Lexical structure

Comments and statement separators: the two most basic rules of XS source text.

Summary

Line comments start with --; block comments use {- and -} and nest correctly, so you can comment out code that already contains block comments. Shebang lines (#!/usr/bin/env xs) are silently ignored. Statements are separated by newlines or semicolons; both forms work anywhere, including inside blocks.

Canonical

-- line comment (everything after -- is ignored)

{- block comment (nestable: {- inner -} works fine) -}

#!/usr/bin/env xs   -- shebang line, silently ignored by the interpreter

let a = 1
let b = 2

let x = 10; let y = 20; let z = x + y

-- semicolons inside blocks
if true { let p = 1; let q = 2 }

-- extra semicolons are fine
let val = 42;;;