A compiler tool to accept a string if it's accepted in the grammar of program
imagine you have a grammar like
E --> TR
R --> +TR | ε
T --> FM
M --> FM | ε
F --> (E) | id
start writing a string in this program and if it belongs to the grammer it'll be accepted otherwise you'll face with an error!
try this string and it should be accepted
idid+(id)+id*(id)+id*id+(id)