Definition of language-compilation principle
Given a grammar G=(V T ,V N ,P,S) , if α→β∈P, then the α in the γαδ in the symbol string can be replaced by β, which is denoted as γαδ⇒γβδ , which is called γαδ directly Derive γβδ.
Deduction ( derivation ) and reduction ( reduction )
From the above examples, it can be seen that derivation is a top-down process, and statutes are self-directed processes, in other words: derivation is from abstract to concrete, and statutes are from concrete to abstract
Sentence patterns and sentences
Formal definition of language
The set of all sentences derived from the beginning symbol S of grammar G is called the language generated by grammar G , which is denoted as
The generated language called grammar G is written as
