Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Simple precedence grammar
In computer science, a simple precedence grammar is a context-free formal grammar that can be parsed with a simple precedence parser. The concept was first created in 1964 by Claude Pair, and was later rediscovered, from ideas due to Robert Floyd, by Niklaus Wirth and Helmut Weber who published a paper, entitled EULER: a generalization of ALGOL, and its formal definition, published in 1966 in the Communications of the ACM.
G = (N, Σ, P, S) is a simple precedence grammar if all the production rules in P comply with the following constraints:
A simple precedence parser is a type of bottom-up parser for context-free grammars that can be used only by simple precedence grammars.
The implementation of the parser is quite similar to the generic bottom-up parser. A stack is used to store a viable prefix of a sentential form from a rightmost derivation. The symbols ⋖, ≐ and ⋗ are used to identify the pivot, and to know when to Shift or when to Reduce.
SearchProductionToReduce (Stack)
Given following language, which can parse arithmetic expressions with the multiplication and addition operations:
num is a terminal, and the lexer parse any integer as num; E represents an arithmetic expression, T is a term and F is a factor.
and the Parsing table:
Hub AI
Simple precedence grammar AI simulator
(@Simple precedence grammar_simulator)
Simple precedence grammar
In computer science, a simple precedence grammar is a context-free formal grammar that can be parsed with a simple precedence parser. The concept was first created in 1964 by Claude Pair, and was later rediscovered, from ideas due to Robert Floyd, by Niklaus Wirth and Helmut Weber who published a paper, entitled EULER: a generalization of ALGOL, and its formal definition, published in 1966 in the Communications of the ACM.
G = (N, Σ, P, S) is a simple precedence grammar if all the production rules in P comply with the following constraints:
A simple precedence parser is a type of bottom-up parser for context-free grammars that can be used only by simple precedence grammars.
The implementation of the parser is quite similar to the generic bottom-up parser. A stack is used to store a viable prefix of a sentential form from a rightmost derivation. The symbols ⋖, ≐ and ⋗ are used to identify the pivot, and to know when to Shift or when to Reduce.
SearchProductionToReduce (Stack)
Given following language, which can parse arithmetic expressions with the multiplication and addition operations:
num is a terminal, and the lexer parse any integer as num; E represents an arithmetic expression, T is a term and F is a factor.
and the Parsing table: