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LiveScript (programming language)

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LiveScript
Paradigmmulti-paradigm, functional, object-oriented
Designed byJeremy Ashkenas, Satoshi Murakami, George Zahariev
DeveloperJeremy Ashkenas, Satoshi Murakami, George Zahariev
First appeared2011; 13 years ago (2011)
Stable release
LiveScript 1.6.1 / 14 July 2020; 3 years ago (2020-07-14)[1]
Typing disciplinedynamic, weak
OSCross-platform
LicenseMIT
Filename extensions.ls
Websitelivescript.net
Influenced by
JavaScript, Haskell, CoffeeScript, F#

LiveScript is a functional programming language that transpiles to JavaScript. It was created by Jeremy Ashkenas—the creator of CoffeeScript—along with Satoshi Muramaki, George Zahariev, and many others.[2] (The name may be an homage to the beta name of JavaScript; for a few months in 1995, it was called LiveScript before the official release.[3])

Syntax[edit]

LiveScript is an indirect descendant of CoffeeScript.[4] The following "Hello, World!" program is written in LiveScript, but is also compatible with Coffeescript:

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[edit]

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

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 camel case explicitly or using snake case. Dashed naming is however, common in idiomatic LiveScript[5]

Pipes[edit]

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 an argument to the expression on the right of it. Note that in F# the argument passed is the last argument, while in Elixir it is the first.

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

Operators as functions[edit]

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[edit]

  1. ^ "LiveScript Releases". GitHub. Retrieved 21 February 2021.
  2. ^ "LiveScript contributors page". GitHub. Retrieved 20 June 2015.
  3. ^ "Chapter 4. How JavaScript Was Created". speakingjs.com. Archived from the original on 2020-02-27. Retrieved 2017-11-21.
  4. ^ "LiveScript - a language which compiles to JavaScript".
  5. ^ "prelude.ls - a functionally oriented utility library in LiveScript".

External links[edit]