Get_started.adoc

Get Started

First example

• Create a directory called hello and create package.json as below:

  package.json

  {
      "dependencies": {
          "bs-platform": "0.9.3" // (1)
      },
      "scripts" : {
          "build" : "bsc -c  main_entry.ml"
      }
  }

  1. Version should be updated accordingly

• Create main_entry.ml as below:

  main_entry.ml

  let () =
    print_endline "hello world"

• Build the app

  npm run build

Now you should see a file called main_entry.js generated as below:

main_entry.js

// GENERATED CODE BY BUCKLESCRIPT VERSION 0.9.3 , PLEASE EDIT WITH CARE
'use strict';


console.log("hello world");

/*  Not a pure module */ (1)

1. The compiler analyze this module is impure due to the side effect

Tip	The working code is available here:

An example with multiple modules

Now we want to create two modules, one file called fib.ml which exports fib function, the other module called main_entry.ml which will call fib.

• Create a directory fib and created a file package.json

  package.json

  {
      "dependencies": {
          "bs-platform": "0.9.4"
      },
      "scripts" : {
          "build" : "bsc -c -bs-main main_entry.ml" // (1)
      }
  }

  1. here -bs-main option tells the compiler compile main_entry module and its dependency accordingly

• Create file fib.ml and file main_entry.ml

  fib.ml

  let  fib n  =
    let rec aux n a b =
      if n = 0 then a
      else
        aux (n - 1) b (a+b)
    in aux n 1 1

  main_entry.ml

  let () =
    for i = 0 to 10 do
      Js.log (Fib.fib i) (1)
    done

  1. Js module is a built-in module shipped with BuckleScript

• Build the app

  npm install
  npm run build
  node main_entry.js

If everything goes well, you should see the output as below:

1
1
2
3
5
8
13
21
34
55
89