Smalltalk Grammar

http://chronos-st.blogspot.com/2007/12/smalltalk-in-one-page.html
http://www.csci.csusb.edu/dick/samples/smalltalk.syntax.html

Formal EBNF Specification of Smalltalk Syntax

   1. Character = ? Any Unicode character ?;
   2. WhitespaceCharacter = ? Any space, newline or horizontal tab character ?;
   3. DecimalDigit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9";
   4. Letter = "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M"
                      | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z"
                      | "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m"
                      | "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z";
   5. CommentCharacter = Character - '"';
              (* Any character other than a double quote *)
   6. Comment = '"', {CommentCharacter}, '"';
   7. OptionalWhitespace = {WhitespaceCharacter | Comment};
   8. Whitespace = (WhitespaceCharacter | Comment), OptionalWhitespace;
   9. LetterOrDigit =
                      DecimalDigit
                      | Letter;
  10. Identifier = (Letter | "_"), {(LetterOrDigit | "_")};
  11. Reference = Identifier;
  12. ConstantReference =
                      "nil"
                      | "false"
                      | "true";
  13. PseudoVariableReference =
                      "self"
                      | "super"
                      | "thisContext";
              (* "thisContext" is not defined by the ANSI Standard, but is widely used anyway *)
  14. ReservedIdentifier =
                      PseudoVariableReference
                      | ConstantReference;
  15. BindableIdentifier = Identifier - ReservedIdentifier;
  16. UnaryMessageSelector = Identifier;
  17. Keyword = Identifier, ":";
  18. KeywordMessageSelector = Keyword, {Keyword};
  19. BinarySelectorChar = "~" | "!" | "@" | "%" | "&" | "*" | "-" | "+" | "=" | "|" | "\" | "<" | ">" | "," | "?" | "/";
  20. BinaryMessageSelector = BinarySelectorChar, [BinarySelectorChar];

  21. IntegerLiteral = ["-"], UnsignedIntegerLiteral;
  22. UnsignedIntegerLiteral =
                      DecimalIntegerLiteral
                      | Radix, "r", BaseNIntegerLiteral;
  23. DecimalIntegerLiteral = DecimalDigit, {DecimalDigit};
  24. Radix = DecimalIntegerLiteral;
  25. BaseNIntegerLiteral = LetterOrDigit, {LetterOrDigit};
  26. ScaledDecimalLiteral = ["-"], DecimalIntegerLiteral, [".", DecimalIntegerLiteral], "s", [DecimalIntegerLiteral];
  27. FloatingPointLiteral = ["-"], DecimalIntegerLiteral, (".", DecimalIntegerLiteral, [Exponent] | Exponent);
  28. Exponent = ("e" | "d" | "q"), [["-"], DecimalIntegerLiteral];
  29. CharacterLiteral = "$", Character;
  30. StringLiteral = "'", {StringLiteralCharacter | "''"}, "'";
              (* To embed a "'" character in a String literal, use two consecutive single quotes *)
  31. StringLiteralCharacter = Character - "'";
              (* Any character other than a single quote *)
  32. SymbolInArrayLiteral =
                      UnaryMessageSelector - ConstantReference
                      | KeywordMessageSelector
                      | BinaryMessageSelector;
  33. SymbolLiteral = "#", (SymbolInArrayLiteral | ConstantReference | StringLiteral);
  34. ArrayLiteral =
                      ObjectArrayLiteral
                      | ByteArrayLiteral;
  35. ObjectArrayLiteral = "#", NestedObjectArrayLiteral;
  36. NestedObjectArrayLiteral = "(", OptionalWhitespace, [LiteralArrayElement, {Whitespace, LiteralArrayElement}], OptionalWhitespace, ")";
  37. LiteralArrayElement =
                      Literal - BlockLiteral
                      | NestedObjectArrayLiteral
                      | SymbolInArrayLiteral
                      | ConstantReference;
  38. ByteArrayLiteral = "#[", OptionalWhitespace, [UnsignedIntegerLiteral, {Whitespace, UnsignedIntegerLiteral}], OptionalWhitespace,"]";

      (* The preceding production rules would usually be handled by the lexical analyzer;
           the following production rules would usually be handled by the parser *)
  39. FormalBlockArgumentDeclaration = ":", BindableIdentifier;
  40. FormalBlockArgumentDeclarationList = FormalBlockArgumentDeclaration, {Whitespace, FormalBlockArgumentDeclaration};
  41. BlockLiteral = "[", [OptionalWhitespace, FormalBlockArgumentDeclarationList, OptionalWhitespace, "|"], ExecutableCode, OptionalWhitespace, "]";

  42. Literal = ConstantReference
                      | IntegerLiteral
                      | ScaledDecimalLiteral
                      | FloatingPointLiteral
                      | CharacterLiteral
                      | StringLiteral
                      | SymbolLiteral
                      | ArrayLiteral
                      | BlockLiteral;

  43. NestedExpression = "(", Statement, OptionalWhitespace, ")";
  44. Operand =
                      Literal
                      | Reference
                      | NestedExpression;

  45. UnaryMessage = UnaryMessageSelector;
  46. UnaryMessageChain = {OptionalWhitespace, UnaryMessage};
  47. BinaryMessageOperand = Operand, UnaryMessageChain;
  48. BinaryMessage = BinaryMessageSelector, OptionalWhitespace, BinaryMessageOperand;
  49. BinaryMessageChain = {OptionalWhitespace, BinaryMessage};
  50. KeywordMessageArgument = BinaryMessageOperand, BinaryMessageChain;
  51. KeywordMessageSegment = Keyword, OptionalWhitespace, KeywordMessageArgument;
  52. KeywordMessage = KeywordMessageSegment, {OptionalWhitespace, KeywordMessageSegment};
  53. MessageChain =
                      UnaryMessage, UnaryMessageChain, BinaryMessageChain, [KeywordMessage]
                      | BinaryMessage, BinaryMessageChain, [KeywordMessage]
                      | KeywordMessage;
  54. CascadedMessage = ";", OptionalWhitespace, MessageChain;
  55. Expression = Operand, [OptionalWhitespace, MessageChain, {OptionalWhitespace, CascadedMessage}];

  56. AssignmentOperation = OptionalWhitespace, BindableIdentifier, OptionalWhitespace, ":=";
  57. Statement = {AssignmentOperation}, OptionalWhitespace, Expression;
  58. MethodReturnOperator = OptionalWhitespace, "^";
  59. FinalStatement = [MethodReturnOperator], Statement;
  60. LocalVariableDeclarationList = OptionalWhitespace, "|", OptionalWhitespace, [BindableIdentifier, {Whitespace, BindableIdentifier}], OptionalWhitespace, "|";
  61. ExecutableCode = [LocalVariableDeclarationList], [{Statement, OptionalWhitespace, "."}, FinalStatement, ["."]];

  62. UnaryMethodHeader = UnaryMessageSelector;
  63. BinaryMethodHeader = BinaryMessageSelector, OptionalWhitespace, BindableIdentifier;
  64. KeywordMethodHeaderSegment = Keyword, OptionalWhitespace, BindableIdentifier;
  65. KeywordMethodHeader = KeywordMethodHeaderSegment, {Whitespace, KeywordMethodHeaderSegment};
  66. MethodHeader =
                      UnaryMethodHeader
                      | BinaryMethodHeader
                      | KeywordMethodHeader;
  67. MethodDeclaration = OptionalWhiteSpace, MethodHeader, ExecutableCode;