AbstractReturns a document source position belonging to some SourceReader. It is intended to be used only by SourceReader.
PRECONDITIONS: (not verified during execution)
The SourceReader of the input this position belongs to.
The line number of this position in the current input.
It will be modified only by the constructor.
INVARIANT: line >=1, and it is a valid line in that reader.
The column number of this position in the current input.
It will be modified only by the constructor.
INVARIANT: column >= 1 and it is a valid column in that reader.
The regions the position in the current input belongs to. It will be modified only by the constructor. INVARIANT: the regions are valid in the position's reader.
The index with information about the input document
in the _sourceReader. INVARIANT: documentIndex >= 0 and it
is a valid index in that reader.
The index with information about the exact char pointed
to by this position in the input document. INVARIANT:
charIndex >= 0 and it is a valid index in that reader.
The index with information about the exact char
pointed to by this position in the visible input document.
INVARIANT: visibleCharIndex >= 0 and it is a valid index in
that reader.
The index with information about the exact char pointed
to by this position in the input document. INVARIANT:
charIndex >= 0 and it is a valid index in that reader.
The index with information about the input document
in the _sourceReader. INVARIANT: documentIndex >= 0 and it
is a valid index in that reader.
The index with information about the exact char
pointed to by this position in the visible input document.
INVARIANT: visibleCharIndex >= 0 and it is a valid index in
that reader.
The column number of this position in the current input.
It will be modified only by the constructor.
INVARIANT: column >= 1 and it is a valid column in that reader.
Answers if this position corresponds to the end of input of the SourceReader it belongs, or not. The EndOfInput is reached when all documents in the source input has been processed.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
Answers if this position correspond to one in some SourceReader, or if it is unknown.
The line number of this position in the current input.
It will be modified only by the constructor.
INVARIANT: line >=1, and it is a valid line in that reader.
The regions the position in the current input belongs to. It will be modified only by the constructor. INVARIANT: the regions are valid in the position's reader.
The SourceReader of the input this position belongs to.
The name of the input document this position belongs to.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the position is at the end of input.
The contents of the input document this position belongs to (both visible and non visible).
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
Answers if this position corresponds to the end of a document in the SourceReader it belongs, or not. The EndOfDocument is reached when all the characters in a document in the source input has been processed, but before the processing of the next document started.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the position is at the end of input.
The contents of the visible input document this position belongs to.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
Returns the full context of the source document after the position, up to the beginning of the given number of lines or the end of the document, whichever comes first.
The char at the given position is the first one in the solution.
It implements the specific logic of each subclass for the Template Method Pattern of documentContextBefore. It must be reimplemented by subclasses.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the at the end of input.
Returns the full context of the source document before the position, up to the beginning of the given number of lines, or the beginning of the document, whichever comes first.
The char at the given position is NOT included in the solution.
It implements the specific logic of each subclass for the Template Method Pattern of documentContextBefore. It must be reimplemented by subclasses.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the at the end of input.
The exact portion of the source that is enclosed between from position
and this position (not included), both visible and non-visible.
If from comes after this, the result is the empty string.
It implements the specific logic of each subclass for the Template Method Pattern of fullContentsFrom. It must be reimplemented by subclasses.
PRECONDITION:
An AbstractKnownSourcePosition related with the same SourceReader that the receiver. It indicates the starting position to consult, where the receiver is the last (not included).
The exact portion of the source that is enclosed between this position
and to position (not included), both visible and non-visible.
If this comes after to, the result is the empty string.
It implements the specific logic of each subclass for the Template Method Pattern of fullContentsTo. It must be reimplemented by subclasses.
PRECONDITION: both positions correspond to the same reader (not validated, as it is a protected operation).
A AbstractKnownSourcePosition related with the same SourceReader that the receiver. It indicates a final position to consult (not included), where the receiver is the first.
The index in the SourceReader's document indicated by the document index where the character which this positions corresponds to is stored. It may be one longer thant the lenght, in case the position is EOD.
The index in the SourceReader's document list where the document which this position corresponds is stored. It may be one longer that the lenght, in case the position is EOI.
Validates that:
Implements a common validation for the Template Method Pattern.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver or the argument positions are unknown.
SourceReader/Errors.MismatchedInputsError if the receiver and the argument positions do not belong to the same reader.
The exact portion of the source that is enclosed between from position
and this position (not included) and is visible.
If from comes after this, the result is the empty string.
It implements the specific logic of each subclass for the Template Method Pattern of visibleContentsFrom. It must be reimplemented by subclasses.
PRECONDITION: both positions correspond to the same reader (not validated, as it is a protected operation).
A AbstractKnownSourcePosition related with the same SourceReader.SourceReader that the receiver. It indicates the starting position to consult, where the receiver is the last (not included).
The exact portion of the source that is enclosed between this position
and to position (not included) and is visible.
If this comes after to, the result is the empty string.
It implements the specific logic of each subclass for the Template Method Pattern of visibleContentsTo. It must be reimplemented by subclasses.
PRECONDITION: both positions correspond to the same reader (not validated, as it is a protected operation).
A AbstractKnownSourcePosition related with the same SourceReader that the receiver. It indicates the final position to consult (not included), where the receiver is the first.
Returns the full context of the source document after the position, up to the beginning of the given number of lines or the end of the document.
The char at the given position is the first one in the solution.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the position is at the end of input.
Returns the full context of the source document before the position, up to the beginning of the given number of lines, or the beginning of the document, whichever comes first.
The char at the given position is NOT included in the solution.
PRECONDITIONS:
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the position is unknown.
SourceReader/Errors.InvalidOperationAtEOIError if the position is at the end of input.
The exact portion of the source that is enclosed between the argument position and the receiver position (not included), both visible and non visible. If the receiver does not come after the argument, the result is the empty string.
PRECONDITIONS:
A SourcePosition related with the same SourceReader that the receiver. It indicates a starting position to consult, where the receiver is the last.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver or the argument positions are unknown.
SourceReader/Errors.MismatchedInputsError if the receiver and the argument positions do not belong to the same reader.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
The exact portion of the source, both visible and non visible, that is enclosed between the receiver position and the argument position (not included). If the argument does not come after the receiver, the result is the empty string.
PRECONDITIONS:
A SourcePosition related with the same SourceReader that the receiver. It indicates a final position to consult, where the receiver is the first.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver or the argument positions are unknown.
SourceReader/Errors.MismatchedInputsError if the receiver and the argument positions do not belong to the same reader.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
The exact portion of the source that is enclosed between the from
position and this position (not included) and is visible. If this
does not come after from, the result is the empty string.
PRECONDITIONS:
A SourcePosition related with the same SourceReader that the receiver. It indicates a starting position to consult, where the receiver is the last.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver or the argument positions are unknown.
SourceReader/Errors.MismatchedInputsError if the receiver and the argument positions do not belong to the same reader.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
The exact portion of the source that is enclosed between the this
position and to position (not included) and is visible. If to does
not come after this, the result is the empty string.
PRECONDITIONS:
A SourcePosition related with the same SourceReader that the receiver. It indicates a final position to consult, where the receiver is the first.
SourceReader/Errors.InvalidOperationAtUnknownPositionError if the receiver or the argument positions are unknown.
SourceReader/Errors.MismatchedInputsError if the receiver and the argument positions do not belong to the same reader.
SourceReader/Errors.InvalidOperationAtEOIError if the receiver is the end of input.
An AbstractDocumentSourcePosition points to a particular position, that is well known, and belongs to a particular document. That implies that this position is different than EndOfInput.
There are two known cases for a position in a document. The first case is is when the source position is pointing to any character in the document, defined by the subclass DocumentSourcePosition. The second case is when the position is the last element of the document, that is, the EndOfDocument, which is a special case of position, just after the last character of the document has been reached, which is implemented by the class EndOfDocumentSourcePosition. Additionally the property isEndOfDocument may be used to check which case we are in, which is redefined in each subclass properly.
There are additional operation that the instances of this subclass can answer, such as inquiring for the document name, and the contents of the document.
Private Remarks
Among the different operations provided in this class there are a few operations used to determine context of the source input surrounding the current position: documentContextBefore, and documentContextAfter. The implementation of all these is achieved by a Template Method Pattern to provide a common validation and different logics depending on the actual subclass. Protected methods /SourcePositions.AbstractKnownSourcePosition._documentContextBefore | _documentContextBefore , and /SourcePositions.AbstractKnownSourcePosition._documentContextAfter | _documentContextAfter , are used to implement the aforementioned pattern.