// Homework 5 solution
//   J. Dean Brock

COMPILER tingle

CHARACTERS
  letter     = 'A'..'Z' + 'a'..'z' .
  digit      = '0'..'9' .

TOKENS
  hostname   = letter { letter } .
  number     = digit { digit } .
  compare    = '<' | '>' .
  updown     = '+' | '-' .

IGNORE '\t' + '\r' + ' '

PRODUCTIONS
  TingleExpr =
        TingleTerm
	{ 
	  '|'                  (. System.out.print("| ") ; .)
	  TingleTerm
	}
	.

  TingleTerm =
	TingleFactor
	{ 
          "&"                  (. System.out.print("& ") ; .)
	  TingleFactor
	}
	.

  TingleFactor = 
        (
	  TingleTest
	| 
	  '~'                  (. System.out.print("~ ") ; .)
	  TingleFactor
	| 
	  '('                  (. System.out.print("( ") ; .)
	  TingleExpr
	  ')'                  (. System.out.print(") ") ; .)
        )
	.

  TingleTest =
        updown
        hostname
        "["
        compare
        number
        "]"
        .

  tingle  =
        {
          TingleExpr
          '\n'                  (. System.out.println() ; .)
        }
        .

END tingle .