Lecture 06: Describing Language Syntax

 0    11 tarjetas    up804653
descargar mp3 imprimir jugar test de práctica
 
término English definición English
what are regular grammars
empezar lección
regular grammars (equivalently, regular expressions) are useful for defining languages’ lexical structure;
what re context-free grammars
empezar lección
context-free grammars (CFG) for defining language syntax.
CFG is the ___ ___ used way to describe programming language.
empezar lección
CFG is the most widely used way to describe programming language.
what is the formal definition for CFG
empezar lección
a context-free grammar is a tuple G = (T, N, S,P)
if a context-free grammar is a tuple G = (T, N, S,P) what is T
empezar lección
T is a finite nonempty set of terminal symbols, which consist of strings in the language (such as while), which refer to parts of the text of sentences in the language.
if a context-free grammar is a tuple G = (T, N, S,P) what is N
empezar lección
N is a finite nonempty set of non-terminal symbols, disjoint from T. These refer to syntactic structures defined by other structures and rules (e.g., <exp>).
if a context-free grammar is a tuple G = (T, N, S,P) what is S
empezar lección
S ∈ N (the start symbol),
if a context-free grammar is a tuple G = (T, N, S,P) what is P
empezar lección
P is a set of (context-free) productions of the form A → α (reads A produces α) where A ∈ N and α ∈ (T ∪ N)∗.
What is the standard shorthand notation for context-free grammars (CFG)
empezar lección
[1] The start symbol is that given on the left-hand-side of the first rule. [2] For each non-terminal symbol we use | to separate the alternative right-hand sides of the production rules.
write G2 in short hand G2 = (T, N, S, P) where T = {a, b}, N = {S, C} and P ={S →ε, S →C, S →aSa, S →bSb, C → a, C → b}.
empezar lección
G2 can be written as follows: S → ε | C | aSa | bSb C → a | b
What does BNF stand for?
empezar lección
Backus-Naur Form

Debes iniciar sesión para poder comentar.