Syntax

Bop’s syntax is deliberately simple. If you’ve seen JavaScript or Python, most of it will look familiar.

Blocks

Code blocks use curly braces { } and only appear after control flow keywords (if, else, while, for, repeat, fn):

if count > 3 {
  print("That's a lot!")
}

Important: The opening { must be on the same line as its keyword. Bop automatically inserts semicolons at the end of lines, so putting { on the next line would cause a parse error.

// Good
if count > 3 {
  print("Nice!")
}

// Bad — will cause an error
if count > 3
{
  print("Nice!")
}

Statements

Statements end with a newline. Bop automatically inserts semicolons after lines ending in an identifier, literal, true, false, none, break, continue, return, ), ], or }.

You can put multiple statements on one line with an explicit semicolon:

let x = 1; let y = 2

Comments

Line comments start with //. Everything after // on that line is ignored:

// This is a comment
let x = 5   // So is this

Identifiers

Variable and function names start with a letter or underscore and can contain letters, digits, and underscores:

let my_var = 5
let _count = 0
let item3 = "hello"

Whitespace

Spaces and tabs are insignificant — use whatever indentation style you like. Only newlines matter (they end statements).