Gleam language preview

1. Main with imports

import, pub fn, and types

horizon-dark

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

atom-one-dark

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

github-dark

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

dracula

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

nord

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

github

import gleam/io
import gleam/int

pub fn main() -> Nil {
  let total = add(2, 3)
  io.println("Sum: " <> int.to_string(total))
}

fn add(a: Int, b: Int) -> Int {
  a + b
}

2. Custom types and case

type definitions, constructors, and pattern matching

horizon-dark

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

atom-one-dark

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

github-dark

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

dracula

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

nord

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

github

pub type Shape {
  Circle(radius: Float)
  Square(side: Float)
}

pub fn area(shape: Shape) -> Float {
  case shape {
    Circle(r) -> 3.14 *. r *. r
    Square(s) -> s *. s
  }
}

3. Literals and externals

True/False/Nil, number bases, and @external

horizon-dark

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

atom-one-dark

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

github-dark

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

dracula

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

nord

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

github

const enabled = True
const mask = 0xFF
const flags = 0b1010

@external(erlang, "rand", "uniform")
pub fn random() -> Float

4. Pipe operator

|> threading a value through function calls

horizon-dark

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}

atom-one-dark

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}

github-dark

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}

dracula

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}

nord

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}

github

import gleam/int
import gleam/string

pub fn describe(n: Int) -> String {
  n
  |> int.to_string
  |> string.append("value: ", _)
}