grammar.txt

prog    ::= word "(" ")" block ;
decls   ::= decls decl | ;
decl    ::= vtype word ";" ;
vtype   ::= int | char ;
block   ::= "{" decls slist "}" | ;
slist   ::= slist stat
        | stat ;
stat    ::= IF cond THEN block ELSE block
        | word "=" expr ";"
        | EXIT expr ";"
        | ;
cond    ::= expr "<" expr ;
expr    ::= expr "+" fact
        | expr "*" fact
        | fact ;
fact    ::= num
        | word ;
word    ::= ([a-z] | [A-Z])* ;
num     ::= [0-9]* ;