LL parser / What is LL(n)
Top-down parser. Parses input from Left to right. Constructs a Leftmost derivation of the sentence.
The notation LL(n) means that the Parser looks ahead n tokens when parsing a sentence.
LL(1) are of great practical interest, since they are easy to construct and many languages are designed to be LL(1) because of this.
Implementation can be using:
- table parsers
- recursive descent parsers
S -> E E -> (E + E) E -> i
Leftmost derivation for
w = ((i + i) + i) is: S => E => (E + E) => ((E + E) + E) => ((i + E) + E) => ((i + i) + E) => ((i + i) + i)