Add some comments

ConsoleDemo/Program.cs

@@ -153,11 +153,11 @@ namespace ConsoleDemo
 
         public static void Main(string[] args)
         {
-            ParserDemo();
+            //ParserDemo();
             //SemanticsDemo();
             //ContextDemo();
             //DumbPrinterDemo();
-            //UsageDemo();
+            UsageDemo();
             Console.ReadKey();
         }
     }

Parser/Internal/GreenNode.cs

@@ -19,7 +19,7 @@ namespace Parser.Internal
         
         public GreenNode(TokenKind kind, int slots)
         {
-            Kind =kind;
+            Kind = kind;
             Slots = slots;
         }
                 

Parser/TokenKind.cs

@@ -1,115 +1,273 @@
 namespace Parser
 {
+    // We use the same set of kinds for syntax tokens & syntax nodes.
     public enum TokenKind
     {
+        // SYNTAX TOKENS
+
         None = 0,
+        // The lexer puts a virtual "end of file" token at the end of the parsed file.
         EndOfFile = 1,
+        // Identifier: could be a reserved word, a variable name, a class name, etc.
         Identifier = 2,
+        // Number literal: 123, 45.678, 2e-5, etc.
         NumberLiteral = 3,
+        // String literal: 'abc', '123', etc. The "usual" string literals are single-quoted and are just char arrays.
         StringLiteral = 4,
+        // Double-quoted string literal: "abc", "123", etc. These are the "new" string literal that are more like strings
+        // and less like char arrays (for example, char arrays could be columns instead of rows, or even multi-dimensional).
         DoubleQuotedStringLiteral = 5,
+        // This is for supporting "command statements" like
+        // > cd some/+folder/
+        // In this example, "some/folder" should be treated as a string literal (for example, "+' there should be a part
+        // of it, and not parsed as a binary operator).
         UnquotedStringLiteral = 6,
         
         // trivia
         
+        // Spaces, tabs, etc.
         Whitespace = 10,
+        // New line characters.
         Newline = 11,
+        // There are three types of comments:
+        // * comments starting with % and lasting till the end of the line;
+        // * comments starting with %{ and ending with %}, possibly spanning several lines;
+        // * comments starting with ... and lasting till the end of the line.
+        // At the moment, this token is used to accomodate all of them, so the other two
+        // (MultilineComment = 13 and DotDotDot = 56 are not used).
         Comment = 12,
+        // Comments starting with %{ and ending with %}, possibly spanning several lines. Not used, see Comment = 12.
         MultilineComment = 13,
         
+        // operators
+
+        // =
         Assignment = 20,
+        // ==
         Equality = 21,
+        // ~=
         Inequality = 22,
+        // &&
         LogicalAnd = 23,
+        // ||
         LogicalOr = 24,
+        // &
         BitwiseAnd = 25,
+        // |
         BitwiseOr = 26,
+        // <
         Less = 27,
+        // <=
         LessOrEqual = 28,
+        // >
         Greater = 29,
+        // >=
         GreaterOrEqual = 30,
+        // ~
         Not = 31,
+        // +
         Plus = 32,
+        // -
         Minus = 33,
+        // *
         Multiply = 34,
+        // /
         Divide = 35,
+        // ^
         Power = 36,
+        // \
         Backslash = 37,
+        // ' (this is the same as starting string literal; we'll have some fun distinguishing those).
         Transpose = 38,
+        // .*
         DotMultiply = 39,
+        // ./
         DotDivide = 40,
+        // .^
         DotPower = 41,
+        // .\
         DotBackslash = 42,
+        // .'
         DotTranspose = 43,
+        // @
         At = 44,
+        // :
         Colon = 45,
+        // ?
         QuestionMark = 46,
+        // ,
         Comma = 47,
+        // ;
         Semicolon = 48,
+        // {
         OpeningBrace = 49,
+        // }
         ClosingBrace = 50,
+        // [
         OpeningSquareBracket = 51,
+        // ]
         ClosingSquareBracket = 52,
+        // (
         OpeningBracket = 53,
+        // )
         ClosingBracket = 54,
+        // .
         Dot = 55,
+        // Comments starting with ... and lasting till the end of the line.  Not used, see Comment = 12.
         DotDotDot = 56,
-        // unary tokens are not recognized during lexing; they are contextually recognized while parsing.
+        // Unary tokens are not recognized during lexing; they are contextually recognized while parsing.
         UnaryPlus = 57,
         UnaryMinus = 58,
         UnaryNot = 59,
         UnaryQuestionMark = 60,
-        // syntax nodes
+
+        // SYNTAX NODES
+        // The whole file.
         File = 100,
+        // a list of syntax nodes and/or tokens.
         List,
+        // [output1, output2] = function(input1, input2)
+        // <...>
+        // end
         FunctionDeclaration,
+        // (input1, input2)
         FunctionInputDescription,
+        // [output1, output2] =
         FunctionOutputDescription,
+        // switch a
+        //     case 1
+        // <...>
+        // end
         SwitchStatement,
+        // case 1
+        //     doSomething();
         SwitchCase,
+        // while a < 10
+        //     doSomething();
+        // end
         WhileStatement,
+        // if a < 5
+        //     doSomething();
+        // elseif a > 10
+        //     doSomethingElse();
+        // else
+        //     GiveUp();
+        // end
         IfStatement,
+        // elseif a > 10
+        //     doSomethingElse();
         ElseifClause,
+        // else
+        //     GiveUp();
         ElseClause,
+        // for a = 1:5
+        //     process(a);
+        // end
         ForStatement,
+        // a = 1:5
         AssignmentExpression,
+        // catch e
+        //     dealWithIt(e);
+        // end
         CatchClause,
+        // try
+        //     somethingWeird();
+        // catch e
+        //     dealWithIt(e);
+        // end
         TryCatchStatement,
+        // a = 5;
         ExpressionStatement,
+        // 
         EmptyStatement,
+        // 
         EmptyExpression,
+        // -13
         UnaryPrefixOperationExpression,
+        // some.complex.name
         CompoundName,
+        // @func
         NamedFunctionHandle,
+        // @(x) x + 1
         Lambda,
+        // +
         BinaryOperation,
+        // a
         IdentifierName,
+        // 123
         NumberLiteralExpression,
+        // 'abc'
         StringLiteralExpression,
+        // "abc"
         DoubleQuotedStringLiteralExpression,
+        // abc
         UnquotedStringLiteralExpression,
+        // [1, 2; 3 4]
         ArrayLiteralExpression,
+        // {1, 3, 'abc'}
         CellArrayLiteralExpression,
+        // (1 + 2 * 3)
         ParenthesizedExpression,
+        // abc{2}
         CellArrayElementAccess,
+        // doSomething(5)
         FunctionCall,
+        // object.member
         MemberAccess,
+        // [1 2 3]'
         UnaryPostfixOperationExpression,
+        // struct.(field)
         IndirectMemberAccess,
+        // cd some/+folder/
         Command,
+        // method@SuperClass(object)
         ClassInvokation,
+        // = true
         AttributeAssignment,
+        // Sealed = true
         Attribute,
+        // (Sealed = true)
         AttributeList,
+        // function result = method(obj)
+        //     <...>
+        // end
         MethodDefinition,
+        // methods
+        //     function result = method(obj)
+        //     <...>
+        //     end
+        // end
         MethodsList,
+        // properties
+        //     x
+        //     y
+        // end
         PropertiesList,
+        // < BaseClass, AnotherBaseClass
         BaseClassList,
+        // classdef MyClass < BaseClass, AnotherBaseClass
+        //     properties
+        //         y
+        //     end
+        //     methods
+        //         <...>
+        //     end
+        // end
         ClassDeclaration,
+        // (1)
         EnumerationItemValue,
+        // One (1)
         EnumerationItem,
+        // enumeration
+        //     One (1)
+        //     Two (2)
+        // end
         EnumerationList,
+        // result = abstractMethod(object)
         AbstractMethodDeclaration,
+        // events
+        //     ToggleSomething
+        // end
         EventsList,
     }
 }