Chapter 2: Intermediate

Lesson 1: Making a transition for depositing tokens

In the last chapter, we learned about various kinds of variables, including implicit variable. Let’s build a transition that actually uses that. We’ll first wipe the variables from the first chapter, and from now onwards all the code that we’ll be using will help us directly build the social media payment application that we discussed.

First of all, in order to give ZIL tokens as rewards, the contract must have access to them. In order to ensure that, we need to build a transition where the ZIL tokens can be deposited in the contract.

We have a task for you!

Declare a transition with the name deposit. Make sure to close it with end keyword.

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Solution

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scilla_version 0
contract SocialMediaPayment (owner: ByStr20)
(* Start typing from the line below *)
transition deposit()
end

scilla_version 0

contract SocialMediaPayment (owner: ByStr20)
(* Start typing from the line below *)

Chapter 2: Intermediate

Lesson 2: Boolean operations

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Lesson 2: Boolean operations

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Cheat Sheet

Field Type	Field Type Keyword (Case Sensitive)	Mutable var declaration with Null value	Mutable var declaration with value	Declaration as a variable in transition	Declaration in the library
Signed Integer	`IntX` (Where X can be 32, 64, 128, or 256) `eg. Int32`	`field a: Option Int32 = None {Int32}`	`field a: Int32 = Int32 5`	`a = Int32 5`	`let a = Int32 5`
Unsigned Integer	`UintX` (Where X can be 32, 64, 128, or 256) `eg. Uint32`	`field a: Option Uint32 = None {Uint32}`	`field a: Uint32 = Uint32 5`	`a = Uint32 5`	`let a = Uint32 5`
String	`String`	`field a: String = ""`	`field a: String = "hello"`	`a = "hello"`	`let a = "xyz"`
Hash	`ByStr32`	`field a: Option ByStr32 = None {ByStr32}`	`field a: ByStr32 = 0x1234...0abff`	`a = 0x1234...0abff`	`let a = 0x1234...0abff`
Address	`ByStr20`	`field a: Option ByStr20 = None {ByStr20}`	`field a: ByStr20 = 0x1234...0abff`	`a = 0x1234...0abff`	`let a = 0x1234...0abff`
Block Number	`BNum`	`field a: Option BNum = None {BNum}`	`field a: BNum = BNum 5`	`a = BNum 5`	`let a = BNum 5`
Boolean	`Bool`	`field a: Option Bool = None {Bool}`	`field a: Bool = True`	`a = True`	`let a = True`
List	`List`	`field a: List(Int32) = Nil {Int32}`	`field a: List(Int32) = let b = Nil {Int32} in let c = Int32 5 in Cons {Int32} c b`	`a = Nil {Int32}`	`let a = Nil {Int32}`
Pair	`Pair (FieldType1) (Fieldtype2)`	`field a: Pair (String) (Option Uint32) = let b = "" in let c = None {Uint32} in Pair {(String) (Option Uint32)} b c`	`field a: Pair (String) (Uint32) = let b = "Hello" in let c = {Uint32} 5 in Pair {(String) (Uint32)} b c`	`a = let b = "Hello" in let c = {Uint32} 5 in Pair {(String) (Uint32)} b c`	`let a = let b= "Hello" in let c = {Uint32} 5 in Pair {(String) (Uint32)} b c`
Map	`Map FieldType1(Key) FieldType2(Value)` Keys can have the following types: `IntX` `UintX` `String` `ByStr32` `ByStr20` Values can be of any type.	`field a: Map FieldType1 FieldType2 = Emp FieldType1 FieldType2`	`field a: Map ByStr20 String = let b = Emp ByStr20 String in let c = 0x1234...0abff in let d = ""Hello"" in builtin put b c d "`	`a = let b = Emp ByStr20 String in let c = 0x1234...0abff in let d = ""Hello"" in builtin put b c d "`	`let a = let b = Emp ByStr20 String in let c = 0x1234...0abff in let d = ""Hello"" in builtin put b c d "`