public static LiquidExpressionResult Eval(
LiquidExpression expression,
IEnumerable<Option<IExpressionConstant>> leaves,
ITemplateContext templateContext)
{
// calculate the first part of the expression
var objResult = expression.Expression == null ?
LiquidExpressionResult.Success(new None<IExpressionConstant>()) :
expression.Expression.Eval(templateContext, leaves);
if (objResult.IsError)
{
return objResult;
}
// Compose a chain of filters, making sure type-casting
// is done between them.
IEnumerable<Tuple<FilterSymbol, IFilterExpression>> filterExpressionTuples;
try
{
filterExpressionTuples = expression.FilterSymbols.Select(symbol =>
new Tuple<FilterSymbol, IFilterExpression>(symbol, InstantiateFilter(templateContext, symbol)))
.ToList();
}
catch (Exception ex)
{
return LiquidExpressionResult.Error(ex.Message);
}
var erroringFilternames = filterExpressionTuples.Where(x => x.Item2 == null).Select(x => x.Item1).ToList();
if (erroringFilternames.Any())
{
//throw new Exception("Missing filters...");
//return ConstantFactory.CreateError<StringValue>();
return LiquidExpressionResult.Error("Missing filters: " + String.Join(", ", erroringFilternames.Select(x => x.Name)));
}
var filterChain = FilterChain.CreateChain(
objResult.GetType(),
templateContext,
filterExpressionTuples.Select(x => x.Item2));
// apply the composed function to the object
return filterChain(objResult.SuccessResult);
}
public void StartLiquidExpression(IExpressionDescription expressionDescription)
{
//Console.WriteLine("LiquidExpressionBuilder >>> PUSH");
LiquidExpression liquidExpression = new LiquidExpression { Expression = expressionDescription };
var child = new TreeNode<LiquidExpression>(liquidExpression);
if (_liquidExpressionStack.Any())
{
//Console.WriteLine(" to " + _liquidExpressionStack.Peek());
_liquidExpressionStack.Peek().AddChild(child);
}
else
{
//Console.WriteLine(" to ROOT ");
_liquidExpressionTree = child;
}
_liquidExpressionStack.Push(child);
}
public void Visit(LiquidExpression liquidExpression)
{
_result += liquidExpression.ToString();
}
/// <summary>
/// Process the object / filter chain
/// </summary>
/// <param name="liquidExpression"></param>
public void Visit(LiquidExpression liquidExpression)
{
//Console.WriteLine("Visiting Object Expression ");
LiquidExpressionEvaluator.Eval(liquidExpression, new List<Option<IExpressionConstant>>(), _templateContext)
.WhenSuccess(x => x.WhenSome(some => AppendTextToCurrentAccumulator(Render(x.Value)))
.WhenNone(() => AppendTextToCurrentAccumulator("")))
.WhenError(RenderError);
}