Expr Power(Expr val, BigInteger pow) {
if(pow == BigInteger.One)
return val;
return val.MatchDefault(
@default: x => builder.Power(x, pow),
@const: x => Const(BigRational.Pow(x, pow)),
mult: args => Mult(args.Select(x => Power(x, pow)).ToExprList()),
power: (v, p) => builder.Power(v, pow * p)
);
}
public static UnaryExpressionInfo ExtractMultiplyUnaryInfo(Expr expr)
{
Func<Expr, UnaryExpressionInfo> getDefault = x => GetDefault(BinaryOperation.Multiply, x);
Func<BigRational, UnaryExpressionInfo> getConstant = x => Constant(BinaryOperation.Multiply, x);
return expr.MatchDefault(
getDefault,
@const: getConstant
);
}
public static UnaryExpressionInfo ExtractAddUnaryInfo(Expr expr)
{
Func<Expr, UnaryExpressionInfo> getDefault = x => GetDefault(BinaryOperation.Add, x);
Func<BigRational, UnaryExpressionInfo> getConstant = x => Constant(BinaryOperation.Add, x);
return expr.MatchDefault(
getDefault,
mult: args => {
var headConstant = args.First().AsConst();
if(headConstant.Return(x => x < 0, () => false)) {
var exprConstant = ExprExtensions.Const(-headConstant.Value);
var tail = GetTail(args);
Expr expr2 = (headConstant.Value == BigInteger.MinusOne) ?
tail :
Builder.Simple.Multiply(exprConstant.Yield().Concat(tail.ToMult()).ToExprList());
return new UnaryExpressionInfo(expr2, BinaryOperationEx.Subtract);
}
return getDefault(Builder.Simple.Multiply(args.ToExprList()));
},
@const: getConstant
);
}
