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 == '_')
{
ConsumeCharacter();
next = Peek();
}
// Validate
String value = Value;
if (IsValidVarName(value))
{
return(new VariableToken(value, CurrentLine, StartPosition, EndPosition));
}
else
{
throw Error("The value '" + value + "' is not valid a Variable Name");
}
}
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");
}
}
private bool IsValidVarName(String value)
{
if (_isValidVarName.IsMatch(value))
{
return(true);
}
else
{
// Have to validate Character by Character
char[] cs = value.ToCharArray();
char first = cs[0];
// First character must be an underscore or letter
if (first == '_' || Char.IsLetter(first) || UnicodeSpecsHelper.IsLetter(first))
{
// Remaining Characters must be underscores, letters, numbers or hyphens
for (int i = 1; i < cs.Length; i++)
{
char c = cs[i];
if (c == '_' || c == '-' || Char.IsLetterOrDigit(c) || UnicodeSpecsHelper.IsLetterOrDigit(c))
{
// OK
}
else
{
// Invalid Character
return(false);
}
}
// If we get here it's all fine
return(true);
}
else
{
// Invalid Start Character
return(false);
}
}
}