Feature: Nested formatting inside of List spacers (axuno#280)

* Added NestedFormatSpacers test. * Support nested formatting of spacers. * Removed the null handling as theres no way parameters.Count could be less than 2 as we exit out earlier in the code. * Remove redundant using statement. * Small change based on PR feedback. Use the root arguments instead of the item when formatting the spacer.
axunonb · May 12, 2022 · ea51956 · ea51956
1 parent 7a50b7e
commit ea51956
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Showing 2 changed files with 36 additions and 6 deletions.
diff --git a/src/SmartFormat.Tests/Extensions/ListFormatterTests.cs b/src/SmartFormat.Tests/Extensions/ListFormatterTests.cs
@@ -113,6 +113,16 @@ public void FormatTest(string format, string expected)
 
         }
 
+        [Test]
+        public void NestedFormatSpacers()
+        {
+            var smart = Smart.CreateDefaultSmartFormat();
+            var names = new[] { "John", "Mary", "Amy" };
+
+            Assert.AreEqual("John, Mary and Amy", smart.Format("{0:list:{}|{1} | {2} }", names, ",", "and"));
+            Assert.AreEqual("John, Mary nor Amy", smart.Format("{Names:list:{}|, | {Not:nor|or} }", new { Names = names, Not = true }));
+        }
+
         [TestCase("{0:list:{}-|}", "A-B-C-D-E-")]
         [TestCase("{0:list:{}|-}", "A-B-C-D-E")]
         [TestCase("{0:list:{}|-|+}", "A-B-C-D+E")]

diff --git a/src/SmartFormat/Extensions/ListFormatter.cs b/src/SmartFormat/Extensions/ListFormatter.cs
@@ -189,9 +189,9 @@ public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
             // itemFormat|spacer|lastSpacer
             // itemFormat|spacer|lastSpacer|twoSpacer
             var itemFormat = parameters[0];
-            var spacer = parameters.Count >= 2 ? parameters[1].GetLiteralText() : string.Empty;
-            var lastSpacer = parameters.Count >= 3 ? parameters[2].GetLiteralText() : spacer;
-            var twoSpacer = parameters.Count >= 4 ? parameters[3].GetLiteralText() : lastSpacer;
+            var spacer = parameters[1];
+            var lastSpacer = parameters.Count >= 3 ? parameters[2] : spacer;
+            var twoSpacer = parameters.Count >= 4 ? parameters[3] : lastSpacer;
 
             if (!itemFormat.HasNested)
             {
@@ -230,6 +230,18 @@ public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
                 .Initialize(null, formattingInfo.FormatDetails, format, null);
             spacerFormattingInfo.Alignment = 0;
 
+            // Note:
+            // Give spacers the data context of the root parent.
+            // formattingInfo.CurrentValue from the argument to
+            // TryEvaluateFormat(IFormattingInfo formattingInfo) only contains the list elements.
+            var rootParent = (formattingInfo as Core.Formatting.FormattingInfo);
+            do
+            {
+                rootParent = rootParent?.Parent;
+            } while (rootParent?.Parent != null);
+
+            var rootParentValue = rootParent?.CurrentValue;
+
             foreach (var item in items)
             {
                 CollectionIndex += 1; // Keep track of the index
@@ -241,15 +253,15 @@ public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
                 }
                 else if (CollectionIndex < items.Count - 1)
                 {
-                    spacerFormattingInfo.Write(spacer);
+                    WriteSpacer(spacerFormattingInfo, spacer, rootParentValue);
                 }
                 else if (CollectionIndex == 1)
                 {
-                    spacerFormattingInfo.Write(twoSpacer);
+                    WriteSpacer(spacerFormattingInfo, twoSpacer, rootParentValue);
                 }
                 else
                 {
-                    spacerFormattingInfo.Write(lastSpacer);
+                    WriteSpacer(spacerFormattingInfo, lastSpacer, rootParentValue);
                 }
 
                 // Output the nested format for this item:
@@ -268,6 +280,14 @@ public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
             return true;
         }
 
+        private static void WriteSpacer(IFormattingInfo formattingInfo, Format spacer, object? value)
+        {
+            if (spacer.HasNested)
+                formattingInfo.FormatAsChild(spacer, value);
+            else
+                formattingInfo.Write(spacer.GetLiteralText());
+        }
+
         /// <summary>
         /// Checks if any of the <see cref="Placeholder"/>'s <see cref="Placeholder.Selectors"/> has nullable <c>?</c> as their first operator.
         /// </summary>