Object that encapsulates Location information used for reporting
parsing (or potentially generation) errors, as well as current location
within input streams.
Shared immutable "N/A location" that can be returned to indicate
that no location information is available
Displayable description for input source: file path, URL.
transient since 2.2 so that Location itself is Serializable.
this(srcRef, -1L, totalChars, lineNr, colNr);
int lineNr, int columnNr)
if (other == this) return true;
if (other == null) return false;
if (otherLoc._sourceRef != null) return false;
return (_lineNr == otherLoc._lineNr)