The class of grammar-based codes is very broad.

The basic task of grammar-based codes is constructing a context-free grammar deriving a single string.

Grammar-based codes are universal in the sense that they can achieve asymptotically the entropy rate of any stationary, ergodic source with a finite alphabet.

To compress a data sequence , a grammar-based code transforms into a context-free CFG .

Grammar-based codes or Grammar-based compression are compression algorithms based on the idea of constructing a context-free grammar (CFG) for the string to be compressed.

The class of grammar-based codes are gaining popularity because they can extremely compress highly repetitive text, for instance, biological data collection of same or related species, huge versioned document collection, internet archives, etc.