Merge pull request #2842 from FirelyTeam/feature/FP-iif-context

Changed iif to work with the correct context
FirelyTeam · Sep 2, 2024 · f859b8d · f859b8d
2 parents 195a559 + ccd7c70
commit f859b8d
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Showing 2 changed files with 13 additions and 13 deletions.
diff --git a/src/Hl7.Fhir.Base/FhirPath/Expressions/SymbolTableInit.cs b/src/Hl7.Fhir.Base/FhirPath/Expressions/SymbolTableInit.cs
@@ -328,17 +328,21 @@ private static IEnumerable<ITypedElement> runIif(Closure ctx, IEnumerable<Invoke
         {
             // iif(criterion: expression, true-result: collection [, otherwise-result: collection]) : collection
             // note: short-circuit behavior is expected in this function
+            var focus = arguments.First()(ctx, InvokeeFactory.EmptyArgs);
 
-            var expression = arguments.Skip(1).First()(ctx, InvokeeFactory.EmptyArgs);
+            var newContext = ctx.Nest(focus);
+            newContext.SetThis(focus);
+
+            var expression = arguments.Skip(1).First()(newContext, InvokeeFactory.EmptyArgs);
             var trueResult = arguments.Skip(2).First();
             var otherResult = arguments.Skip(3).FirstOrDefault();
 
             if (expression.Count() > 1)
                 throw Error.InvalidOperation($"Result of {nameof(expression)} is not of type boolean");
 
             return (expression.BooleanEval() ?? false)
-                ? trueResult(ctx, InvokeeFactory.EmptyArgs)
-                : otherResult == null ? ElementNode.EmptyList : otherResult(ctx, InvokeeFactory.EmptyArgs);
+                ? trueResult(newContext, InvokeeFactory.EmptyArgs) // share focus with this function
+                : otherResult == null ? ElementNode.EmptyList : otherResult(newContext, InvokeeFactory.EmptyArgs);
         }
 
         private static IEnumerable<ITypedElement> runWhere(Closure ctx, IEnumerable<Invokee> arguments)

diff --git a/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTest.cs b/src/Hl7.FhirPath.R4.Tests/PocoTests/FhirPathEvaluatorTest.cs
@@ -22,6 +22,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
+using System.Reflection.Metadata.Ecma335;
 using System.Xml.Linq;
 
 namespace Hl7.FhirPath.R4.Tests
@@ -164,17 +165,12 @@ public void TestSubsetting()
 
 
         [TestMethod]
-        public void TestIIf()
+        public void TestIIfContext()
         {
-            fixture.IsTrue(@"Patient.name.iif(exists(), 'named', 'unnamed') = 'named'");
-            fixture.IsTrue(@"Patient.name.iif(empty(), 'unnamed', 'named') = 'named'");
-
-            fixture.IsTrue(@"Patient.contained[0].name.iif(exists(), 'named', 'unnamed') = 'named'");
-            fixture.IsTrue(@"Patient.contained[0].name.iif(empty(), 'unnamed', 'named') = 'named'");
-
-            fixture.IsTrue(@"Patient.name.iif({}, 'named', 'unnamed') = 'unnamed'");
-
-            //   fixture.IsTrue(@"Patient.name[0].family.iif(length()-8 != 0, 5/(length()-8), 'no result') = 'no result'");
+            var res = fixture.TestInput.Scalar("Patient.contained[0].name[0].given[0].iif(true, single())");
+            res.Should().BeOfType<string>().Subject.Should().Be("Eve");
+            res = fixture.TestInput.Scalar("Patient.contained[0].name.iif(use = 'official', 'given', given.join(''))"); // comparison between collection and string
+            res.Should().BeOfType<string>().Subject.Should().Be("EveEveline");
         }
 
         [TestMethod]