Support for comments

Upsilon/Parser/Lexer.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Collections.Immutable;
 using System.Text;
 using Upsilon.Text;
@@ -57,6 +56,11 @@ namespace Upsilon.Parser
                 case '+':
                     return new SyntaxToken(SyntaxKind.Plus, _position, "+", null);
                 case '-':
+                    if (Next == '-')
+                    {
+                        _position++;
+                        return LexComments();
+                    }
                     return new SyntaxToken(SyntaxKind.Minus, _position, "-", null);
                 case '*':
                     return new SyntaxToken(SyntaxKind.Star, _position, "*", null);
@@ -179,5 +183,21 @@ namespace Upsilon.Parser
             }
             return new SyntaxToken(kind, start, str, null);
         }
+
+        private SyntaxToken LexComments()
+        {
+            var start = _position;
+            var stringBuilder = new StringBuilder();
+            if (Current != ' ')
+                stringBuilder.Append(Current);
+            while (Next != '\n' && Next != '\0')
+            {
+                stringBuilder.Append(Next);
+                _position++;
+            }
+
+            var str = stringBuilder.ToString();
+            return new SyntaxToken(SyntaxKind.Comment, start, str, str);
+        }
     }
 }

Upsilon/Parser/Parser.cs

@@ -27,11 +27,19 @@ namespace Upsilon.Parser
         private SyntaxToken Current => Get(0);
         private SyntaxToken Next => Get(1);
 
-        private SyntaxToken Get(int offset)
+        private SyntaxToken Get(int offset, bool allowComment = false)
         {
-            return _position + offset >= _tokens.Length
+            if (_position + offset >= _tokens.Length)
-                ? new SyntaxToken(SyntaxKind.EndOfFile, _position + offset, "\0", null)
+                return new SyntaxToken(SyntaxKind.EndOfFile, _position + offset, "\0", null);
-                : _tokens[_position                               + offset];
+            else
+            {
+                var token = _tokens[_position + offset];
+                if (token.Kind == SyntaxKind.Comment && !allowComment)
+                {
+                    return Get(offset + 1);
+                }
+                return token;
+            }
         }
 
         private SyntaxToken NextToken()

Upsilon/Parser/SyntaxKind.cs

@@ -7,6 +7,7 @@ namespace Upsilon.Parser
         EndOfFile,
         WhiteSpace,
         BadToken,
+        Comment,
 
         // tokens
         Number,
@@ -80,6 +81,6 @@ namespace Upsilon.Parser
         TableAssignmentStatement,
         NumericForStatement,
         BreakStatement,
-        GenericForStatement
+        GenericForStatement,
     }
 }