vyper-cheatsheet

Motivation

This document is a cheatsheet for Vyper that you can use to write Smart Contracts for Ethereum.

This guide is not intended to teach you Vyper from the ground up, but to help developers with basic knowledge who may struggle to get familiar with Smart Contracts and Blockchain because of the Vyper concepts used.

Note: Vyper is very similar to Python and if you have basic knowledge in Python, it's easier to learn Vyper.

Table of contents

[WIP]

Types

Integer

Unsigned : uint256

Signed : int128

Operators

• Comparison: <, >, <=, >=, ==, !=
• Arithmetic: +, -, unary -, *, /, **, %, min(), max()
• Bitwise: bitwise_and(), bitwise_not(), bitwise_or(), bitwise_xor(), shift()

In shift(a, _shift) _shift must be of the type int128, where positive _shift means a left shift and negative _shift means a right shift.

Decimels

decimal: Holds a decimal fixed point value.

Operators

• Comparison: <, >, <=, >=, ==, !=
• Arithmetic: +, -, unary -, *, /, **, %

Address

address: Holds an Ethereum address (20 byte value).

Members

• balance: Get balance of the address in wei_value.
• codesize: Get code stored at this address. Returns int128.

Time

timestamp: Holds the time

timedelta: Time difference

Two timedelta or a timedelta and a timestamp can be added together . It is not possible to add two timestamp values.

wei_value

wei_value: Holds amount of Ether in its smallest denomination.

Boolean

bool: true or false

Operators: not, and, or, ==, !=

Structs

User defined data type.

<struct_name>: {
    <value>: <data_type>,
    <value>: <data_type>,
    ...
}

Mappings

Mappings are similar to hash tables.

<mapping_name>: <value_type>[<key_type>]

Functions

Structure

def <function_name>(<param_name>: <param_type>, ...) -> <return_type>:
    <definition>
    ...

Constructor

Function which is called during contract creation

def __init__(_a: address, _b: bool):
  self.a = _a;
  self.b = _b