General practices

• Do not indent the top-level definitions.

Do's

import ballerina/http;

const int MIN_AGE = 20;
int repetitions = 0;

service / on ep1 {
    ...
}

Don'ts

// This import is indented correctly.
import ballerina/http; 
    
    const int MIN_AGE = 20; // Not indented correctly.
    int repetitions = 0; // Not indented correctly.
        
// Not indented correctly.
service / on ep1 {
    ...
    }

Import declaration

• Do not keep spaces between the organization name, divider /, and module name.

Example,

import ballerina/http;

• Imports should be sorted alphabetically, first by the organization name and then by the module name.

Function definition

• Do not keep spaces between the function name and the open parentheses ( of the function signature.

Example,

function func1() {
}

• If the function needs to be split into new lines due to it exceeding the max line length, you can break lines from the parameter list by moving only a parameter value to a new line and indenting it with four spaces from the starting position of the function.

Example,

function getAddress(int value,
    string name) returns string? {
    ...
}

• You can break before the returns keyword and indent it with four spaces from the starting position of the function.

Example,

function getAddress(int value, string name)
    returns string? {
    ...
}

• You can break after the returns keyword by moving the return value to a new line and indenting it with four spaces from the starting position of the function.

Example,

function getAddress(int value, string name) returns
    string? {
    ...
}

Service definition

• Keep the listener inline with the service signature.

Example,

service / on new http:Listener(9090) {
  ...
}

• When formatting service-level method definitions, block indent each element and follow the Function definition formatting guidelines.

Example,

import ballerina/http;

service / on new http:Listener(9090) {

    resource function get greeting() returns string {
        return "Hello, World!";
    }
    
}

• Block indent each method definition, and field definition inside a service definition.

Class definition

• Block indent each field definition, method definition and type inclusion on their own line.
• The init method should be placed before all the other methods.
• For method definitions in the class definition, follow the Function definition formatting guidelines.

Example,

class Person {
    public boolean isMarried = false;
    int age;
    string name;

    function init(string name, int age = 0) {
        self.age = age;
        self.name = name;
    }

    function getName() returns string {
        return self.name;
    }

    function setIsMarried(boolean isMarried) {
        self.isMarried = isMarried;
    }

    function getIsMarried() returns boolean {
        return self.isMarried;
    }
}

Record definition

Block indent each of the field definitions (including the rest field) in their own line.

Example,

type Person record {|
    string name;
    int...;
|};

// or

type Person record {|
    int id;
    string name;
|};

Reference record or object

• Do not keep spaces between the * and the object name or the record name.

Example,

*Person;

• Also, block-indent.

Example:

type UserId record {
    string id = "";
};
  
type User record {
    *UserId; // Reference to UserId record.
    string name = "john";
    int age = 20;
};

// or
type Person object {
    string name;

    // Object function definitions.
    function getName() returns string;
};

class Employee {
    *Person; // Reference to Person object type.

    function init() {
        self.name = "John Doe";
    }

    function getName() returns string {
        return self.name;
    }
}