# TITLE:
#
#   String Bracketing Extensoins
#
# SUMMARY:
#
#   String extension methods which enclose on unenclose a striong.
#
# CREDITS:
#
#   - Thomas Sawyer

#
class String

  BRA2KET = { '['=>']', '('=>')', '{'=>'}', '<'=>'>' }

  # Return a new string embraced by given brakets.
  # If only one bracket char is given it will be placed
  # on either side.
  #
  #   "wrap me".bracket('{')        #=> "{wrap me}"
  #   "wrap me".bracket('--','!')   #=> "--wrap me!"

  def bracket(bra, ket=nil)
    #ket = String.bra2ket[$&] if ! ket && /^[\[({<]$/ =~ bra
    ket = BRA2KET[bra] unless ket
    "#{bra}#{self}#{ket ? ket : bra}"
  end

  # Inplace version of #braket.

  def bracket!(bra, ket=nil)
    self.replace(bracket(bra, ket))
  end

  # Return a new string embraced by given brakets.
  # If only one bracket char is given it will be placed
  # on either side.
  #
  #   "{unwrap me}".debracket('{')        #=> "unwrap me"
  #   "--unwrap me!".debracket('--','!')  #=> "unwrap me!"

  def unbracket(bra=nil, ket=nil)
    if bra
      ket = BRA2KET[bra] unless ket
      ket = ket ? ket : bra
      s = self.dup
      s.gsub!(%r[^#{Regexp.escape(bra)}], '')
      s.gsub!(%r[#{Regexp.escape(ket)}$], '')
      return s
    else
      if m = BRA2KET[ self[0,1] ]
        return self.slice(1...-1) if self[-1,1]  == m
      end
    end
    return self.dup  # if nothing else
  end

  # Inplace version of #debraket.

  def unbracket!(bra=nil, ket=nil)
    self.replace( unbracket(bra, ket) )
  end

  # Return a new string embraced by given quotes.
  # If no quotes are specified, then assumes single quotes.
  #
  #   "quote me".quote     #=> "'quote me'"
  #   "quote me".quote(2)  #=> "\"quote me\""

  def quote(type=:s)
    case type.to_s.downcase
    when 's', 'single'
      bracket("'")
    when 'd', 'double'
      bracket('"')
    when 'b', 'back'
      bracket('`')
    else
      bracket("'")
    end
  end

  # Remove quotes from string.

  def dequote
    s = self.dup

    case self[0,1]
    when "'", '"', '`'
      s[0] = ''
    end

    case self[-1,1]
    when "'", '"', '`'
      s[-1] = ''
    end

    return s
  end
end



#  _____         _
# |_   _|__  ___| |_
#   | |/ _ \/ __| __|
#   | |  __/\__ \ |_
#   |_|\___||___/\__|
#
=begin test

  require 'test/unit'

  class TestStringBracket < Test::Unit::TestCase

    def test_bracket
      assert_equal( '#X#', 'X'.bracket('#') )
      assert_equal( 'xX!', 'X'.bracket('x','!') )
      assert_equal( '{X}', 'X'.bracket('{','}') )
      assert_equal( '<X>', 'X'.bracket('<') )
      assert_equal( '(X)', 'X'.bracket('(') )
      assert_equal( '[X]', 'X'.bracket('[') )
      assert_equal( '{X}', 'X'.bracket('{') )
    end

    def test_braket!
      a = 'X' ; a.bracket!('#')
      assert_equal( '#X#', a )
      a = 'X' ; a.bracket!('x','!')
      assert_equal( 'xX!', a )
      a = 'X' ; a.bracket!('{','}')
      assert_equal( '{X}', a )
      a = 'X' ; a.bracket!('<')
      assert_equal( '<X>', a )
      a = 'X' ; a.bracket!('(')
      assert_equal( '(X)', a )
      a = 'X' ; a.bracket!('[')
      assert_equal( '[X]', a )
      a = 'X' ; a.bracket!('{')
      assert_equal( '{X}', a )
    end

    def test_quote_01
      a =  "hi"
      assert_raises( ArgumentError ) { a.quote(1,2) }
    end

    def test_quote_02
      a =  "hi"
      assert_equal( %{'hi'}, a.quote )
    end

    def test_quote_03
      a =  "hi"
      assert_equal( %{"hi"}, a.quote(:d) )
      assert_equal( %{"hi"}, a.quote(:double) )
    end

    def test_quote_04
      a =  "hi"
      assert_equal( %{'hi'}, a.quote(:s) )
      assert_equal( %{'hi'}, a.quote(:single) )
    end

    def test_quote_05
      a =  "hi"
      assert_equal( %{`hi`}, a.quote(:b) )
      assert_equal( %{`hi`}, a.quote(:back) )
    end

  end

=end