protected override Symbol ReduceImplementation(ReductionContext context, Identifier identifier)
{
Symbol
operandA = context.Reduce(identifier.Tail[0]),
operandB = context.Reduce(identifier.Tail[1]);
return(new Literal <bool>(operandA.Equals(operandB)));
}
protected override Symbol ReduceImplementation(ReductionContext context, Identifier identifier)
{
Symbol reducedFirstSymbol = context.Reduce(identifier.Tail[0]);
bool boolean = context.BooleanConverter.Convert(reducedFirstSymbol);
return(boolean
? reducedFirstSymbol
: identifier.Tail[1]);
}
protected override Symbol ReduceImplementation(ReductionContext context, Identifier identifier)
{
Symbol result = null;
foreach (Symbol symbol in identifier.Tail)
{
result = context.Reduce(symbol);
}
return(result);
}
public Symbol Reduce(ReductionContext context, Symbol s)
{
Symbol current = s;
for (var i = 0; i < _reducers.Length; i++)
{
Symbol newSymbol = context.Reduce(current, _reducers[i]);
if (newSymbol.Equals(current))
{
continue;
}
i = -1;
current = newSymbol;
}
return(current);
}
protected override Symbol ReduceImplementation(ReductionContext context, Identifier identifier)
{
decimal GetOperand(int index) => context.NumbersConverter.Convert(context.Reduce(identifier.Tail[index]));
Lazy <decimal>
operandA = new Lazy <decimal>(() => GetOperand(0)),
operandB = new Lazy <decimal>(() => GetOperand(1));
decimal?value = identifier.Name switch
{
nameof(Add) => (decimal?)operandA.Value + operandB.Value,
nameof(Sub) => operandA.Value - operandB.Value,
nameof(Mul) => operandA.Value * operandB.Value,
nameof(Div) => operandA.Value / operandB.Value,
_ => null
};
return(value is null
? null
: new Literal <decimal>(value.Value));
}
}
public static void Main(string[] args)
{
var ctx = new ReductionContext(
new BuiltInsReducer()
);
Identifier n = I("n"), Fact = I("Fact");
Symbol res = ctx.Reduce(
Let(Fact)[
Func(n)[
If[n][
Mul[n][
Fact[
ReduceFirst[Sub[n][1]]
]
]
][1]
]
][10]
);
Console.WriteLine(res);
}