/// <summary>
/// Reduces the pattern by applying it the specified object.
/// </summary>
/// <param name="object">The object to match the pattern against.</param>
/// <returns>The expression representing the pattern applied to the specified object.</returns>
internal override Expression Reduce(Expression @object)
{
if (Value.Value == null)
{
// REVIEW: Value types, nullable value types, etc.
// Ensure no operator== is called.
return(Expression.Equal(Expression.Convert(@object, typeof(object)), ConstantNull));
}
else
{
MethodInfo CheckNaN() => Value.Value switch
{
float f when float.IsNaN(f) => FloatIsNaN,
double d when double.IsNaN(d) => DoubleIsNaN,
_ => null
};
var checkNaN = CheckNaN();
if (checkNaN != null)
{
return(Expression.Call(checkNaN, @object));
}
return(RelationalCSharpPattern.MakeTest(this, @object, ExpressionType.Equal, Value));
}
}
/// <summary>
/// Creates a relational pattern that compares against a constant value.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="type">The type of the pattern.</param>
/// <param name="value">The value to compare with.</param>
/// <returns>A <see cref="RelationalCSharpPattern" /> representing a relational pattern.</returns>
public static RelationalCSharpPattern Relational(CSharpPatternInfo info, CSharpPatternType type, ConstantExpression value)
{
switch (type)
{
case CSharpPatternType.LessThan:
case CSharpPatternType.LessThanOrEqual:
case CSharpPatternType.GreaterThan:
case CSharpPatternType.GreaterThanOrEqual:
return(RelationalCSharpPattern.Make(info, type, value));
default:
throw Error.InvalidRelationalPatternType(type);
}
}
protected internal virtual CSharpPattern VisitRelationalPattern(RelationalCSharpPattern node) =>
node.Update(
VisitAndConvert(node.Value, nameof(VisitRelationalPattern))
);
/// <summary> /// Creates a relational greater than or equal pattern that compares against a constant value. /// </summary> /// <param name="info">Type information about the pattern.</param> /// <param name="value">The value to compare with.</param> /// <returns>A <see cref="RelationalCSharpPattern" /> representing a relational pattern.</returns> public static RelationalCSharpPattern GreaterThanOrEqual(CSharpPatternInfo info, ConstantExpression value) => RelationalCSharpPattern.Make(info, CSharpPatternType.GreaterThanOrEqual, value);
/// <summary> /// Creates a relational less than pattern that compares against a constant value. /// </summary> /// <param name="info">Type information about the pattern.</param> /// <param name="value">The value to compare with.</param> /// <returns>A <see cref="RelationalCSharpPattern" /> representing a relational pattern.</returns> public static RelationalCSharpPattern LessThan(CSharpPatternInfo info, ConstantExpression value) => RelationalCSharpPattern.Make(info, CSharpPatternType.LessThan, value);