self
  end
  def push(other)
    newself = self + other.to_s.dup.shift.to_s
    self.replace(newself)
  end
  def shift
    return nil if self.empty?
    item=self[0]
    self.sub!(/^./,"")
    return nil if item.nil?
    item.chr
  end
end
a = "this is a test"
puts a.rotate_left

class String
  def rotate_right(n=1)
    n=1 unless n.kind_of? Integer
    n.times do
      char = self.pop
      self.unshift(char)
    end
    self
  end
  def pop
    return nil if self.empty?
    item=self[-1]
    self.chop!
    return nil if item.nil?
    item.chr
  end
  def unshift(other)
    newself = other.to_s.dup.pop.to_s + self
    self.replace(newself)
  end  
end
a = "this is a test"
puts a.rotate_right

class String 
  @@first_word_re = /^(\w+\W*)/
  def shift_word
    return nil if self.empty?
    self=~@@first_word_re
    newself= $" || ""       # $" is POSTMATCH
    self.replace(newself) unless $".nil?
    $1
  end
end 
 
a = "this is a test"
puts a.shift_word

class String
  def rot13
    self.tr("A-Ma-mN-Zn-z","N-Zn-zA-Ma-m")
  end
end
joke = "Y2K bug"
joke13 = joke.rot13    # "L2X oht"

class String
  def vowels
    self.scan(/[aeiou]/i)
  end
end
puts "This is a test".vowels.join("-")

class String
  def scramble
    (split //).sort_by { rand }.join
  end
end
puts "I once was a normal string.".scramble