LiveScript

For the primary web scripting language initially known as LiveScript, see JavaScript.
LiveScript
Paradigm multi-paradigm, functional, object-oriented
Designed by Jeremy Ashkenas, Satoshi Murakami, George Zahariev
Developer Jeremy Ashkenas, Satoshi Murakami, George Zahariev
First appeared 2011 (2011)
Stable release
LiveScript 1.4.0 / 11 May 2015 (2015-05-11)[1]
Typing discipline dynamic, weak
OS Cross-platform
License MIT
Filename extensions .ls
Website livescript.net
Influenced by
JavaScript, Haskell, CoffeeScript, F#

LiveScript is a functional language that compiles to JavaScript. It was created by Jeremy Ashkenas—the creator of CoffeeScript—along with Satoshi Muramaki, George Zahariev, and many others.[2] Notably, LiveScript was briefly the name of JavaScript in 1990s.[3]

Syntax

LiveScript is an indirect descendant of and is partly compatible with Coffeescript.[4] The following is a fully Coffeescript-compatible hello-world example of LiveScript syntax.

hello = ->
  console.log 'hello, world!'

While calling a function can be done with empty parens, hello(), LiveScript treats the exclamation mark as a single-character shorthand for function calls with zero arguments: hello!

LiveScript introduces a number of other incompatible idioms:

Name mangling

At compile time, the LiveScript parser implicitly converts kebab case (dashed variables and function names) to camelcase.

hello-world = ->
  console.log 'Hello, World!'

With this definition, both the following calls are valid. However, calling using the same dashed syntax is recommended.

hello-world!
helloWorld!

This does not preclude developers from using camelcase explicitly or using snakecase. Dashed naming is however, common in idiomatic LiveScript[5]

Pipes

Like a number of other functional programming languages such as F# and Elixir, LiveScript supports the pipe operator, |> which passes the result of the expression on the left of the operator as the first argument to the expression on the right of it.

"hello!" |> capitalize |> console.log
# > Hello!

Operators as functions

When parenthesized, operators such as not or + can be included in pipelines or called as if they were functions.

111 |> (+) 222
# > 333

(+) 1 2
# > 3

References

  1. ↑ "LiveScript website". Retrieved 20 June 2015.
  2. ↑ "LiveScript contributors page". Retrieved 20 June 2015.
  3. ↑ "W3 Web Education Community Group". Retrieved 20 June 2015.
  4. ↑ http://livescript.net/
  5. ↑ http://www.preludels.com/


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