les is an actively used grammar language. LES is an interchange format for syntax trees, comparable to s-expressions but designed for languages in the Algol family such as C, C++, C#, Java, EcmaScript, Rust and Python. It can be described as “JSON for code”: just as XML/YAML/JSON are tree structures that assign no particular meaning to the data inside, likewise LES represents syntax trees without assigning any particular meaning to them.

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Example code from the web:

fn factorial(x::int)::int {
  var result = 1;
  for (; x > 1; x--) {
    result *= x;
  return result;

Last updated August 9th, 2020

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