2017-10-25 13:45:44 +02:00
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(* a simple program syntax in EBNF − Wikipedia *)
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program = 'PROGRAM', white space, identifier, white space,
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'BEGIN', white space,
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{ assignment, ";", white space },
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'END.' ;
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identifier = alphabetic character, { alphabetic character | digit } ;
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number = [ "-" ], digit, { digit } ;
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2017-10-28 19:16:00 +02:00
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string = '"' , { all characters }, '"' ;
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2017-10-25 13:45:44 +02:00
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assignment = identifier , ":=" , ( number | identifier | string ) ;
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alphabetic character = "A" | "B" | "C" | "D" | "E" | "F" | "G"
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| "H" | "I" | "J" | "K" | "L" | "M" | "N"
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| "O" | "P" | "Q" | "R" | "S" | "T" | "U"
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| "V" | "W" | "X" | "Y" | "Z" ;
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digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
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white space = ? white space characters ? ;
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all characters = ? all visible characters ? ;
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