org.stekikun.dolmen.syntax

Class CExtent

java.lang.Object

org.stekikun.dolmen.syntax.CExtent

Direct Known Subclasses:

Extent

public abstract class CExtent
extends Object

Instances of this class describe ranges of characters in files, and are used to link parsed entities with their concrete representation in the original sources.

These are called extents and in their general form, they can be constructed by the instantiation of parameterized extents where holes have been replaced with extents taken from other parts of the file, or from other files even. Such extents are called composite and arise during the expansion phase from a parametric grammar into a ground grammar.

Author:

Stéphane Lescuyer

See Also:

a non-composite implementation of {@link CExtent}

Constructor Summary

Constructors

Constructor and Description
CExtent()

Method Summary

Modifier and Type	Method and Description
abstract int	endPos()
abstract String	filename()
abstract String	find() The string must be of length realLength().
abstract SourceMapping.Origin	findOrigin(int offset, int length) Finding the origin in a composite extent amounts to finding the innermost extent, composite or not, whose instantiation covers the given region.
abstract int	length()
static CExtent	of(PExtent extent, List<CExtent> children, String ruleName)
abstract int	realLength() The real length of an extent is the actual length of its representation once all place-holders have been replaced.
abstract int	startCol()
abstract int	startLine()
abstract int	startPos()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CExtent

public CExtent()

Method Detail

filename

public abstract String filename()

Returns:

the absolute filename where this extent should be interpreted

startPos

public abstract int startPos()

Returns:

the starting character offset of the extent (0-based)

endPos

public abstract int endPos()

Returns:

the offset of the last character in the extent (0-based)

startLine

public abstract int startLine()

Returns:

the line where the extent starts (1-based)

startCol

public abstract int startCol()

Returns:

the column where the extent starts, i.e. the offset of the starting character from the beginning of the line (0-based)

length

public abstract int length()

Returns:

the length of this extent

realLength

public abstract int realLength()

The real length of an extent is the actual length of its representation once all place-holders have been replaced.

It can be different from length(), the length of the extent as it appeared uninstantiated in the original source.

Returns:

the real length of this extent

See Also:

find()

find

public abstract String find()

The string must be of length realLength().

Returns:

the string portion described by this extent

findOrigin

public abstract SourceMapping.Origin findOrigin(int offset,
                                                int length)

Finding the origin in a composite extent amounts to finding the innermost extent, composite or not, whose instantiation covers the given region.

Parameters:

offset - relative offset from the start of this extent

length -

Returns:

the origin of the region described by the relative offset and length

Throws:

IllegalArgumentException - if this extent does not cover the whole region described by offset and length

See Also:

SourceMapping.Origin

of

public static CExtent of(PExtent extent,
                         List<CExtent> children,
                         String ruleName)

Parameters:

extent -

children - the replacements for extent's PExtent.holes, in order

ruleName - the ground rule which produced this composite extent

Returns:

a composite extent representing the instantiation of the parameterized extent extent with the composite extents given in children