A Prettier Formatter for Catspeak

Once men turned their thinking over to machines in the hope that this would set them free. But that only permitted other men with machines to enslave them.

An unofficial extension for formatting and providing syntax highlighting for Catspeak using a Prettier plugin.

Features

• Catspeak syntax highlighting!
• Pretty printing using Prettier's algorithm and mostly following Javascript formatting.
• Lovingly hand-written printing and ast-building logic.
• Comment support using Prettier's builtin plugin comment algorithm (it tries its best).
• Doesn't format files with syntax errors.
• Test cases!

Options

commaMode

Changes how commas are handled. normal prints non-trailing commas, trailing prints a trailing comma on wrapped lines, none attempts to remove all commas except those required to remove expression ambiguity. Default trailing.

-- commaMode = "normal"
[ a, b ]
[
  a,
  [b],
  long
]

-- commaMode = "trailing"
[ a, b ]
[
  a,
  [b],
  long,
]

-- commaMode = "none"
[ a b ]
[
  a,
  [b]
  long
]

printSemicolons

Changes how semicolons are handled. If enabled, each statement will be terminated with a semicolon. Default false.

-- printSemicolons = false
let foo = bar;
(baz)

-- printSemicolons = true
let foo = bar;
(baz);

emptyFunctionArguments

Determines if function declaration expressions with no arguments should have empty parenthesis. Default false.

-- emptyFunctionArguments = true
let fn = fun { }

-- emptyFunctionArguments = false
let fn = fun () { }

wrapBinaryOperators

If enabled, wrapped binary operation expressions will place their operator on a newline before the second operand. Default false.

-- wrapBinaryOperators = true
x = foo
    + bar

-- wrapBinaryOperators = false
x = foo +
    bar

parseCatchThrow

Version 3.2.0 of Catspeak introduces the throw and catch expressions and their keywords. When enabled, these keywords will be parsed as keywords instead of identifiers. Default true.

-- parseCatchThrow = true
let throw; -- errors
throw "hello"; -- formatted as an expression

-- parseCatchThrow = false
let throw; -- no error
throw; -- formatted as a identifier and a string
"hello";

indentAssignment

If enabled, assignment values that are a block statement (catch, do, if, match, while, with) will be indented. Default false.

-- indentAssignment = false
let x = do {
  long
}

-- indentAssignment = true
let x = do {
      long
    }