cfgrammar 0.0.9.3

Context-free grammars and parsing

cfgrammar : Context-free grammars, parsing and semantic

Table of Contents

• Main Features
• Example

Main features

• Grammar properties
  • accessible and productive rules / variables
  • ε-productive rules / variables
  • reduced grammar
  • "First" and "Follow" sets
• LL1 parsing
  • computes and displays LL(1) table
  • constructs parser
• LR parsing
  • computes and displays LR(0) automaton
  • constructs LR(0), SLR(1), LALR(1) tables and parsers
• Semantic
  • parsing with semantic actions
• Abstract Syntax Tree
  • predefined semantic classes to produce AST
    • Graphviz / dot output
    • Latex + Tikz output

Example

from cfgrammar import Grammar

g = Grammar.from_string('S -> ( S ) S | a')

print(g)
print('productives variables : ', g.productive.vars)
print('Follow sets : ', g.follow)