Grammophone, a context-free grammar checker

Grammophone is a tool for analyzing and transforming context-free grammars. To start, enter a grammar and click Analyze or Transform.

Example Grammars

Arithmetic Expressions

exp -> exp "+" term | term .
term -> term "*" factor | factor .
factor -> "(" exp ")" | number .

Analyze

Dangling Else

statement -> if_stmt | other .
if_stmt -> if "(" cond ")" statement |
  if "(" cond ")" statement else statement .
cond -> true | false .

Analyze