private IToken TryGetVariable()
{
// Consume first Character which must be a ?/$
ConsumeCharacter();
// Consume other valid Characters
char next = Peek();
while (Char.IsLetterOrDigit(next) || UnicodeSpecsHelper.IsLetterOrDigit(next) || next == '-' || next == '_' || next == '\\')
{
if (next == '\\')
{
// Check its a valid Escape
HandleEscapes(TokeniserEscapeMode.QName);
}
else
{
ConsumeCharacter();
}
next = Peek();
}
// Validate
String value = Value;
if (value.EndsWith("."))
{
Backtrack();
value = value.Substring(0, value.Length - 1);
}
if (SparqlSpecsHelper.IsValidVarName(value))
{
return(new VariableToken(value, CurrentLine, StartPosition, EndPosition));
}
else
{
throw Error("The value '" + value + "' is not valid a Variable Name");
}
}
/// <summary>
/// Get column name by using qname compression and replacing special chars with underscores
/// </summary>
/// <param name="node">Node</param>
/// <param name="namespaces">Namespaces</param>
/// <returns></returns>
private string GetColumnName(INode node, INamespaceMapper namespaces)
{
if (node.NodeType != NodeType.Uri)
{
return(null);
}
Uri u = ((IUriNode)node).Uri;
String qname;
if (!namespaces.ReduceToQName(u.AbsoluteUri, out qname))
{
// Issue temporary namespaces
String tempNsPrefix = "ns" + this._nextTempID;
String nsUri = u.AbsoluteUri;
if (nsUri.Contains("#"))
{
//Create a Hash Namespace Uri
nsUri = nsUri.Substring(0, nsUri.LastIndexOf("#") + 1);
}
else if (nsUri.Contains("/"))
{
//Create a Slash Namespace Uri
nsUri = nsUri.Substring(0, nsUri.LastIndexOf("/") + 1);
}
Uri tempNsUri;
if (!Uri.TryCreate(nsUri, UriKind.Absolute, out tempNsUri))
{
tempNsUri = u;
}
while (namespaces.HasNamespace(tempNsPrefix))
{
this._nextTempID++;
tempNsPrefix = "ns" + this._nextTempID;
}
namespaces.AddNamespace(tempNsPrefix, tempNsUri);
if (!namespaces.ReduceToQName(u.AbsoluteUri, out qname))
{
qname = null;
}
}
if (qname == null)
{
// Issue temporary column name
return("entityPredicateColumn" + (++this._nextTempColumnID));
}
// Sanitize qname column name
qname = qname.StartsWith("_") ? qname.Substring(1) : qname.Replace(':', '_');
if (SparqlSpecsHelper.IsValidVarName(qname))
{
return(qname);
}
if (qname.Length == 0)
{
// Issue temporary column name
return("entityPredicateColumn " + (++this._nextTempColumnID));
}
// Clean up illegal characters
// First Character must be from PN_CHARS_U or a digit
// Add a leading p for invalid first characters
char[] cs = qname.ToCharArray();
char first = cs[0];
if (!Char.IsDigit(first) || !SparqlSpecsHelper.IsPNCharsU(first))
{
qname = "p" + qname;
if (SparqlSpecsHelper.IsValidVarName(qname))
{
return(qname);
}
cs = qname.ToCharArray();
}
for (int i = 1; i < cs.Length; i++)
{
if (i >= cs.Length - 1)
{
continue;
}
// Subsequent Chars must be from PN_CHARS (except -) or a '.'
// Replace invalid characters with _
if (cs[i] == '.' || cs[i] == '-')
{
cs[i] = '_';
}
else if (!SparqlSpecsHelper.IsPNChars(cs[i]))
{
cs[i] = '_';
}
}
// Trim trailing underscores
return(new string(cs).TrimEnd('_'));
}
