public void TestFlatten()
{
ParserMonad <ParserMonad <int> > p = text => {
var first = text[0];
if (first == 'a')
{
return(Tuple.Create <ParserMonad <int>, string>(
rest => Tuple.Create(int.Parse(rest.Substring(0, 5)), rest.Substring(5)),
text.Substring(1)));
}
return(Tuple.Create(ParserMonad.Wrap(-1), text.Substring(1)));
};
var q = p.Flatten();
q("a00004x").AssertEquals(Tuple.Create(4, "x"));
q("b00004x").AssertEquals(Tuple.Create(-1, "00004x"));
}
public void TestWrap()
{
var s = ParserMonad.Wrap("test");
s("whatever").AssertEquals(Tuple.Create("test", "whatever"));
}