Fix #9

.gitignore

@@ -251,3 +251,4 @@ paket-files/
 .idea/
 *.sln.iml
 tools/
+_site/

README.md

@@ -1,5 +1,10 @@
 # Strinken
 
+**Warning:** Documentation is for version 2.0.0 and is not up to date with the current state of the repo as 
+some things are being rewritten.
+
+---
+
 [![NuGet](https://img.shields.io/nuget/v/Strinken.svg)](https://www.nuget.org/packages/Strinken/)
 [![GitHub release](https://img.shields.io/github/release/k94ll13nn3/Strinken.svg)](https://github.com/k94ll13nn3/Strinken/releases/latest)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/k94ll13nn3/Strinken/master/LICENSE)

src/Strinken/Common/Extensions.cs

@@ -0,0 +1,16 @@
+// stylecop.header
+namespace Strinken.Common
+{
+    /// <summary>
+    /// Collection of common extensions methods.
+    /// </summary>
+    internal static class Extensions
+    {
+        /// <summary>
+        /// Tests if a <see cref="char"/> is a valid token name character : a-z, A-Z, 0-9, - and _
+        /// </summary>
+        /// <param name="c">The <see cref="char"/> to test.</param>
+        /// <returns>A value indicating whether the <see cref="char"/> is a valid token name character</returns>
+        public static bool IsValidTokenNameCharacter(this char c) => !char.IsLetter(c) && c != '-' && c != '_';
+    }
+}

src/Strinken/Engine/StrinkenEngine.cs

@@ -1,6 +1,7 @@
 // stylecop.header
 using System;
 using System.Text;
+using Strinken.Common;
 using Strinken.Machine;
 
 namespace Strinken.Engine
@@ -438,7 +439,7 @@ private static State ProcessOutsideToken(Cursor cursor, StringBuilder result)
         private static void ThrowIfInvalidCharacter(Cursor cursor)
         {
             var value = (char)cursor.Value;
-            if (!char.IsLetter(value) && cursor.Value != '-' && cursor.Value != '_')
+            if (value.IsValidTokenNameCharacter())
             {
                 throw new FormatException($"Illegal '{(char)cursor.Value}' at position {cursor.Position}");
             }

src/Strinken/Parser/Parser`1.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
+using Strinken.Common;
 using Strinken.Engine;
 using Strinken.Filters;
 
@@ -132,11 +133,7 @@ public void AddFilter(IFilter filter)
                 throw new ArgumentException($"{filter.Name} was already registered in the filter list.");
             }
 
-            if (string.IsNullOrWhiteSpace(filter.Name))
-            {
-                throw new ArgumentException("A filter cannot have an empty name.");
-            }
-
+            ThrowIfInvalidName(filter.Name);
             this.filters.Add(filter.Name, filter);
         }
 
@@ -151,12 +148,28 @@ public void AddTag(ITag<T> tag)
                 throw new ArgumentException($"{tag.Name} was already registered in the tag list.");
             }
 
-            if (string.IsNullOrWhiteSpace(tag.Name))
+            ThrowIfInvalidName(tag.Name);
+            this.tags.Add(tag.Name, tag);
+        }
+
+        /// <summary>
+        /// Validates a name and throws a <see cref="ArgumentException"/> if the name is invalid.
+        /// </summary>
+        /// <param name="name">The name to validate.</param>
+        private static void ThrowIfInvalidName(string name)
+        {
+            if (string.IsNullOrWhiteSpace(name))
             {
-                throw new ArgumentException("A tag cannot have an empty name.");
+                throw new ArgumentException("A name cannot be empty.");
             }
 
-            this.tags.Add(tag.Name, tag);
+            for (int i = 0; i < name.Length; i++)
+            {
+                if (name[i].IsValidTokenNameCharacter())
+                {
+                    throw new ArgumentException($"{name[i]} is an invalid character for a name.");
+                }
+            }
         }
     }
 }

test/Strinken.Tests/ParserTests.cs

@@ -153,18 +153,37 @@ public void Constructor_TagWithEmptyName_ThrowsArgumentException()
         {
             Assert.That(
                 () => new Parser<string>().WithTag("", "", s => s),
-                Throws.ArgumentException.With.Message.EqualTo("A tag cannot have an empty name."));
+                Throws.ArgumentException.With.Message.EqualTo("A name cannot be empty."));
             Assert.That(
                 () => new Parser<string>().WithTag(new EmptyNameTag()),
-                Throws.ArgumentException.With.Message.EqualTo("A tag cannot have an empty name."));
+                Throws.ArgumentException.With.Message.EqualTo("A name cannot be empty."));
         }
 
         [Test]
         public void Constructor_FilterWithEmptyName_ThrowsArgumentException()
         {
             Assert.That(
                 () => new Parser<string>().WithTag("tag", "tag", s => s).WithFilter(new EmptyNameFilter()),
-                Throws.ArgumentException.With.Message.EqualTo("A filter cannot have an empty name."));
+                Throws.ArgumentException.With.Message.EqualTo("A name cannot be empty."));
+        }
+
+        [Test]
+        public void Constructor_TagWithInvalidName_ThrowsArgumentException()
+        {
+            Assert.That(
+                () => new Parser<string>().WithTag("st*r", "", s => s),
+                Throws.ArgumentException.With.Message.EqualTo("* is an invalid character for a name."));
+            Assert.That(
+                () => new Parser<string>().WithTag(new InvalidNameTag()),
+                Throws.ArgumentException.With.Message.EqualTo("$ is an invalid character for a name."));
+        }
+
+        [Test]
+        public void Constructor_FilterWithInvalidName_ThrowsArgumentException()
+        {
+            Assert.That(
+                () => new Parser<string>().WithTag("tag", "tag", s => s).WithFilter(new InvalidNameFilter()),
+                Throws.ArgumentException.With.Message.EqualTo("! is an invalid character for a name."));
         }
 
         [Test]

test/Strinken.Tests/TestsClasses/InvalidNameFilter.cs

@@ -0,0 +1,15 @@
+using Strinken.Parser;
+
+namespace Strinken.Tests.TestsClasses
+{
+    public class InvalidNameFilter : IFilter
+    {
+        public string Description => string.Empty;
+        public string Name => "name!";
+        public string Usage => string.Empty;
+
+        public string Resolve(string value, string[] arguments) => value;
+
+        public bool Validate(string[] arguments) => true;
+    }
+}

test/Strinken.Tests/TestsClasses/InvalidNameTag.cs

@@ -0,0 +1,12 @@
+using Strinken.Parser;
+
+namespace Strinken.Tests.TestsClasses
+{
+    public class InvalidNameTag : ITag<string>
+    {
+        public string Description => string.Empty;
+        public string Name => "dollar$";
+
+        public string Resolve(string value) => value;
+    }
+}