Lex unquoted string literals

Lexer.Tests/MLexerShould.cs

@@ -1,8 +1,7 @@
 using System.Linq;
-using Lexer;
 using NUnit.Framework;
 
-namespace Parser.Tests
+namespace Lexer.Tests
 {
     public class MLexerShould
     {
@@ -22,8 +21,9 @@ namespace Parser.Tests
                 new[] {"undefined", "is", "not", "a", "function"},
                 tokens.Take(5).Select(token => token.PureToken.LiteralText));
             CollectionAssert.AreEqual(
-                Enumerable.Repeat(TokenKind.Identifier, 5),
-                tokens.Take(5).Select(token => token.PureToken.Kind));
+                new[] { TokenKind.Identifier, TokenKind.UnquotedStringLiteral, TokenKind.UnquotedStringLiteral,
+                        TokenKind.Identifier, TokenKind.UnquotedStringLiteral },
+                tokens.Take(5).Select(token => token.Kind));
         }
         
         [Test]

Lexer.Tests/TextWindowShould.cs

@@ -1,7 +1,6 @@
-using Lexer;
 using NUnit.Framework;
 
-namespace Parser.Tests
+namespace Lexer.Tests
 {
     [TestFixture]
     public class TestWindowShould

Lexer.Tests/TextWindowWithNullShould.cs

@@ -1,7 +1,6 @@
-using Lexer;
 using NUnit.Framework;
 
-namespace Parser.Tests
+namespace Lexer.Tests
 {
     [TestFixture]
     public class TestWindowWithNullShould

Lexer/MLexer.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 
@@ -363,9 +364,55 @@ namespace Lexer
             return PureTokenFactory.CreateDoubleQuotedStringLiteral(literal);
         }
 
+        private PureToken ContinueParsingUnquotedStringLiteral()
+        {
+            var n = 0;
+            while (true)
+            {
+                var c = Window.PeekChar(n);
+                if (c == ' ' || c == '\n' || c == '\0')
+                {
+                    var literal = Window.GetAndConsumeChars(n);
+                    return PureTokenFactory.CreateUnquotedStringLiteral(literal);
+                }
+
+                n++;
+            }
+        }
+
+        private static readonly HashSet<string> Keywords;
+        
+        static MLexer()
+        {
+            Keywords = new HashSet<string>
+            {
+                "for", "if", "function", "while", "case", "try", "catch", "end",
+                "switch", "classdef", "elseif", "persistent",
+            };
+        }
+
         private PureToken LexTokenWithoutTrivia(List<Trivia> leadingTrivia)
         {
             var character = Window.PeekChar();
+            if (character == '\0')
+            {
+                return PureTokenFactory.CreateEndOfFileToken();
+            }
+
+            if (TokensSinceNewLine == 1
+                && LastToken.Kind == TokenKind.Identifier
+                && LastToken.TrailingTrivia.Any()
+                && character != '='
+                && character != '('
+                && !Keywords.Contains(LastToken.PureToken.LiteralText))
+            {
+                return ContinueParsingUnquotedStringLiteral();
+            }
+            if (LastToken?.Kind == TokenKind.UnquotedStringLiteral &&
+                TokensSinceNewLine > 0)
+            {
+                return ContinueParsingUnquotedStringLiteral();
+            }
             switch (character)
             {
                 case 'a':

Lexer/PureTokenFactory.cs

@@ -93,6 +93,11 @@
             return new PureToken(TokenKind.DoubleQuotedStringLiteral, "\"" + s + "\"", s, Window.Position);
         }
 
+        public PureToken CreateUnquotedStringLiteral(string s)
+        {
+            return new PureToken(TokenKind.UnquotedStringLiteral, s, s, Window.Position);
+        }
+
         public PureToken CreateEndOfFileToken()
         {
             return new PureToken(TokenKind.EndOfFile, "", null, Window.Position);