private static Expression ParseFactor(ExpressionLexer lexer)
{
ExprTokenType tokenType = lexer.PeekNextToken();
if (tokenType == ExprTokenType.Number)
return new PrimitiveExpression((int)lexer.GetNextToken(ExprTokenType.Number));
if (tokenType == ExprTokenType.String)
return new PrimitiveExpression((string)lexer.GetNextToken(ExprTokenType.String));
if (tokenType == ExprTokenType.Symbol)
{
string symbol = (string) lexer.GetNextToken(ExprTokenType.Symbol);
if (lexer.PeekNextToken() == ExprTokenType.Dot)
{
lexer.GetNextToken(ExprTokenType.Dot);
Expression exprInContext = ParseFactor(lexer);
return new ContextExpression(symbol, exprInContext, new Expression[0]);
}
if (lexer.PeekNextToken() == ExprTokenType.Open)
{
lexer.GetNextToken(ExprTokenType.Open);
var parameters = new List<Expression>();
while (lexer.PeekNextToken() != ExprTokenType.Close)
{
if (parameters.Count > 0)
lexer.GetNextToken(ExprTokenType.Comma);
parameters.Add(ParseCondCombo(lexer));
}
lexer.GetNextToken(ExprTokenType.Close);
if (lexer.PeekNextToken() == ExprTokenType.Dot)
{
lexer.GetNextToken(ExprTokenType.Dot);
Expression exprInContext = ParseFactor(lexer);
return new ContextExpression(symbol, exprInContext, parameters.ToArray());
}
return new FunctionExpression(symbol, parameters.ToArray());
}
return new SymbolExpression(symbol);
}
if (tokenType == ExprTokenType.Open)
{
lexer.GetNextToken(ExprTokenType.Open);
Expression result = ParseCondCombo(lexer);
lexer.GetNextToken(ExprTokenType.Close);
return result;
}
if (tokenType == ExprTokenType.Minus || tokenType == ExprTokenType.NOT)
{
lexer.GetNextToken(tokenType);
return new UnaryExpression(ParseFactor(lexer), tokenType);
}
throw new ParseException("Unexpected token " + tokenType, lexer.CurrentPosition);
}
public void PeekingShouldThrowWhenIncorrectCharacterAtStart()
{
ExpressionLexer lexer = new ExpressionLexer("#$*@#", false, false);
Action peek = () => lexer.PeekNextToken();
peek.Throws <ODataException>(ODataErrorStrings.ExpressionLexer_InvalidCharacter("#", "0", "#$*@#"));
}
public void ShouldOutputTokenWhenNoError()
{
ExpressionLexer lexer = new ExpressionLexer("null", false, false);
ExpressionToken result = lexer.PeekNextToken();
lexer.CurrentToken.Should().NotBe(result);
result.Kind.Should().Be(ExpressionTokenKind.NullLiteral);
}
public void ShouldOutputTokenWhenNoError()
{
ExpressionLexer lexer = new ExpressionLexer("null", false, false);
ExpressionToken result = lexer.PeekNextToken();
Assert.NotEqual(result, lexer.CurrentToken);
Assert.Equal(ExpressionTokenKind.NullLiteral, result.Kind);
}
private static Expression ParseTernary(ExpressionLexer lexer)
{
var expr = ParseCondCombo(lexer);
if (lexer.PeekNextToken() == ExprTokenType.QuestionMark)
{
lexer.GetNextToken(ExprTokenType.QuestionMark);
var trueValue = ParseTernary(lexer);
lexer.GetNextToken(ExprTokenType.Colon);
var falseValue = ParseTernary(lexer);
return new TernaryExpression(expr, trueValue, falseValue);
}
return expr;
}