> The idea of describing the structure of language using rewriting rules can be traced back to at least the work of Pāṇini (who lived sometime between the 7th and 4th century BC). His notation to describe Sanskrit word structure notation is equivalent in power to that of Backus and has many similar properties.
Comparison with modern formal systems
Pāṇini's grammar is the world's first formal system, developed well before the 19th century innovations of Gottlob Frege and the subsequent development of mathematical logic. In designing his grammar, Pāṇini used the method of "auxiliary symbols", in which new affixes are designated to mark syntactic categories and the control of grammatical derivations. This technique, rediscovered by the logician Emil Post, became a standard method in the design of computer programming languages. Sanskritists now accept that Pāṇini's linguistic apparatus is well-described as an "applied" Post system. Considerable evidence shows ancient mastery of context-sensitive grammars, and a general ability to solve many complex problems. Frits Staal has written that "Panini is the Indian Euclid."
From https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form
> The idea of describing the structure of language using rewriting rules can be traced back to at least the work of Pāṇini (who lived sometime between the 7th and 4th century BC). His notation to describe Sanskrit word structure notation is equivalent in power to that of Backus and has many similar properties.
https://en.wikipedia.org/wiki/P%C4%81%E1%B9%87ini
Comparison with modern formal systems Pāṇini's grammar is the world's first formal system, developed well before the 19th century innovations of Gottlob Frege and the subsequent development of mathematical logic. In designing his grammar, Pāṇini used the method of "auxiliary symbols", in which new affixes are designated to mark syntactic categories and the control of grammatical derivations. This technique, rediscovered by the logician Emil Post, became a standard method in the design of computer programming languages. Sanskritists now accept that Pāṇini's linguistic apparatus is well-described as an "applied" Post system. Considerable evidence shows ancient mastery of context-sensitive grammars, and a general ability to solve many complex problems. Frits Staal has written that "Panini is the Indian Euclid."