lightscript

Functional JavaScript-compatible programming language

• Subset of ES3
• Import external JavaScript
• Type annotations

Type annotations

To keep ES3 compatibility, type annotations can be expressed as comments

//@: a -> a
var identity = function (value) {
  return value;
};

Type annotations will be applied to the next function expression found

Inline annotations are also valid

var api = {
  identity: /*@: a -> a */ function (value) {
    return value;
  }
};

References

• Ramda
• TypeScript
• JSON Schema
• Elm
• Haskell

Spec

Built-in objects

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects

• module

Expressions and operators

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators

Primary expressions

• function: function expression
• []: array initializer
• {}: object initializer
• (): grouping operator

Left-hand-side expressions

• object['property']: property accessors

Unary operators

• !: logical not

Arithmetic operators

• +: addition
• -: substraction
• *: multiplication
• /: division
• %: remainder

Relational operators

• <: less than
• >: greater than
• <=: less than or equal
• >=: greater than or equal

Equality operators

• ===: identity
• !==: non-identity

Binary logical operators

• &&: and
• ||: or

Assignment operators

• =: assignment

Statements and declarations

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements

Control flow

• {}: block
• if...else: executes a statement if expression is true
• throw: throws a user-defined exception
• try...catch: mark a block of statements to try

Declarations

• var: declares a variable, optionally initializing it to a value

Functions and classes

• return: specifies the value to be returned