Create extensions to selection/contexts/tokens for ease of validating the question of whether a selection contains a given context or token, plus associated tests.

Author: bclothier

Rubberduck.Parsing/Rubberduck.Parsing.csproj

@@ -199,6 +199,7 @@
     <Compile Include="ComReflection\ComProject.cs" />
     <Compile Include="Rewriter\IModuleRewriter.cs" />
     <Compile Include="PreProcessing\VBAPreprocessorVisitor.cs" />
+    <Compile Include="SelectionExtensions.cs" />
     <Compile Include="SymbolList.cs" />
     <Compile Include="Symbols\AliasDeclaration.cs" />
     <Compile Include="Symbols\DeclarationFinderFactory.cs" />

Rubberduck.Parsing/SelectionExtensions.cs

@@ -0,0 +1,51 @@
+using Antlr4.Runtime;
+using Rubberduck.VBEditor;
+using System;
+
+namespace Rubberduck.Parsing
+{
+    /// <summary>
+    /// Provide extensions on selections & contexts/tokens
+    /// to assist in validating whether a selection contains
+    /// a given context or a token. 
+    /// </summary>
+    public static class SelectionExtensions
+    {
+        public static bool Contains(this Selection selection, IToken token)
+        {
+            return
+                (((selection.StartLine == token.Line) && (selection.StartColumn - 1) <= token.Column) || (selection.StartLine < token.Line))
+             && (((selection.EndLine == token.Line) && (selection.EndColumn - 1) >= (token.EndColumn())) || (selection.EndLine > token.Line));
+        }
+
+        public static bool Contains(this ParserRuleContext context, Selection selection)
+        {
+            return
+               (((selection.StartLine == context.Start.Line) && (selection.StartColumn - 1) <= context.Start.Column) || (selection.StartLine < context.Start.Line))
+            && (((selection.EndLine == context.Stop.Line) && (selection.EndColumn - 1) >= (context.Stop.EndColumn())) || (selection.EndLine > context.Stop.Line));
+        }
+
+        /// <summary>
+        /// Because a token can be spread across multiple lines with line continuations
+        /// it is necessary to do some work to determine the token's actual ending column.
+        /// Whitespace and newline should be preserved within the token.
+        /// </summary>
+        /// <param name="token">The last token within a given context to test</param>
+        /// <returns></returns>
+        public static int EndColumn(this IToken token)
+        {
+            if (token.Text.Contains(Environment.NewLine))
+            {
+                var splitStrings = token.Text.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
+                var tokenOnLastLine = splitStrings[splitStrings.Length - 1];
+
+                return tokenOnLastLine.Length;
+            }
+            else
+            {
+                return token.Column + token.Text.Length;
+            }
+
+        }
+    }
+}