standard-libraries.md

Standard Libraries

When developing a realm in Gnolang, developers may utilize libraries in stdlibs. These are the core standard packages provided for Gnolang Realms & Packages.

Libraries can be imported in a manner similar to how libraries are imported in Golang.

An example of importing a std library in Gnolang is demonstrated in the following command:

import "std"

Let's explore some of the most commonly used modules in the library.

stdshim

banker.gno

A library for manipulating Coins. Interfaces that must be implemented when using this library are as follows:

// returns the list of coins owned by the address
GetCoins(addr Address) (dst Coins)

// sends coins from one address to another
SendCoins(from, to Address, amt Coins)

// returns the total supply of the coin
TotalCoin(denom string) int64

// issues coins to the address
IssueCoin(addr Address, denom string, amount int64)

// burns coins from the address
RemoveCoin(addr Address, denom string, amount int64)

coins.gno

A library that declares structs for expressing Coins. The struct looks like the following:

type Coin struct {
    Denom    string   `json:"denom"`     // the symbol of the coin
    Amount   int64    `json:"amount"`    // the quantity of the coin
}

testing

A library that declares *testing, which is a tool used for the creation and execution of test cases during the development and testing phase of realms utilizing the gno CLI tool with the test option.

There are 3 types of testing in gno.

• Type T
  • Type passed to Test functions to manage test state and support formatted test logs.
• Type B
  • Type passed to Benchmark functions.
    • Manage benchmark timing.
    • Specify the number of iterations to run.
• Type PB
  • Used by RunParallel for running parallel benchmarks.