Embedded Systems Group (ES)

Algorithms for Context-Free Grammars

Using this tool, you can apply several transformations on context-free grammars like basic clean-ups (no ϵ-productions, no chain productions, no unreachable symbols, no unproductive symbols), elimination of left recursion and the elimination of left factors.

Moreover, you find tools for computing the First and Follow sets of all nonterminals to construct parse tables for top-down parsers of LL(1) grammars.

Nonterminals are given by uppercase letters, while all other single characters except for -,>,|,ϵ are viewed as terminal symbols. The left-hand side nonterminal of the first rule is the start symbol.

See also some example grammars.

grammar rules
word to parse