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Chapter 3: Advanced

Lesson 1: Registering users

Earlier, in the first chapter, we stored user names using variables. However, there might be thousands (or millions) of users for an application. We will need a better way to store those names, than the ones we discussed in the last chapter.

Before we move towards that objective, first let’s simply create a transition which will collect information from the user and allow them to register.

We have a task for you!

After the end of the previous transition, declare a new transition with the name register_user. You can currently leave the brackets after the transition name empty. Also, make sure to end the declaration of the transition with end keyword.

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scilla_version 0
import BoolUtils
library SocialMediaPayment
let one_msg = 
  fun (msg: Message) => 
  let nil_msg = Nil {Message} in
  Cons {Message} msg nil_msg
let zero = Uint128 0
let not_owner_code = Uint32 1
let accepted_code = Uint32 0
contract SocialMediaPayment (owner: ByStr20)
transition deposit()
  sender_is_owner = builtin eq _sender owner;
  match sender_is_owner with
  | False =>
    msg = { _tag: "";
            _recipient: _sender;
            _amount: zero;
            code: not_owner_code};
    msgs = one_msg msg;
    send msgs
  | True =>
    accept;
    msg = { _tag: "";
            _recipient: _sender;
            _amount: zero;
            code: accepted_code};
    msgs = one_msg msg;
    send msgs
  end
end
(* Start typing from the line below *)
transition register_user ()
end
scilla_version 0
import BoolUtils

library SocialMediaPayment

let one_msg = 
  fun (msg: Message) => 
  let nil_msg = Nil {Message} in
  Cons {Message} msg nil_msg

let zero = Uint128 0
let not_owner_code = Uint32 1
let accepted_code = Uint32 0


contract SocialMediaPayment (owner: ByStr20)

transition deposit()
  sender_is_owner = builtin eq _sender owner;
  match sender_is_owner with
  | False =>

    msg = { _tag: "";
            _recipient: _sender;
            _amount: zero;
            code: not_owner_code};
    msgs = one_msg msg;
    send msgs

  | True =>
    accept;
    msg = { _tag: "";
            _recipient: _sender;
            _amount: zero;
            code: accepted_code};
    msgs = one_msg msg;
    send msgs

  end
end

(* Start typing from the line below *)
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Chapter 3: Advanced

Lesson 2: Parameters for new users