/*
* Handles "|", "&", "!" and "^" tokens
*/
private static void LogicalToken(IteratorGroup current, string token, string previousToken)
{
switch (token)
{
case "|":
// OR logical boolean algebraic operator
current.AddLogical(new Logical(Logical.LogicalType.Or));
break;
case "&":
// AND logical boolean algebraic operator
current.AddLogical(new Logical(Logical.LogicalType.And));
break;
case "!":
// NOT logical boolean algebraic operator
current.AddLogical(new Logical(Logical.LogicalType.Not));
break;
case "^":
// XOR logical boolean algebraic operator
current.AddLogical(new Logical(Logical.LogicalType.Xor));
break;
}
}
/*
* Tokenizes and initializes expression object
*/
IteratorGroup BuildExpression(
ApplicationContext context,
Node evaluatedNode,
Node exNode)
{
// Setting up a return value
var retVal = new IteratorGroup();
// Checking to see if we should run formatting logic on expression before parsing iterators
var expression = FormatExpression(context, exNode);
string previousToken = null; // Needed to keep track of previous token
var current = retVal; // Used as index iterator during tokenizing process
// Tokenizer uses StringReader to tokenize, making sure tokenizer is disposed when finished
using (var tokenizer = new Tokenizer(expression)) {
// Looping through every token in espression, building up our Iterator tree hierarchy
foreach (var idxToken in tokenizer.Tokens)
{
if (previousToken == "?")
{
// Last token, initializing type of expression and conversion type, if given
InitializeType(idxToken);
break; // finished
}
if (previousToken == null && idxToken != "/" && idxToken != "?" && idxToken != "(")
{
// Missing '/' before iterator
throw new ExpressionException(Value, "Syntax error in expression, missing iterator declaration, after evaluation expression yields; " + expression);
}
if (idxToken != "?")
{
// '?' token is handled in next iteration
current = AppendToken(context, current, idxToken, previousToken);
}
else if (previousToken == "/")
{
// Checking for '/' at end of token, before type declaration, which means we have an empty name iterator
current.AddIterator(new IteratorNamed(""));
}
// Storing previous token, since some iterators are dependent upon knowing it
previousToken = idxToken;
}
}
// Checking to see if we have open groups, which is an error
if (current.ParentGroup != null)
{
throw new ExpressionException(Value, "Group in expression was not closed. Probably missing ')' token, after evaluation expression yields; " + expression);
}
// Returning IteratorGroup to caller, but first making sure it has the right Root Group Iterator
retVal.GroupRootNode = evaluatedNode;
return(retVal);
}
/*
* Creates a modulo token
*/
private void ModuloToken(IteratorGroup current, string token)
{
// Removing "%" character
token = token.Substring(1);
// Making sure we're given a number
if (!Utilities.IsNumber(token))
{
throw new ExpressionException(
Value,
string.Format("Syntax error in modulo token '{0}', expected integer value, found string", token));
}
current.AddIterator(new IteratorModulo(int.Parse(token)));
}
/*
* Creates a valued token
*/
private void ValueToken(ApplicationContext context, IteratorGroup current, string token)
{
token = token.Substring(1); // Removing equal sign (=)
string type = null; // Defaulting to "no type", meaning "string" type basically
// Might contain a type declaration, checking here
if (token.StartsWith(":"))
{
// Yup, we've got a type declaration for our token ...
type = token.Substring(1, token.IndexOf(":", 1, StringComparison.Ordinal) - 1);
token = token.Substring(type.Length + 2);
}
current.AddIterator(new IteratorValued(token, type));
}
/*
* Creates a sibling token
*/
private void SiblingToken(IteratorGroup current, string token)
{
var intValue = token.Substring(1);
var oper = token[0];
var value = 1;
if (intValue.Length > 0 && !Utilities.IsNumber(intValue))
{
throw new ExpressionException(
Value,
string.Format("Syntax error in sibling token '{0}', expected integer value, found string", token));
}
if (intValue.Length > 0)
{
value = int.Parse(intValue);
}
current.AddIterator(new IteratorSibling(value * (oper == '+' ? 1 : -1)));
}
/*
* Creates an elder relative token
*/
private void ElderRelativeToken(IteratorGroup current, string token)
{
var name = token.Substring(1);
current.AddIterator(new IteratorNamedElderRelative(name));
}
/*
* Creates a range token [x,y]
*/
private void RangeToken(IteratorGroup current, string token)
{
// Verifying token ends with "]"
token = token.TrimEnd();
if (token [token.Length - 1] != ']')
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '{0}', no ']' at end of token", token));
}
token = token.Substring(1, token.Length - 2); // Removing [] square brackets
if (token.IndexOf(',') == -1)
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '{0}', range token must have at the very least a ',' character.", token));
}
var values = token.Split(',');
// Verifyies token has only two integer values, separated by ","
if (values.Length != 2)
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '[{0}]', ranged iterator takes two integer values, separated by ','", token));
}
var start = -1;
var end = -1;
var startStr = values [0].Trim();
var endStr = values [1].Trim();
if (startStr.Length > 0) // start index was explicitly given
{
if (!Utilities.IsNumber(startStr))
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '[{0}]', expected number, found string", token));
}
start = int.Parse(startStr, CultureInfo.InvariantCulture);
}
if (endStr.Length > 0) // end index was explicitly given
{
if (!Utilities.IsNumber(endStr))
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '[{0}]', expected number, found string", token));
}
end = int.Parse(endStr, CultureInfo.InvariantCulture);
if (end <= start)
{
throw new ExpressionException(
Value,
string.Format("Syntax error in range token '[{0}]', end must be larger than start", token));
}
}
current.AddIterator(new IteratorRange(start, end));
}
/*
* Handles an expression iterator token
*/
private IteratorGroup AppendToken(
ApplicationContext context,
IteratorGroup current,
string token,
string previousToken)
{
switch (token)
{
case "(":
// Opening new group, checking for empty name iterator first
if (previousToken == "/")
{
current.AddIterator(new IteratorNamed(""));
}
return(new IteratorGroup(current));
case ")":
// Closing group, checking for empty name iterator first and missing group opening first
if (current.ParentGroup == null) // making sure there's actually an open group first
{
throw new ExpressionException(
Value,
"Closing parenthesis ')' has no matching '(' in expression.");
}
if (previousToken == "/")
{
current.AddIterator(new IteratorNamed(""));
}
return(current.ParentGroup);
case "/":
// New token iterator
if (previousToken == "/")
{
// Two slashes "//" preceding each other, hence we're looking for a named value,
// where its name is ""
current.AddIterator(new IteratorNamed(""));
} // Else, ignoring token, since it's simply declaring the beginning (or the end) of another token
break;
case "|":
case "&":
case "^":
case "!":
// Boolean algebraic operator, opening up a new sibling-expression, checking for empty name iterator first
if (previousToken == "/")
{
current.AddIterator(new IteratorNamed(""));
}
LogicalToken(current, token, previousToken);
break;
case "..":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Root node token
current.AddIterator(new IteratorRoot());
break;
case "*":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// All children token
current.AddIterator(new IteratorChildren());
break;
case "**":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Flatten descendants token
current.AddIterator(new IteratorDescendants());
break;
case ".":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Parent node token
current.AddIterator(new IteratorParent());
break;
case "#":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Reference node token
current.AddIterator(new IteratorReference());
break;
case "<":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Left shift token
current.AddIterator(new IteratorShiftLeft());
break;
case ">":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Right shift token
current.AddIterator(new IteratorShiftRight());
break;
case "=$":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Right shift token
current.AddIterator(new IteratorDistinctValue());
break;
case "$":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Right shift token
current.AddIterator(new IteratorDistinctName());
break;
case "++":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Right shift token
current.AddIterator(new IteratorSiblingsOlder());
break;
case "--":
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Right shift token
current.AddIterator(new IteratorSiblingsYounger());
break;
default:
// Sanity check!
if (previousToken != "/")
{
throw new ExpressionException(Value, "Missing '/' before possible iterator");
}
// Handles everything else
if (token.StartsWith("="))
{
// Some type of value token, either normal value, or regex value
ValueToken(context, current, token);
}
else if (token.StartsWith("["))
{
// Range iterator token
RangeToken(current, token);
}
else if (token.StartsWith("..") && token.Length > 2)
{
// Named ancestor token
current.AddIterator(new IteratorNamedAncestor(token.Substring(2)));
}
else if (token.StartsWith("%"))
{
// Modulo token
ModuloToken(current, token);
}
else if (token.StartsWith("-") || token.StartsWith("+"))
{
// Sibling offset
SiblingToken(current, token);
}
else if (token.StartsWith("@"))
{
// Sibling offset
ElderRelativeToken(current, token);
}
else
{
if (Utilities.IsNumber(token))
{
// Numbered child token
current.AddIterator(new IteratorNumberedChild(int.Parse(token)));
}
else
{
// Defaulting to "named iterator"
current.AddIterator(new IteratorNamed(token));
}
}
break;
}
// Defaulting to returning what we came in with
return(current);
}
