@redshift/core v0.7.0

Redshift - functional programming language

Redshift is a functional programming language compiled to Javascript. It implements syntax similiar to Elixir. It is created as a part of learning how do compilers work, and it's mostly just proof of concept.

Key concepts

• no mutations
• no classes, no this
• all functions must return

Getting Started

Installation

Install compiler via npm:

npm install -g @redshift/cli

Generating project files

Redshift provides CLI that helps with scaffolding code.

redshift create <project_name>
cd <project_name>

Once generated you can use npm scripts to run your application.

REPL mode

redshift repl

One time build

redshift build <path_to_file>.rh

Watching for changes

redshift watch <path_to_file>.rh

Both options accept optional output argument (it defaults to ./bin/bundle.js):

redshift build path/to/file.red -o dist/directory/build.js

Syntax

Function declaration

Functions are defined by use of def/do/end keywords. The last expression will be returned.

def sum(a, b) do
  a + b
end

Function expressions

Redshift lets you define function expressions by using -> syntax. Expression after arrow will be returned.

To call anonymous function, dot syntax is used. This indicates that called function is an anonymous function and pattern matching should not be performed.

let double = (a) -> a * 2

double.(2) # 4

let greeted = List.map(names, (name) -> "Hello " <> name <> "!")

Constants

Because of lack of mutations, redshift supports constants only. Constants are block scoped.

let test_constant = 2
let result = 2 * 3

Constants can also be used inside functions

let a = 5

def func() do
  let a = 40
  let b = 100

  a + b
end

a # 5

Imports

There are three types of imports.

System Imports

Load built-in libraries like Math or IO

import Math
import IO

Node Modules Imports

Load javascript module from node_modules directory

import "lodash" as _
import "ramda" as R

Internal file imports

Load modules from another files (either .rh or .js) File extension is required.

import "./lib/Auth.rh" as Auth
import "./js/User.js" as User

String literals

String literals are declared using double quotes ".

let hello_world = "Hello world!"

To concat two strings use concatenation operator <>.

let str1 = "Hello "
let str2 = "world!"

let result = str1 <> str2

List Literals

Lists are declared using square parentheses [].

let names = ["tom", "mark", "andrew"]

To concat two lists use concatenation operator ++.

let names = ["tom", "mark", "adam"]
let other_names = ["anna", "kasia", "ewelina"]

let all = names ++ other_names

To perform more advanced operations like mapping, reducing, filtering and searching use List module

import List

let numbers = [1, 2, 3]
let double = (num) -> num * 2

let doubled = List.map(numbers, double)

## Head | Tail
let head = List.head(numbers) # 1
let tail = List.tail(numbers) # [2, 3]