private ExpressionNode parseExpression() {
ExpressionNode result = null;
var restorePoint = this.createRestorePoint();
switch (lexicalUnit) {
case Identifier:
case VerbatimIdentifier:
case OpenParenthesis:
result = parseLambdaExpression();
break;
case ContextualKeyword:
if (scanner.Keyword == Keyword.From) {
result = parseQueryExpression();
} else {
result = parseLambdaExpression();
}
break;
}
if (result != null) {
return result;
} else {
this.restore(restorePoint);
}
result = parseConditionalExpression();
switch (result.ExpressionKind) {
case Conditional:
case Binary:
return result;
}
AssignOperator op = null;
switch (lexicalUnit) {
case Assign:
nextLexicalUnit(true);
op = AssignOperator.Assign;
break;
case AddAssign:
nextLexicalUnit(true);
op = AssignOperator.Add;
break;
case AndAssign:
nextLexicalUnit(true);
op = AssignOperator.And;
break;
case DivideAssign:
nextLexicalUnit(true);
op = AssignOperator.Divide;
break;
case LeftShiftAssign:
nextLexicalUnit(true);
op = AssignOperator.LeftShift;
break;
case ModuloAssign:
nextLexicalUnit(true);
op = AssignOperator.Modulo;
break;
case MultiplyAssign:
nextLexicalUnit(true);
op = AssignOperator.Multiply;
break;
case OrAssign:
nextLexicalUnit(true);
op = AssignOperator.Or;
break;
case SubtractAssign:
nextLexicalUnit(true);
op = AssignOperator.Subtract;
break;
case XorAssign:
nextLexicalUnit(true);
op = AssignOperator.Xor;
break;
case GreaterThan:
switch (scanner.nextLexicalUnit()) {
case GreaterThanOrEqual:
nextLexicalUnit(true);
op = AssignOperator.RightShift;
break;
case GreaterThan:
if (scanner.nextLexicalUnit() != LexicalUnit.GreaterThanOrEqual) {
throw error(ParseErrorId.UnexpectedLexicalUnit);
}
nextLexicalUnit(true);
op = AssignOperator.UnsignedRightShift;
break;
default:
throw error(ParseErrorId.UnexpectedLexicalUnit);
}
break;
}
if (op != null) {
var assign = new AssignExpressionNode();
copyScannerState(result, assign);
assign.Left = result;
assign.Operator = op;
assign.Right = parseExpression();
assign.EndPosition = assign.Right.EndPosition;
result = assign;
}
return result;
}
protected virtual TResult handleAssign(AssignExpressionNode assign, TSource source, bool nested)
{
return(defaultHandler());
}