public static IEnumerable <SearchItem> Apply(SearchExpressionContext c)
{
if (c.args.Length == 0)
{
c.ThrowError("Invalid Arguments");
}
var resultStreamExpr = c.args[0];
if (!resultStreamExpr.types.IsIterable())
{
c.ThrowError($"No iterators", resultStreamExpr.outerText);
}
var exprs = new List <SearchExpression>(c.expression.parameters.Length);
for (var i = 1; i < c.expression.parameters.Length; ++i)
{
var templateExpr = c.expression.parameters[i];
var currentStreamName = $"apply@stream#{i}";
var currentStream = SearchExpression.CreateStreamExpression(resultStreamExpr, currentStreamName);
var args = new[] { currentStream }.Concat(templateExpr.parameters).ToArray();
var innerText = templateExpr.innerText;
var evaluator = templateExpr.evaluator;
if (templateExpr.types.HasFlag(SearchExpressionType.Function))
{
// Back patch arguments
var restOfArguments = templateExpr.innerText.Substring(templateExpr.evaluator.name.Length + 1);
innerText = $"{templateExpr.evaluator.name}{{{currentStreamName}, {restOfArguments}}}".GetStringView();
}
else if (templateExpr.types.HasFlag(SearchExpressionType.Text))
{
// String literal used as an evaluator name:
var filterFunction = EvaluatorManager.GetEvaluatorByNameDuringEvaluation(templateExpr.innerText.ToString(), templateExpr.innerText, c);
innerText = $"{templateExpr.innerText}{{{currentStreamName}}}".GetStringView();
evaluator = filterFunction;
}
else
{
c.ThrowError($"Bad argument type", templateExpr.outerText);
}
var patchedExpr = new SearchExpression(templateExpr.types, templateExpr.outerText, innerText, evaluator, args);
exprs.Add(patchedExpr);
resultStreamExpr = patchedExpr;
}
// Pull on the last element to start the evaluation chain
return(exprs.Last().Execute(c));
}