public static RateRule CreateFromExpression(string expression, CurrencyPair currencyPair)
{
var ex = RateRules.CreateExpression(expression);
RateRules.TryParse("", out var rules);
return(new RateRule(rules, currencyPair, ex));
}
public override SyntaxNode VisitInvocationExpression(InvocationExpressionSyntax node)
{
var exchangeName = node.Expression.ToString();
if (exchangeName.StartsWith("ERR_", StringComparison.OrdinalIgnoreCase))
{
Errors.Add(RateRulesErrors.PreprocessError);
return(base.VisitInvocationExpression(node));
}
var currencyPair = node.ArgumentList.ChildNodes().FirstOrDefault()?.ToString();
if (currencyPair == null || !CurrencyPair.TryParse(currencyPair, out var pair))
{
Errors.Add(RateRulesErrors.InvalidCurrencyIdentifier);
return(RateRules.CreateExpression($"ERR_INVALID_CURRENCY_PAIR({node.ToString()})"));
}
else
{
var rate = Rates.GetRate(exchangeName, pair);
if (rate == null)
{
Errors.Add(RateRulesErrors.RateUnavailable);
return(RateRules.CreateExpression($"ERR_RATE_UNAVAILABLE({exchangeName}, {pair.ToString()})"));
}
else
{
return(RateRules.CreateExpression(rate.ToString()));
}
}
}
public override SyntaxNode VisitInvocationExpression(InvocationExpressionSyntax node)
{
if (IsInvocation)
{
Errors.Add(RateRulesErrors.InvalidCurrencyIdentifier);
return(RateRules.CreateExpression($"ERR_INVALID_CURRENCY_PAIR({node.ToString()})"));
}
IsInvocation = true;
_ExchangeName = node.Expression.ToString();
var result = base.VisitInvocationExpression(node);
IsInvocation = false;
return(result);
}
public override SyntaxNode VisitIdentifierName(IdentifierNameSyntax node)
{
if (
(!IsInvocation || IsArgumentList) &&
CurrencyPair.TryParse(node.Identifier.ValueText, out var currentPair))
{
var replacedPair = new CurrencyPair(left: currentPair.Left == "X" ? pair.Left : currentPair.Left,
right: currentPair.Right == "X" ? pair.Right : currentPair.Right);
if (IsInvocation) // eg. replace bittrex(BTC_X) to bittrex(BTC_USD)
{
ExchangeRates.Add(new ExchangeRate()
{
CurrencyPair = replacedPair, Exchange = _ExchangeName
});
return(SyntaxFactory.IdentifierName(replacedPair.ToString()));
}
else // eg. replace BTC_X to BTC_USD, then replace by the expression for BTC_USD
{
var bestCandidate = parent.FindBestCandidate(replacedPair);
if (nested > MaxNestedCount)
{
Errors.Add(RateRulesErrors.TooMuchNestedCalls);
return(RateRules.CreateExpression($"ERR_TOO_MUCH_NESTED_CALLS({replacedPair})"));
}
var innerFlatten = CreateNewContext(replacedPair);
var replaced = innerFlatten.Visit(bestCandidate);
if (replaced is ExpressionSyntax expression)
{
var hasBinaryOps = new HasBinaryOperations();
hasBinaryOps.Visit(expression);
if (hasBinaryOps.Result)
{
replaced = SyntaxFactory.ParenthesizedExpression(expression);
}
}
if (Errors.Contains(RateRulesErrors.TooMuchNestedCalls))
{
return(RateRules.CreateExpression($"ERR_TOO_MUCH_NESTED_CALLS({replacedPair})"));
}
return(replaced);
}
}
return(base.VisitIdentifierName(node));
}
