Escaping variable names in block variable declarations

Author: SteveWilkes

ReadableExpressions.UnitTests/WhenTranslatingLanguageKeywords.cs

@@ -1,5 +1,6 @@
 namespace AgileObjects.ReadableExpressions.UnitTests
 {
+    using System;
     using System.Linq.Expressions;
     using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -56,5 +57,20 @@ private static void VerifyIsEscaped(string keyword)
 
             Assert.AreEqual("@" + keyword, translated);
         }
+
+        [TestMethod]
+        public void ShouldTranslateADeclaredBlockVariableKeyword()
+        {
+            var variable = Expression.Variable(typeof(string), "string");
+            Expression<Action> writeLine = () => Console.WriteLine("La la la");
+            var block = Expression.Block(new[] { variable }, writeLine.Body);
+            var translated = block.ToReadableString();
+
+            const string EXPECTED = @"
+string @string;
+Console.WriteLine(""La la la"");";
+
+            Assert.AreEqual(EXPECTED.TrimStart(), translated);
+        }
     }
 }

ReadableExpressions/ExpressionTranslatorRegistry.cs

@@ -11,10 +11,11 @@ internal class ExpressionTranslatorRegistry
 
         public ExpressionTranslatorRegistry()
         {
-            var negationTranslator = new NegationExpressionTranslator();
-            var memberAccessTranslator = new MemberAccessExpressionTranslator();
             var defaultTranslator = new DefaultExpressionTranslator();
             var assignmentTranslator = new AssignmentExpressionTranslator(defaultTranslator);
+            var negationTranslator = new NegationExpressionTranslator();
+            var parameterTranslator = new ParameterExpressionTranslator();
+            var memberAccessTranslator = new MemberAccessExpressionTranslator();
             var indexAccessTranslator = new IndexAccessExpressionTranslator();
             var methodCallTranslator = new MethodCallExpressionTranslator(indexAccessTranslator);
 
@@ -23,7 +24,7 @@ public ExpressionTranslatorRegistry()
                 new ArrayLengthExpressionTranslator(),
                 assignmentTranslator,
                 new BinaryExpressionTranslator(negationTranslator),
-                new BlockExpressionTranslator(),
+                new BlockExpressionTranslator(parameterTranslator),
                 new CastExpressionTranslator(),
                 new ConditionalExpressionTranslator(),
                 new ConstantExpressionTranslator(),
@@ -42,7 +43,7 @@ public ExpressionTranslatorRegistry()
                 negationTranslator,
                 new NewArrayExpressionTranslator(),
                 new NewExpressionTranslator(),
-                new ParameterExpressionTranslator(),
+                parameterTranslator,
                 new QuotedLambdaExpressionTranslator(),
                 new RuntimeVariablesExpressionTranslator(),
                 new SwitchExpressionTranslator(),

ReadableExpressions/Translators/BlockExpressionTranslator.cs

@@ -1,7 +1,6 @@
 namespace AgileObjects.ReadableExpressions.Translators
 {
     using System;
-    using System.CodeDom;
     using System.Collections.Generic;
     using System.Linq;
     using System.Linq.Expressions;
@@ -10,9 +9,12 @@ namespace AgileObjects.ReadableExpressions.Translators
 
     internal class BlockExpressionTranslator : ExpressionTranslatorBase
     {
-        public BlockExpressionTranslator()
+        private readonly ParameterExpressionTranslator _variableNameTranslator;
+
+        public BlockExpressionTranslator(ParameterExpressionTranslator variableNameTranslator)
             : base(ExpressionType.Block)
         {
+            _variableNameTranslator = variableNameTranslator;
         }
 
         public override string Translate(Expression expression, TranslationContext context)
@@ -29,15 +31,20 @@ public override string Translate(Expression expression, TranslationContext conte
             return string.Join(Environment.NewLine, blockContents);
         }
 
-        private static IEnumerable<string> GetVariableDeclarations(
+        private IEnumerable<string> GetVariableDeclarations(
             BlockExpression block,
             TranslationContext context)
         {
             return block
                 .Variables
                 .Except(context.JoinedAssignmentVariables)
                 .GroupBy(v => v.Type)
-                .Select(vGrp => $"{vGrp.Key.GetFriendlyName()} {string.Join(", ", vGrp)};");
+                .Select(vGrp => new
+                {
+                    TypeName = vGrp.Key.GetFriendlyName(),
+                    VariableNames = vGrp.Select(varName => _variableNameTranslator.Translate(varName))
+                })
+                .Select(varData => $"{varData.TypeName} {string.Join(", ", varData.VariableNames)};");
         }
 
         private static IEnumerable<string> GetBlockLines(BlockExpression block, TranslationContext context)

ReadableExpressions/Translators/ParameterExpressionTranslator.cs

@@ -41,9 +41,12 @@ internal ParameterExpressionTranslator()
 
         public override string Translate(Expression expression, TranslationContext context)
         {
-            var parameterName = ((ParameterExpression)expression).Name;
+            return Translate((ParameterExpression)expression);
+        }
 
-            return _keywords.Contains(parameterName) ? "@" + parameterName : parameterName;
+        public string Translate(ParameterExpression parameter)
+        {
+            return _keywords.Contains(parameter.Name) ? "@" + parameter.Name : parameter.Name;
         }
     }
 }