BLOCK = "{", { COMMAND }, "}" ;
COMMAND = ( λ | ASSIGNMENT | PRINT | BLOCK | WHILE | IF, TYPE), ";" ;
WHILE = "while", "(", OREXPR ,")", COMMAND;
IF = "if", "(", OREXPR ,")", COMMAND, (("else", COMMAND) | λ );
ASSIGNMENT = IDENTIFIER, "=", EXPRESSION ;
TYPE = TYPES, IDENTIFIER ;
PRINT = "println", "(", OREXPR, ")" ;
OREXPR = ANDEXPR, { "||", ANDEXPR } ;
ANDEXPR = EQEXPR, { "&&", EQEXPR } ;
EQEXPR = RELEXPR, { "==", RELEXPR } ;
RELEXPR = EXPRESSION, { (">"|"<"), EXPRESSION }
EXPRESSION = TERM, { ("+" | "-"), TERM } ;
TERM = FACTOR, { ("*" | "/"), FACTOR } ;
FACTOR = (("+" | "-" | "!" ), FACTOR) | NUMBER | "(", OREXPR, ")" | IDENTIFIER | READLN;
READLN = "readln", "(",")";
IDENTIFIER = LETTER, { LETTER | DIGIT | "_" } ;
NUMBER = DIGIT, { DIGIT } ;
LETTER = ( a | ... | z | A | ... | Z ) ;
DIGIT = ( 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 0 ) ;
TYPES = ("int" | "bool", "string") ;
BOOL = ("true" | "false" )
