public TreeNode Reduce(TreeNode node)
{
if (!(node is Application application))
{
return(node);
}
if (!(application.Func is T))
{
return(node);
}
return(ReduceImpl(AstReducer.Reduce(application.Arg)) ?? node);
}
private void RunTest(string input, string output)
{
var ast =
new AstParser(new FunctionDeclarationsFactory()).Parse(input);
var reduced = AstReducer.Reduce(ast);
var expected =
new AstParser(new FunctionDeclarationsFactory()).Parse(output);
Console.WriteLine("<<<<<<<<Input ast>>>>>>>>");
Console.WriteLine(ast.PrettyPrint());
Console.WriteLine("<<<<<<<<Reduced ast>>>>>>>>");
Console.WriteLine(reduced.PrettyPrint());
Console.WriteLine("<<<<<<<<Expected ast>>>>>>>>");
Console.WriteLine(expected.PrettyPrint());
Assert.AreEqual(output, reduced.Print());
}
public TreeNode Reduce(TreeNode node)
{
//ap (ap (ap if0 0) x1) x2 = x0
if (node is Application a1 &&
a1.Func is Application a2 &&
a2.Func is Application a3 &&
a3.Func is IfZero)
{
var arg = AstReducer.Reduce(a3.Arg);
if (arg is Number number)
{
return(number.Value == 0 ? a2.Arg : a1.Arg);
}
}
return(node);
}
public TreeNode Reduce(TreeNode node)
{
if (!(node is Application application))
{
return(node);
}
if (!(application.Func is IsNil))
{
return(node);
}
var arg = AstReducer.Reduce(application.Arg);
if (arg is Nil)
{
return(True.Instance);
}
return(False.Instance);
}
public void Test1()
{
var x = "ap ap s s ap ap ap s t x0 x1";
Console.WriteLine(AstReducer.Reduce(new AstParser(new FunctionDeclarationsFactory()).Parse(x)).PrettyPrint());
}
