Ancient Roots of BNF Posted by willwinger on Saturday June 29, 2019 @01:25AM from the blogs.scientificamerican.com dept. https://blogs.scientificamerican.com/roots-of-unity/a-feat-of-mathematical-eponymy/ ( 1 comment | 2 points | on HN )
There is both left and right recursion in the definition of <number>, but this EBNF (Wirth notation) uses iteration only:
number = digit { digit } [ "." digit { digit } ] .