public Addition (Expression left, Expression right) : base(left, right)
{
}
public Subtraction (Expression left, Expression right) : base(left, right)
{
}
public AssignmentFunction (string id, string[] parameters, Expression body)
{
Id = id;
Parameters = parameters;
Body = body;
}
public Division (Expression left, Expression right) : base(left, right)
{
}
private Func<double> Compile (Expression expression)
{
if (expression is Const)
return () => (expression as Const).Value;
if (expression is Addition) {
var addition = expression as Addition;
var left = Compile (addition.Left);
var right = Compile (addition.Right);
return () => left () + right ();
}
if (expression is Subtraction) {
var subtraction = expression as Subtraction;
var left = Compile (subtraction.Left);
var right = Compile (subtraction.Right);
return () => left () - right ();
}
if (expression is Multiplication) {
var multiplication = expression as Multiplication;
var left = Compile (multiplication.Left);
var right = Compile (multiplication.Right);
return () => left () * right ();
}
if (expression is Division) {
var division = expression as Division;
var left = Compile (division.Left);
var right = Compile (division.Right);
return () => left () / right ();
}
if (expression is Variable) {
var variable = expression as Variable;
return () =>
{
return CurrentScope.GetVariable (variable.Id);
};
}
if (expression is Function) {
var function = expression as Function;
var arg_list = function.Args.Select (arg => Compile (arg)).ToList ();
return () =>
{
var func = functions.FirstOrDefault (f => f.Id == function.Id && f.Parameters.Count () == arg_list.Count);
if (func == null)
return 0;
var parentScope = CurrentScope;
CurrentScope = new Scope () { Parent = parentScope};
var i = 0;
foreach (var p in func.Parameters) {
var value = arg_list [i] ();
CurrentScope.SetVariable (p, value);
i++;
}
var result = func.Body ();
CurrentScope.Parent = null;
CurrentScope = parentScope;
return result;
};
}
return null;
}
public AssignmentVariable (string id, Expression expression)
{
Id = id;
Expression = expression;
}
public BinaryOperation (Expression left, Expression right)
{
Left = left;
Right = right;
}
public ExpressionStatement (Expression expression)
{
Expression = expression;
}
public Function (string id, Expression[] args)
{
Id = id;
Args = args;
}
public Multiplication (Expression left, Expression right) : base(left, right)
{
}