Grammar:
Pqm = Lsent ';' Sent
Pqm = Sent
Sent = 'if' Eb 'then' Lsent 'end'
Sent = 'if' Eb 'then' Lsent 'else' Lsent 'end'
Sent = 'for' Atr 'to' Ea 'repeat' Lsent 'end'
Atr = 'id' '=' Expr
Expr = Eb
Eb = Eb 'boolop' Tb
Eb = Tb
Tb = 'not' Tb
Tb = 'true'
Tb = 'false'
Tb = Ea
Ea = Ea 'aritop' Ta
Ea = Ta
Ta = Ta 'multop' Fa
Ta = Fa
Fa = '(' Expr ')'
Fa = 'id'
Fa = 'cteN'\