// reads a wrapped named type
// which might represent an actual named type
// or a type wrapping expression
private IStonType ReadWrappedNamedType(StonTokenReader reader)
{
if (reader.Peek().HasChartype(StonChartype.TypeOpen))
{
return(ReadWrapping(reader)); // the type is a wrapping
}
string name = null;
IList <IStonType> typeParameters = null;
bool isExtension = false;
if (reader.TryAndSkip(StonChartype.Extension))
{
isExtension = true;
}
if (reader.Peek().HasChartype(StonChartype.TextDelimiter))
{
name = reader.ReadString();
}
else if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
name = ReadCanunPath(reader);
}
else
{
throw new StonUnexpectedCharacterParsingException(reader.Position, reader.Line, reader.Column, reader.Peek(), StonChartype.TextDelimiter | StonChartype.CanunBegin);
}
if (reader.TryAndSkip(StonChartype.TypeOpen))
{
typeParameters = ReadSequence(reader, ReadWrappedUnion, StonChartype.TypeClose);
}
return(ElementFactory.CreateNamedType(name, typeParameters, isExtension));
}
/// <summary>
/// Reads a STON document from a given text reader, with whitelists of known application extensions and rules determining valid application extension names.
/// </summary>
/// <param name="reader">The text reader to read the document from.</param>
/// <param name="knownApplicationExtensionTypes">The whitelist of known application extension types.</param>
/// <param name="knownApplicationExtensionMembers">The whitelist of known application extension members.</param>
/// <param name="extensionTypesRule">The rule determining if a given name is a valid application extension type name.</param>
/// <param name="extensionMembersRule">The rule determining if a given name is a valid application extension member name.</param>
/// <returns>The read STON document.</returns>
public IStonDocument ReadDocument(
TextReader reader,
IEnumerable <string> knownApplicationExtensionTypes, IEnumerable <string> knownApplicationExtensionMembers,
Func <string, bool> extensionTypesRule, Func <string, bool> extensionMembersRule
)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
var tokenReader = new StonTokenReader(reader);
tokenReader.PeekSignificant();
var entity = _ReadEntity(tokenReader, false);
if (!tokenReader.Peek().HasChartype(StonChartype.EOS))
{
throw tokenReader.MakeUnexpectedCharacterException(StonChartype.EOS, $"Unexpected character after the valid entity: '{(char)tokenReader.Peek()}'.");
}
if (!(entity is IStonValuedEntity))
{
throw new StonException("The parsed entity is not a valid document core.");
}
return(DocumentFactory.CreateDocument(entity as IStonValuedEntity, knownApplicationExtensionTypes, knownApplicationExtensionMembers, extensionTypesRule, extensionMembersRule));
}
// reads a bare union type expression
// which might represent a single collection type expression
// or a union of multiple collection type expression
private IStonType ReadBareUnion(StonTokenReader reader, string preread, ref bool collectionStarted)
{
var permittedTypes = new List <IStonType>();
var result = ReadBareCollection(reader, preread, ref collectionStarted);
if (result == null)
{
return(null);
}
while (reader.Peek().HasChartype(StonChartype.UnionTypeSeparator))
{
if (collectionStarted)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None);
}
reader.ReadAndSkip();
permittedTypes.Add(result);
result = ReadBareCollection(reader, null, ref collectionStarted);
if (result == null)
{
throw new StonParsingException(reader.Position, reader.Line, reader.Column, "Implicit type declaration has been read as a part of union type.");
}
}
if (!permittedTypes.Any())
{
return(result);
}
else
{
permittedTypes.Add(result);
return(ElementFactory.CreateUnionType(permittedTypes));
}
}
// reads a bare collection type expression
// which might represent a bare named type expression
// or an indefinitely nested collection of element type, represented as bare named type expression
private IStonType ReadBareCollection(StonTokenReader reader, string preread, ref bool collectionStarted)
{
IStonType result = ReadBareNamedType(reader, preread);
if (result == null)
{
return(null);
}
// each collection suffix adds one more nesting of collection
while (reader.Peek().HasChartype(StonChartype.CollectionSuffixBegin))
{
if (!reader.ReadCollectionTypeSuffix(true))
{
collectionStarted = true;
break;
}
else
{
result = ElementFactory.CreateCollectionType(result);
}
}
return(result);
}
// reads a binding index
private IStonBindingIndex ReadBindingIndex(StonTokenReader reader)
{
// just a sequence of entities
reader.ExpectAndSkip(StonChartype.IndexOpen);
IEnumerable <IStonEntity> indexParameters = ReadSequence(reader, ReadEntity, StonChartype.IndexClose);
return(ElementFactory.CreateBindingIndex(indexParameters));
}
// reads a member initialization component of a complex value
private IStonMemberInit ReadMemberInit(StonTokenReader reader)
{
// just a sequence of member bindings
reader.ExpectAndSkip(StonChartype.MemberInitOpen);
IEnumerable <KeyValuePair <IStonBindingKey, IStonEntity> > memberBindings = ReadSequence(reader, ReadMemberBinding, StonChartype.MemberInitClose);
return(ElementFactory.CreateMemberInit(memberBindings));
}
// reads a type wrapping expression, in which a wrapped union type expression is contained
private IStonType ReadWrapping(StonTokenReader reader)
{
reader.ExpectAndSkip(StonChartype.TypeOpen);
var result = ReadWrappedUnion(reader);
reader.ExpectAndSkip(StonChartype.TypeClose);
return(result);
}
// reads a collection initialization component of a complex value
private IStonCollectionInit ReadCollectionInit(StonTokenReader reader, bool preStarted = false)
{
// just a sequence of entities
if (!preStarted)
{
reader.ExpectAndSkip(StonChartype.CollectionInitOpen); // the opening token might have been read earlier when reading a bare type definition
}
IEnumerable <IStonEntity> entities = ReadSequence(reader, ReadEntity, StonChartype.CollectionInitClose);
return(ElementFactory.CreateCollectionInit(entities));
}
// reads a CANUN path
private string ReadCanunPath(StonTokenReader reader)
{
StringBuilder builder = new StringBuilder();
reader.ReadCanun(builder);
while (reader.Peek().HasChartype(StonChartype.NameSeparator))
{
builder.Append((char)reader.ReadAndSkip());
reader.ReadCanun(builder);
}
return(builder.ToString());
}
// reads a wrapped collection type expression
// which might represent a wrapped named type expression
// or an indefinitely nested collection of element type, represented as wrapped named type expression
private IStonType ReadWrappedCollection(StonTokenReader reader)
{
IStonType result = ReadWrappedNamedType(reader);
// each collection suffix adds one more nesting of collection
while (reader.Peek().HasChartype(StonChartype.CollectionSuffixBegin))
{
reader.ReadCollectionTypeSuffix(false);
result = ElementFactory.CreateCollectionType(result);
}
return(result);
}
// reads a STON reference entity address
private IStonAddress ReadAddress(StonTokenReader reader)
{
IStonInitialContext initialContext = ReadInitialContext(reader);
var path = new List <IStonPathSegment>();
while (reader.Peek().HasChartype(StonChartype.PathSegmentBegin))
{
path.Add(ReadPathSegment(reader));
}
return(ElementFactory.CreateAddress(initialContext, path));
}
// reads a bare named type
// which might represent an actual named type
// a type wrapping expression
// or a declaration of implicit type
private IStonType ReadBareNamedType(StonTokenReader reader, string preread)
{
string name = null;
IList <IStonType> typeParameters = new List <IStonType>();
bool isExtension = false;
if (preread != null)
{
name = preread;
}
else
{
// reading a type wrapping or an implicit type declaration
if (reader.TryAndSkip(StonChartype.TypeOpen))
{
if (reader.TryAndSkip(StonChartype.TypeClose))
{
return(null); // implicit type declaration
}
// type wrapping
var result = ReadWrappedUnion(reader);
reader.ExpectAndSkip(StonChartype.TypeClose);
return(result);
}
if (reader.TryAndSkip(StonChartype.Extension))
{
isExtension = true;
}
if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
name = ReadCanunPath(reader);
}
else
{
throw new StonUnexpectedCharacterParsingException(reader.Position, reader.Line, reader.Column, reader.Peek(), StonChartype.CanunBegin);
}
}
if (reader.TryAndSkip(StonChartype.TypeOpen))
{
typeParameters = ReadSequence(reader, ReadWrappedUnion, StonChartype.TypeClose);
}
return(ElementFactory.CreateNamedType(name, typeParameters, isExtension));
}
/// <summary>
/// Reads a STON entity from a given text reader.
/// </summary>
/// <param name="reader">The text reader to read the entity from.</param>
/// <returns>The read STON entity.</returns>
public IStonEntity ReadEntity(TextReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
var tokenReader = new StonTokenReader(reader);
tokenReader.PeekSignificant();
var entity = _ReadEntity(tokenReader, false);
if (!tokenReader.Peek().HasChartype(StonChartype.EOS))
{
throw tokenReader.MakeUnexpectedCharacterException(StonChartype.EOS, $"Unexpected character after the valid entity: '{(char)tokenReader.Peek()}'.");
}
return(entity);
}
// reads a sequence of elements, using a given element reading function and sequence terminator chartype
private IList <TElement> ReadSequence <TElement>(StonTokenReader reader, Func <StonTokenReader, TElement> elementReading, StonChartype sequenceTerminator)
{
var result = new List <TElement>();
while (!reader.TryAndSkip(sequenceTerminator))
{
result.Add(elementReading(reader));
if (reader.TryAndSkip(StonChartype.SequenceSeparator))
{
continue;
}
else if (!reader.Peek().HasChartype(sequenceTerminator))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.SequenceSeparator | sequenceTerminator);
}
}
return(result);
}
// reads a wrapped union type expression
// which might represent a single wrapped collection type expression
// or a union of multiple wrapped collection type expression
private IStonType ReadWrappedUnion(StonTokenReader reader)
{
var permittedTypes = new List <IStonType>();
var result = ReadWrappedCollection(reader);
while (reader.TryAndSkip(StonChartype.UnionTypeSeparator))
{
permittedTypes.Add(result);
result = ReadWrappedCollection(reader);
}
if (!permittedTypes.Any())
{
return(result);
}
else
{
permittedTypes.Add(result);
return(ElementFactory.CreateUnionType(permittedTypes));
}
}
// reads a member binding in a member initialization
private KeyValuePair <IStonBindingKey, IStonEntity> ReadMemberBinding(StonTokenReader reader)
{
IStonBindingKey key;
if (reader.Peek().HasChartype(StonChartype.CanunBegin | StonChartype.TextDelimiter | StonChartype.Extension))
{
key = ReadBindingName(reader);
}
else if (reader.Peek().HasChartype(StonChartype.IndexOpen))
{
key = ReadBindingIndex(reader);
}
else
{
throw reader.MakeUnexpectedCharacterException(StonChartype.IndexOpen | StonChartype.CanunBegin | StonChartype.TextDelimiter | StonChartype.Extension);
}
reader.ExpectAndSkip(StonChartype.ValuePrompt);
IStonEntity value = ReadEntity(reader);
return(new KeyValuePair <IStonBindingKey, IStonEntity>(key, value));
}
// reads a STON address initial context
private IStonInitialContext ReadInitialContext(StonTokenReader reader)
{
int addressOpen = reader.ExpectChartype(StonChartype.AddressBegin);
// reference defining context
if (addressOpen == '$')
{
reader.PeekSignificant();
return(ElementFactory.CreateAncestorInitialContext(0));
}
else if (addressOpen == '^')
{
// document core
if (reader.Peek() == '*')
{
reader.ReadAndSkip();
return(ElementFactory.CreateGlobalEntityInitialContext(""));
}
// reference defining context ancestor
else
{
int ancestorOrder = 1;
reader.PeekSignificant();
while (reader.TryAndSkip(StonChartype.AncestorAccess))
{
++ancestorOrder;
}
return(ElementFactory.CreateAncestorInitialContext(ancestorOrder));
}
}
// globally identified entity
else
{
reader.PeekSignificant();
string globalIdentifier = reader.ReadCanun();
return(ElementFactory.CreateGlobalEntityInitialContext(globalIdentifier));
}
}
// reads a complete entity private IStonEntity ReadEntity(StonTokenReader reader) => _ReadEntity(reader, false);
// reads a construction component of a complex value
private IStonConstruction ReadConstruction(StonTokenReader reader)
{
reader.ExpectAndSkip(StonChartype.ConstructionOpen);
var positionalParameters = new List <IStonEntity>();
var namedParameters = new List <KeyValuePair <string, IStonEntity> >();
while (!reader.TryAndSkip(StonChartype.ConstructionClose))
{
// trying to read a positional parameter, or the first named parameter
if (namedParameters.Count == 0)
{
// value prompt right at the beginning clearly indicates a positional parameter
if (reader.TryAndSkip(StonChartype.ValuePrompt))
{
positionalParameters.Add(ReadEntity(reader));
}
// string literal might be an entity or a named parameter name
else if (reader.Peek().HasChartype(StonChartype.TextDelimiter))
{
var builder = new StringBuilder();
reader.ReadString(builder, false);
// if it's a single string literal followed by a value prompt, it means it is the first named parameter
if (reader.TryAndSkip(StonChartype.ValuePrompt))
{
namedParameters.Add(new KeyValuePair <string, IStonEntity>(builder.ToString(), ReadEntity(reader)));
}
// if no value prompt follows, it is assumed to be a string-valued entity
else
{
while (reader.Peek().HasChartype(StonChartype.StringChainContinue))
{
if (reader.ReadAndSkip().HasChartype(StonChartype.StringChainOpen))
{
builder.Append('\n');
}
reader.ReadString(builder, false);
}
positionalParameters.Add(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Text, builder.ToString())));
}
}
else
{
var entity = ReadEntity(reader);
if (reader.Peek().HasChartype(StonChartype.ValuePrompt))
{
// if value prompt follows after the read entity, it means the read entity must be a typeless, non-identified CANUN named value
// serving as the parameter name
if (!(entity is IStonSimpleEntity))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.SequenceSeparator | StonChartype.ConstructionClose);
}
var simpleEntity = entity as IStonSimpleEntity;
if (simpleEntity.GlobalIdentifier != null || simpleEntity.Type != null || simpleEntity.Value.DataType != StonDataType.Named || simpleEntity.Value.Content.Contains('.'))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.SequenceSeparator | StonChartype.ConstructionClose);
}
reader.ReadAndSkip();
namedParameters.Add(new KeyValuePair <string, IStonEntity>(simpleEntity.Value.Content, ReadEntity(reader)));
}
else
{
positionalParameters.Add(entity);
}
}
}
// reading remaining named parameters
else
{
string name;
if (reader.Peek().HasChartype(StonChartype.TextDelimiter))
{
name = reader.ReadString();
}
else if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
name = reader.ReadCanun();
}
else
{
throw reader.MakeUnexpectedCharacterException(StonChartype.TextDelimiter | StonChartype.CanunBegin);
}
reader.ExpectAndSkip(StonChartype.ValuePrompt);
IStonEntity value = ReadEntity(reader);
namedParameters.Add(new KeyValuePair <string, IStonEntity>(name, value));
}
if (reader.TryAndSkip(StonChartype.SequenceSeparator))
{
continue;
}
else if (!reader.Peek().HasChartype(StonChartype.ConstructionClose))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.SequenceSeparator | StonChartype.ConstructionClose);
}
}
return(ElementFactory.CreateConstruction(positionalParameters, namedParameters));
}
// reads a STON entity, complete or address
private IStonEntity _ReadEntity(StonTokenReader reader, bool isAddress)
{
// stores a CANUN identifier or path for later use until its purpose is known
string storedWord = null;
// determining the global identifier, if any
string globalIdentifier = null;
// the identifier is explicitly prepended with a global identifier sigil
if (reader.Peek().HasChartype(StonChartype.IdentifierSigil))
{
if (isAddress)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None); // identifiers are not allowed for index parameter entities
}
reader.ReadAndSkip();
globalIdentifier = reader.ReadCanun();
reader.ExpectAndSkip(StonChartype.IdentifierAssign);
}
// the entity begins with a CANUN name that might or might not be a global identifier
else if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
storedWord = reader.ReadCanun();
// if and only if the CANUN name is followed by a global identifier assignment token
// the name is to be used as a global identifier
if (reader.Peek().HasChartype(StonChartype.IdentifierAssign))
{
if (isAddress)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None); // once again, identifiers are not allowed for index parameter entities
}
reader.ReadAndSkip();
globalIdentifier = storedWord;
storedWord = null;
}
}
// finding the address, if any
if (reader.Peek().HasChartype(StonChartype.AddressBegin))
{
// the reference entity cannot have a type declaration
if (storedWord != null)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None);
}
return(ElementFactory.CreateReferenceEntity(ReadAddress(reader), globalIdentifier));
}
// determining the type, if any
IStonType type = null;
bool isTypeFromWord = false;
bool collectionStarted = false; // a variable indicating whether during reading type a collection initialization has been started or not
// when bare type definitions are involved, a collection initialization might appear like a collection type suffix
// so it's impossible to tell the two apart before reading the initial sign
// no word is stored; either there was no word in the first place, or there was a global identifier before
if (storedWord == null)
{
// storing a CANUN path, which might be a type or a named value
if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
storedWord = ReadCanunPath(reader);
}
// reading a type if the following token is characteristic for types
else if (reader.Peek().HasChartype(StonChartype.Extension | StonChartype.TypeOpen))
{
type = ReadBareUnion(reader, null, ref collectionStarted);
}
}
else
{
// if a CANUN name is stored, it might be a part of a longer CANUN path
// which itself might be a type or a named value
if (reader.Peek().HasChartype(StonChartype.NameSeparator))
{
storedWord = storedWord + (char)reader.ReadAndSkip() + ReadCanunPath(reader);
}
}
// if a CANUN path is followed by a type opening, collection suffix or a union type separator
// it means that path must be a type name
if (storedWord != null && reader.Peek().HasChartype(StonChartype.TypeOpen | StonChartype.CollectionSuffixBegin | StonChartype.UnionTypeSeparator))
{
type = ReadBareUnion(reader, storedWord, ref collectionStarted);
storedWord = null;
}
if (storedWord != null)
{
type = ElementFactory.CreateNamedType(storedWord);
isTypeFromWord = true;
}
// finding the complex value, if any
// when the collection initialization has been entered when reading a type definition
// the rest of the collection initialization is read
if (collectionStarted)
{
// a complex value is not allowed in an address index parameter
if (isAddress)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.CollectionSuffixContinue);
}
// reading the rest of the collection initialization
// and subsequent member initialization, if available
IStonCollectionInit collectionInit = ReadCollectionInit(reader, true);
IStonMemberInit memberInit = null;
if (reader.Peek().HasChartype(StonChartype.MemberInitOpen))
{
memberInit = ReadMemberInit(reader);
}
return(ElementFactory.CreateComplexEntity(null, memberInit, collectionInit, type, globalIdentifier));
}
// reading any valid combination of complex value components (construction, member initialization, collection initialization)
if (reader.Peek().HasChartype(StonChartype.ConstructionOpen | StonChartype.MemberInitOpen | StonChartype.CollectionInitOpen))
{
// a complex value is not allowed in an address index parameter
if (isAddress)
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None);
}
IStonConstruction constructor = null;
IStonMemberInit memberInit = null;
IStonCollectionInit collectionInit = null;
if (reader.Peek().HasChartype(StonChartype.ConstructionOpen))
{
constructor = ReadConstruction(reader);
}
if (reader.Peek().HasChartype(StonChartype.MemberInitOpen))
{
memberInit = ReadMemberInit(reader);
}
if (reader.Peek().HasChartype(StonChartype.CollectionInitOpen))
{
collectionInit = ReadCollectionInit(reader);
if (memberInit == null && reader.Peek().HasChartype(StonChartype.MemberInitOpen))
{
memberInit = ReadMemberInit(reader);
}
}
return(ElementFactory.CreateComplexEntity(constructor, memberInit, collectionInit, type, globalIdentifier));
}
// finding the string, binary or number simple value, if complex value is not present
// reading a string literal or string literals chain
if (reader.TryAndSkip(StonChartype.StringChainOpen))
{
if (!reader.Peek().HasChartype(StonChartype.TextDelimiter | StonChartype.CodeDelimiter))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.TextDelimiter | StonChartype.CodeDelimiter);
}
}
if (reader.Peek().HasChartype(StonChartype.TextDelimiter | StonChartype.CodeDelimiter))
{
bool isCode = reader.Peek().HasChartype(StonChartype.CodeDelimiter); // whether the value is a text or a code
var builder = new StringBuilder();
reader.ReadString(builder, isCode);
while (reader.Peek().HasChartype(StonChartype.StringChainContinue))
{
if (reader.ReadAndSkip().HasChartype(StonChartype.StringChainOpen))
{
builder.Append('\n');
}
reader.ReadString(builder, isCode);
}
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(isCode ? StonDataType.Code : StonDataType.Text, builder.ToString()), type, globalIdentifier));
}
// reading a number of binary value
bool minus = false;
// reading the initial sign, if any
if (reader.Peek().HasChartype(StonChartype.Sign))
{
if (reader.ReadAndSkip() == '-')
{
minus = true;
}
// a digit must follow the sign
if (!reader.Peek().HasChartype(StonChartype.Digit))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.Digit);
}
}
// both number and binary literals might begin with a zero (excluding initial sign)
// whichever it is, is decided by whether the zero is followed by a base identifier or not
if (reader.TryAndSkip(StonChartype.ZeroDigit))
{
if (reader.Peek().HasChartype(StonChartype.BaseIdentifier))
{
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Binary, reader.ReadBinaryContent(minus)), type, globalIdentifier));
}
else
{
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Number, reader.ReadNumberContent(minus)), type, globalIdentifier));
}
}
// only number literals might begin with a non-zero digit (aside from initial sign)
else if (reader.Peek().HasChartype(StonChartype.NonZeroDigit))
{
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Number, reader.ReadNumberContent(minus)), type, globalIdentifier));
}
// finding the named or null value, if everything else fails
string value;
if (reader.Peek().HasChartype(StonChartype.CanunBegin))
{
value = ReadCanunPath(reader);
}
else if (isTypeFromWord)
{
value = (type as IStonNamedType).Name;
type = null;
}
else
{
throw reader.MakeUnexpectedCharacterException(StonChartype.None); // there is no named value, and thus there's all the reason to panic
}
if (value == "null")
{
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Null, null), type, globalIdentifier));
}
else
{
return(ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Named, value), type, globalIdentifier));
}
}
// reads a STON address path segment
private IStonPathSegment ReadPathSegment(StonTokenReader reader)
{
int pathOpen = reader.ExpectAndSkip(StonChartype.PathSegmentBegin);
if (pathOpen == '.')
{
// ancestor access segment
if (reader.TryAndSkip(StonChartype.AncestorAccess))
{
int ancestorOrder = 1;
while (reader.TryAndSkip(StonChartype.AncestorAccess))
{
++ancestorOrder;
}
return(ElementFactory.CreateAncestorPathSegment(ancestorOrder));
}
// named member access segment
else
{
return(ElementFactory.CreateMemberPathSegment(ReadBindingName(reader)));
}
}
else
{
// collection element access segment
if (reader.TryAndSkip(StonChartype.PathSegmentCollection))
{
int currentPosition = reader.Position;
int currentLine = reader.Line;
int currentColumn = reader.Column;
if (reader.Peek().HasChartype(StonChartype.Sign))
{
if (reader.Peek() == '-')
{
throw new StonParsingException(currentPosition, currentLine, currentColumn, "Collection element index cannot be negative.");
}
reader.ReadAndSkip();
if (!reader.Peek().HasChartype(StonChartype.Digit))
{
throw reader.MakeUnexpectedCharacterException(StonChartype.Digit);
}
}
IStonEntity elementIndex;
// number or binary integer index
if (reader.Peek().HasChartype(StonChartype.ZeroDigit))
{
reader.ReadAndSkip();
if (reader.Peek().HasChartype(StonChartype.BaseIdentifier))
{
elementIndex = ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Binary, reader.ReadBinaryContent(false)));
}
else
{
elementIndex = ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Number, reader.ReadNumberContent(false)));
}
}
// number integer index
else if (reader.Peek().HasChartype(StonChartype.NonZeroDigit))
{
elementIndex = ElementFactory.CreateSimpleEntity(ElementFactory.CreateSimpleValue(StonDataType.Number, reader.ReadNumberContent(false)));
}
// resolved reference index
else if (reader.Peek().HasChartype(StonChartype.AddressBegin))
{
elementIndex = ElementFactory.CreateReferenceEntity(ReadAddress(reader));
}
else
{
throw reader.MakeUnexpectedCharacterException(StonChartype.Digit | StonChartype.AddressBegin | StonChartype.Sign);
}
reader.ExpectAndSkip(StonChartype.IndexClose);
return(ElementFactory.CreateCollectionElementPathSegment(elementIndex));
}
// index member access segment
else
{
IEnumerable <IStonEntity> indexParameters = ReadSequence(reader, ReadAddressEntity, StonChartype.IndexClose);
return(ElementFactory.CreateMemberPathSegment(ElementFactory.CreateBindingIndex(indexParameters)));
}
}
}
// reads an address index parameter entity; i.e. simple or reference, without the global identifier private IStonEntity ReadAddressEntity(StonTokenReader reader) => _ReadEntity(reader, true);