public override async IAsyncEnumerable <Path> ComputeSelect(EvaluationContext ctx) { if (ListCandidate != null && Template != null) { // Expression select var select = ListCandidate.ComputeSelect(ctx); await foreach (var atom in select) { yield return(atom); } // Expression paths var paths = ListCandidate.ComputePaths(ctx); await foreach (var path in paths) { yield return(path.Append("Id")); } // Inner template select var scopedCtx = ctx.Clone(); scopedCtx.SetLocalVariable(IteratorVariableName, new EvaluationVariable( eval: TemplateUtil.VariableThatThrows(IteratorVariableName), selectResolver: () => select, pathsResolver: () => paths )); await foreach (var atom in Template.ComputeSelect(scopedCtx)) { yield return(atom); } } }
public override async Task <object> Evaluate(EvaluationContext ctx) { var listCandidate = await ListCandidate.Evaluate(ctx); if (listCandidate == null) { // Template indexer implements null propagation out of the box return(null); } if (listCandidate is IList list) { if (Index < 0 || Index >= list.Count) { // Template indexer implements null propagation out of the box return(null); } return(list[Index]); } else { throw new TemplateException($"Indexer '#{Index}' is only valid on model entity lists."); } }
public override IAsyncEnumerable <Path> ComputePaths(EvaluationContext ctx) { //var result = new List<Path>(); //await foreach (var x in ListCandidate.ComputePaths(ctx)) //{ // result.Add(x); //} //foreach (var x in result) //{ // yield return x; //} return(ListCandidate.ComputePaths(ctx)); }
public override async Task GenerateOutput(StringBuilder builder, EvaluationContext ctx, Func <string, string> encodeFunc = null) { if (ListCandidate != null && Template != null) { var listObj = (await ListCandidate.Evaluate(ctx)) ?? new List <object>(); if (listObj is IList list) { int index = 0; foreach (var listItem in list) { // Initialize new evaluation context with the new variable in it var scopedCtx = ctx.Clone(); scopedCtx.SetLocalVariable(IteratorVariableName, new EvaluationVariable( evalAsync: () => Task.FromResult(listItem), selectResolver: () => AsyncUtil.Empty <Path>(), // It doesn't matter when generating output pathsResolver: () => AsyncUtil.Empty <Path>() // It doesn't matter when generating output )); // Index, useful for setting line numbers scopedCtx.SetLocalVariable(IteratorVariableName + "_index", new EvaluationVariable( evalAsync: () => Task.FromResult <object>(index), selectResolver: () => AsyncUtil.Empty <Path>(), // It doesn't matter when generating output pathsResolver: () => AsyncUtil.Empty <Path>() // It doesn't matter when generating output )); // Run the template again on that context await Template.GenerateOutput(builder, scopedCtx, encodeFunc); index++; } } else { throw new TemplateException($"Foreach expression could not be applied. Expression ({ListCandidate}) does not evaluate to a list."); } } }
public override IAsyncEnumerable <Path> ComputeSelect(EvaluationContext ctx) { return(ListCandidate.ComputeSelect(ctx)); }