In an old programming language project of mine, I wanted to use something similar to S-expressions for most of the grammar because they are very universal and f

In an old programming language project of mine, I wanted to use something similar to S-expressions for most of the grammar because they are very universal and flexible, but I didn’t like having too many parentheses, so I extended the syntax by allowing semicolons as an alternative. So, in pseudocode: (print (+ 1 2)) (exit 1) becomes: print (1 + 2); // "+" is the 2nd place because it's a method call on "1" exit 1; Both variants are valid; semicolons are just syntactic sugar to reduce the number of parentheses. In the AST, they represent the exact same expressions. For function bodies, I also introduced an extension to make lambdas stand out more from the rest of the code by using curly braces: (0 to 10) loop ^(i) { print i; // Internally transformed to (print i) } // clarification: // 1. The "to" method of the 0 object creates a Range object, which has a "loop" method that accepts a lambda. // 2. The ^ symbol is just a shorthand for "lambda". As you can see, this wasn't a Lisp dialect (and I'm no expert at Lisps), but I liked the idea of having a universal expression structure in the AST, however I eventually ended up extending it with two additional modifications that made it more readable (at least for me)