Add else statement in unless tag (#265)

Fixes #260
sebastienros · Feb 10, 2021 · 0a007c6 · 0a007c6
1 parent b85fb7e
commit 0a007c6
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Showing 3 changed files with 53 additions and 3 deletions.
diff --git a/Fluid.Tests/UnlessStatementTests.cs b/Fluid.Tests/UnlessStatementTests.cs
@@ -34,7 +34,7 @@ public async Task UnlessDoesntProcessWhenTrue()
         }
 
         [Fact]
-        public async Task IfCanProcessWhenFalse()
+        public async Task UnlessCanProcessWhenFalse()
         {
             var e = new UnlessStatement(
                 FALSE,
@@ -46,5 +46,42 @@ public async Task IfCanProcessWhenFalse()
 
             Assert.Equal("x", sw.ToString());
         }
+
+        [Fact]
+        public async Task UnlessShouldProcessElseWhenFalse()
+        {
+            var e = new UnlessStatement(
+                FALSE,
+                new List<Statement> {
+                    new TextSpanStatement("x")
+                },
+                new ElseStatement(new List<Statement> {
+                        new TextSpanStatement("y")
+                    }));
+
+            var sw = new StringWriter();
+            await e.WriteToAsync(sw, HtmlEncoder.Default, new TemplateContext());
+
+            Assert.Equal("x", sw.ToString());
+        }
+
+        [Fact]
+        public async Task UnlessShouldProcessElseWhenTrue()
+        {
+            var e = new UnlessStatement(
+                TRUE,
+                new List<Statement> {
+                    new TextSpanStatement("x")
+                },
+                new ElseStatement(new List<Statement> {
+                        new TextSpanStatement("y")
+                    })
+                );
+
+            var sw = new StringWriter();
+            await e.WriteToAsync(sw, HtmlEncoder.Default, new TemplateContext());
+
+            Assert.Equal("y", sw.ToString());
+        }
     }
 }
diff --git a/Fluid/Ast/UnlessStatement.cs b/Fluid/Ast/UnlessStatement.cs
@@ -9,12 +9,15 @@ public class UnlessStatement : TagStatement
     {
         public UnlessStatement(
             Expression condition,
-            List<Statement> statements) : base(statements)
+            List<Statement> statements,
+            ElseStatement elseStatement = null) : base(statements)
         {
             Condition = condition;
+            Else = elseStatement;
         }
 
         public Expression Condition { get; }
+        public ElseStatement Else { get; }
 
         public override async ValueTask<Completion> WriteToAsync(TextWriter writer, TextEncoder encoder, TemplateContext context)
         {
@@ -37,6 +40,13 @@ public override async ValueTask<Completion> WriteToAsync(TextWriter writer, Text
 
                 return Completion.Normal;
             }
+            else
+            {
+                if (Else != null)
+                {
+                    await Else.WriteToAsync(writer, encoder, context);
+                }
+            }
 
             return Completion.Normal;
         }

diff --git a/Fluid/FluidParser.cs b/Fluid/FluidParser.cs
@@ -245,8 +245,11 @@ public FluidParser()
             var UnlessTag = LogicalExpression
                         .AndSkip(TagEnd)
                         .And(AnyTagsList)
+                        .And(ZeroOrOne(
+                            CreateTag("else").SkipAnd(AnyTagsList))
+                            .Then(x => x != null ? new ElseStatement(x) : null))
                         .AndSkip(CreateTag("endunless"))
-                        .Then<Statement>(x => new UnlessStatement(x.Item1, x.Item2))
+                        .Then<Statement>(x => new UnlessStatement(x.Item1, x.Item2, x.Item3))
                         .ElseError("Invalid 'unless' tag");
             var CaseTag = Primary
                        .AndSkip(TagEnd)