require 'test/unit'
require 'rx5'

class TestDq2Sq < Test::Unit::TestCase

  def test_noquotes
    assert_equal("", dq2sq(''))
    assert_equal("abc", dq2sq('abc'))
  end

  def test_single_pair
    assert_equal("''", dq2sq('""'))
    assert_equal("foo='bar'", dq2sq('foo="bar"'))
    assert_equal("'foo'=bar", dq2sq('"foo"=bar'))
    assert_equal("abc'def'ghi", dq2sq('abc"def"ghi'))
  end

  def test_multi_pairs
    assert_equal("'foo'=\"bar\"", dq2sq('"foo"="bar"'))
    assert_equal("a'b'c\"d\"e", dq2sq('a"b"c"d"e'))
    assert_equal("''\"\"", dq2sq('""""'))
  end

  def test_mixed_pairs
    assert_equal("'foo'='bar'", dq2sq('"foo"=\'bar\''))
    assert_equal("'foo'='bar'", dq2sq('\'foo\'="bar"'))
  end

  def test_unmached_quote
    assert_equal("x\"y", dq2sq('x"y'))
    assert_equal("x\"\'y", dq2sq('x"\'y'))
    assert_equal("x'y'z\"u", dq2sq('x"y"z"u'))
  end

end

def dq2sq(str)
  # fill here
end

def dq2sq(str)
  return subst(str, [:cat, [:lit, "\""],[:cat, [:rep_lazy, [:anysym]], [:lit, "\""]]]){|s, h| "'#{s[1...(s.size - 1)]}'" }
end