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|
letter_uppercase = "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"
;
letter_lowercase = "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"
;
letter = letter_uppercase | letter_lowercase
;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
;
identifier = letter , { letter | digit }
;
numeral = digit | ( numeral , digit )
;
variable = identifier
;
arithmetic_operation = "+" | "-" | "*"
;
arithmetic_expression = ( "(" , arithmetic_expression , arithmetic_operation , arithmetic_expression , ")" )
| variable | numeral ;
boolean_operation = "or" | "not"
;
relational_operation = "=" | "#" | "<" | "<=" | ">" | ">="
;
boolean_expression = ( "(" , boolean_expression , boolean_operation , boolean_expression , ")" )
| ( "not" , boolean_expression )
| ( arithmetic_expression , relational_operation , arithmetic_expression )
;
statement = "skip"
| ( variable , ":=" , arithmetic_expression )
| ( "(" , statement , ";" , "statement" , ")" )
| ( "if" , boolean_expression , "then" , statement , "else" , statement , "end" )
| ( "while" , boolean_expression , "do" , statement , "end" )
| ( "var" , variable , ":=", arithmetic_expression , "in" , statement , "end" )
;
|
