internal ITupleCSharpPattern(CSharpPatternInfo info, MethodInfo getLengthMethod, MethodInfo getItemMethod, ReadOnlyCollection <PositionalCSharpSubpattern> deconstruction)
: base(info)
{
GetLengthMethod = getLengthMethod;
GetItemMethod = getItemMethod;
Deconstruction = deconstruction;
}
internal BinaryCSharpPattern(CSharpPatternInfo info, CSharpPatternType patternType, CSharpPattern left, CSharpPattern right)
: base(info)
{
PatternType = patternType;
Left = left;
Right = right;
}
/// <summary>
/// Creates a pattern that always matches and assigns the input to a variable.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="variable">The variable to assign to.</param>
/// <returns>A <see cref="DiscardCSharpPattern" /> that represents a pattern that always matches.</returns>
public static VarCSharpPattern Var(CSharpPatternInfo info, ParameterExpression variable)
{
RequiresNotNull(variable, nameof(variable));
info ??= PatternInfo(variable.Type, variable.Type);
return(Var(ObjectPatternInfo(info, variable)));
}
/// <summary>
/// Creates a pattern that checks convertibility to a type and assigns to a variable.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="variable">The variable to assign to.</param>
/// <returns>A <see cref="DeclarationCSharpPattern" /> that represents a pattern that checks convertibility to a type and assigns to a variable.</returns>
public static DeclarationCSharpPattern Declaration(CSharpPatternInfo info, ParameterExpression variable)
{
RequiresNotNull(variable, nameof(variable));
info ??= PatternInfo(variable.Type, variable.Type);
return(Declaration(ObjectPatternInfo(info, variable), variable.Type));
}
/// <summary>
/// Creates an and pattern with the specified left and right patterns.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="left">The left pattern.</param>
/// <param name="right">The right pattern.</param>
/// <returns>A <see cref="NotCSharpPattern" /> representing an and pattern.</returns>
public static BinaryCSharpPattern And(CSharpPatternInfo info, CSharpPattern left, CSharpPattern right)
{
RequiresNotNull(left, nameof(left));
RequiresNotNull(right, nameof(right));
info ??= PatternInfo(left.InputType, right.NarrowedType);
RequiresCompatiblePatternTypes(info.InputType, ref left);
RequiresCompatiblePatternTypes(left.NarrowedType, ref right);
RequiresCompatiblePatternTypes(right.NarrowedType, info.NarrowedType);
return(new BinaryCSharpPattern(info, CSharpPatternType.And, left, right));
}
/// <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);
}
}
/// <summary>
/// Creates a pattern that always matches.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <returns>A <see cref="DiscardCSharpPattern" /> that represents a pattern that always matches.</returns>
public static DiscardCSharpPattern Discard(CSharpPatternInfo info)
{
if (info != null)
{
if (info.InputType != info.NarrowedType)
{
throw Error.PatternInputAndNarrowedTypeShouldMatch(nameof(CSharpPatternType.Discard));
}
}
else
{
info = PatternInfo(typeof(object), typeof(object));
}
return(new DiscardCSharpPattern(info));
}
/// <summary>
/// Creates an object holding type information about a pattern.
/// </summary>
/// <param name="info">The underlying type information.</param>
/// <param name="variable">The CSharpObjectPatternInfo to assign to upon successfully matching the associated pattern.</param>
/// <returns>A <see cref="CSharpPatternInfo" /> object holding type information about a pattern.</returns>
public static CSharpObjectPatternInfo ObjectPatternInfo(CSharpPatternInfo info, ParameterExpression variable)
{
info ??= PatternInfo(typeof(object), variable?.Type ?? typeof(object));
if (variable != null)
{
if (variable.Type.IsByRef)
{
throw LinqError.VariableMustNotBeByRef(variable, variable.Type);
}
RequiresCompatiblePatternTypes(info.NarrowedType, variable.Type);
}
return(new CSharpObjectPatternInfo(info, variable));
}
internal static RelationalCSharpPattern Make(CSharpPatternInfo info, CSharpPatternType type, ConstantExpression value)
{
RequiresNotNull(value, nameof(value));
CheckConstant(value, isRelational: true);
if (info != null)
{
RequiresCompatiblePatternTypes(value.Type, info.NarrowedType);
}
else
{
info = PatternInfo(typeof(object), value.Type);
}
return(new RelationalCSharpPattern(info, type, value));
}
/// <summary>
/// Creates a pattern that checks convertibility to a type.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="type">The type to check for.</param>
/// <returns>A <see cref="TypeCSharpPattern" /> that represents a pattern that checks for a type.</returns>
public static TypeCSharpPattern Type(CSharpPatternInfo info, Type type)
{
RequiresNotNull(type, nameof(type));
ValidatePatternType(type);
if (info != null)
{
RequiresCompatiblePatternTypes(type, info.NarrowedType);
}
else
{
info = PatternInfo(typeof(object), type);
}
return(new TypeCSharpPattern(info, type));
}
/// <summary>
/// Creates a constant pattern that checks for equality with the given constant value.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="value">The value used for the constant check.</param>
/// <returns>A <see cref="ConstantCSharpPattern" /> representing a constant pattern.</returns>
public static ConstantCSharpPattern Constant(CSharpPatternInfo info, ConstantExpression value)
{
RequiresNotNull(value, nameof(value));
CheckConstant(value, isRelational: false);
if (info != null)
{
var inputType = value.Value == null ? info.InputType : value.Type;
RequiresCompatiblePatternTypes(inputType, info.NarrowedType);
}
else
{
info = PatternInfo(typeof(object), value.Type);
}
return(new ConstantCSharpPattern(info, value));
}
/// <summary>
/// Creates a negated pattern.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="negated">The pattern to negate.</param>
/// <returns>A <see cref="NotCSharpPattern" /> representing a negated pattern.</returns>
public static NotCSharpPattern Not(CSharpPatternInfo info, CSharpPattern negated)
{
RequiresNotNull(negated, nameof(negated));
if (info != null)
{
if (info.InputType != info.NarrowedType)
{
throw Error.PatternInputAndNarrowedTypeShouldMatch(nameof(CSharpPatternType.Not));
}
RequiresCompatiblePatternTypes(info.InputType, ref negated);
}
else
{
info = PatternInfo(negated.InputType, negated.InputType);
}
return(new NotCSharpPattern(info, negated));
}
// TODO: Add convenience overloads.
/// <summary>
/// Creates a slice pattern.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="indexerAccess">The <see cref="LambdaExpression"/> representing the indexer access used to retrieve a slice from the collection.</param>
/// <param name="pattern">The <see cref="CSharpPattern"/> representing the optional pattern to apply to the slice.</param>
/// <returns>A <see cref="SliceCSharpPattern" /> representing a slice pattern.</returns>
public static SliceCSharpPattern Slice(CSharpPatternInfo info, LambdaExpression indexerAccess, CSharpPattern pattern)
{
RequiresNotNull(info, nameof(info));
var collectionType = info.InputType;
if (indexerAccess != null)
{
RequiresCanRead(indexerAccess, nameof(indexerAccess));
if (indexerAccess.Parameters.Count != 2)
{
throw Error.IndexerAccessShouldHaveTwoParameters();
}
if (!AreEquivalent(indexerAccess.Parameters[0].Type, collectionType))
{
throw Error.IndexerAccessFirstParameterShouldHaveCollectionType(collectionType);
}
if (indexerAccess.Parameters[1].Type != typeof(Range))
{
throw Error.IndexerAccessSecondParameterInvalidType(typeof(Range));
}
if (indexerAccess.ReturnType == typeof(void))
{
throw Error.ElementTypeCannotBeVoid();
}
}
if (pattern != null)
{
RequiresNotNull(indexerAccess, nameof(indexerAccess));
RequiresCompatiblePatternTypes(indexerAccess.ReturnType, ref pattern);
RequiresCompatiblePatternTypes(pattern.NarrowedType, info.NarrowedType);
}
return(new SliceCSharpPattern(info, indexerAccess, pattern));
}
/// <summary>
/// Creates an or pattern with the specified left and right patterns.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="left">The left pattern.</param>
/// <param name="right">The right pattern.</param>
/// <returns>A <see cref="NotCSharpPattern" /> representing an or pattern.</returns>
public static BinaryCSharpPattern Or(CSharpPatternInfo info, CSharpPattern left, CSharpPattern right)
{
RequiresNotNull(left, nameof(left));
RequiresNotNull(right, nameof(right));
RequiresCompatiblePatternTypes(left.InputType, ref right);
if (info == null)
{
var inputType = left.InputType;
var narrowedType = FindLeastSpecificType(inputType, left, right);
info = PatternInfo(inputType, narrowedType);
}
else
{
var leastSpecificType = FindLeastSpecificType(info.InputType, left, right);
RequiresCompatiblePatternTypes(leastSpecificType, info.NarrowedType);
}
RequiresCompatiblePatternTypes(info.InputType, ref left);
RequiresCompatiblePatternTypes(info.InputType, ref right);
return(new BinaryCSharpPattern(info, CSharpPatternType.Or, left, right));
}
internal SliceCSharpPattern(CSharpPatternInfo info, LambdaExpression indexerAccess, CSharpPattern pattern)
: base(info)
{
IndexerAccess = indexerAccess;
Pattern = pattern;
}
internal CSharpObjectPatternInfo(CSharpPatternInfo info, ParameterExpression variable)
{
Info = info;
Variable = variable;
}
/// <summary> /// Creates a property pattern that matches on properties. /// </summary> /// <param name="info">Type information about the pattern.</param> /// <param name="type">The type to check for.</param> /// <param name="variable">The variable to assign to.</param> /// <param name="properties">The property subpatterns to apply.</param> /// <returns>A <see cref="RecursiveCSharpPattern" /> representing a property pattern.</returns> public static RecursiveCSharpPattern Property(CSharpPatternInfo info, Type type, ParameterExpression variable, params PropertyCSharpSubpattern[] properties) => Property(info, type, variable, (IEnumerable <PropertyCSharpSubpattern>)properties);
internal NotCSharpPattern(CSharpPatternInfo info, CSharpPattern negated)
: base(info)
{
Negated = negated;
}
internal ConstantCSharpPattern(CSharpPatternInfo info, ConstantExpression value)
: base(info)
{
Value = value;
}
/// <summary> /// Creates a property pattern that matches on properties. /// </summary> /// <param name="info">Type information about the pattern.</param> /// <param name="type">The type to check for.</param> /// <param name="variable">The variable to assign to.</param> /// <param name="properties">The property subpatterns to apply.</param> /// <returns>A <see cref="RecursiveCSharpPattern" /> representing a property pattern.</returns> public static RecursiveCSharpPattern Property(CSharpPatternInfo info, Type type, ParameterExpression variable, IEnumerable <PropertyCSharpSubpattern> properties) => Recursive(ObjectPatternInfo(info, variable), type, deconstructMethod: null, deconstruction: null, properties);
internal TypeCSharpPattern(CSharpPatternInfo info, Type type)
: base(info)
{
Type = type;
}
/// <summary>
/// Creates a pattern that matches a tuple using the <see cref="ITuple"/> interface.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="getLengthMethod">The method used to obtain the tuple element count.</param>
/// <param name="getItemMethod">The method used to access a tuple element.</param>
/// <param name="deconstruction">The subpatterns to apply to the tuple elements.</param>
/// <returns>A <see cref="ITupleCSharpPattern" /> representing a tuple pattern.</returns>
public static ITupleCSharpPattern ITuple(CSharpPatternInfo info, MethodInfo getLengthMethod, MethodInfo getItemMethod, IEnumerable <PositionalCSharpSubpattern> deconstruction)
{
if (info != null)
{
RequiresCompatiblePatternTypes(info.NarrowedType, typeof(ITuple));
}
else
{
info = PatternInfo(typeof(object), typeof(ITuple));
}
if (getLengthMethod != null)
{
ValidateMethodInfo(getLengthMethod);
// NB: The check for an instance method with no args is part of the Call factory.
var checkCallGetLength = Expression.Call(Expression.Default(info.NarrowedType), getLengthMethod);
if (checkCallGetLength.Type != typeof(int))
{
throw Error.ITupleGetLengthShouldReturnInt32();
}
}
else
{
getLengthMethod = ITupleGetLength;
}
if (getItemMethod != null)
{
ValidateMethodInfo(getItemMethod);
// NB: The check for an instance method with a single integer args is part of the Call factory.
var checkCallGetItem = Expression.Call(Expression.Default(info.NarrowedType), getItemMethod, Expression.Default(typeof(int)));
if (checkCallGetItem.Type != typeof(object))
{
throw Error.ITupleGetItemShouldReturnObject();
}
}
else
{
getItemMethod = ITupleGetItem;
}
var deconstructionCollection = deconstruction.ToReadOnly();
for (int i = 0, n = deconstructionCollection.Count; i < n; i++)
{
var positionalPattern = deconstructionCollection[i];
RequiresNotNull(positionalPattern, nameof(deconstruction));
if (positionalPattern.Field != null)
{
throw Error.ITuplePositionalPatternCannotHaveField(i);
}
if (positionalPattern.Parameter != null)
{
throw Error.ITuplePositionalPatternCannotHaveParameter(i);
}
//
// CONSIDER: If the input type does not match, we could trigger ChangeType (which would do the opposite of narrowing,
// i.e. generalize to 'object').
//
if (positionalPattern.Pattern.InputType != typeof(object))
{
throw Error.ITuplePositionalPatternInvalidInputType(i, positionalPattern.Pattern.InputType);
}
}
return(new ITupleCSharpPattern(info, getLengthMethod, getItemMethod, deconstructionCollection));
}
internal CSharpPattern(CSharpPatternInfo info) => _info = info;
internal DiscardCSharpPattern(CSharpPatternInfo info)
: base(info)
{
}
/// <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);
/// <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);
internal RelationalCSharpPattern(CSharpPatternInfo info, CSharpPatternType patternType, ConstantExpression value)
: base(info)
{
PatternType = patternType;
Value = value;
}
/// <summary>
/// Creates a binary pattern with the specified left and right patterns.
/// </summary>
/// <param name="info">Type information about the pattern.</param>
/// <param name="type">The type of the pattern.</param>
/// <param name="left">The left pattern.</param>
/// <param name="right">The right pattern.</param>
/// <returns>A <see cref="NotCSharpPattern" /> representing a binary pattern.</returns>
public static BinaryCSharpPattern MakeBinary(CSharpPatternInfo info, CSharpPatternType type, CSharpPattern left, CSharpPattern right) =>
type switch
{