Top-Level Definitions

• Do not indent the top level definitions.

Do’s

import ballerina/http;

const int MIN_AGE = 20;
int repetitions = 0;
    
service hello 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 hello on ep1 {
    ...
    }
        

• Imports
• Function Definition
• Service Definition
• Object Definition
• Record Definition
• Referencing Record or Abstract Object

Imports

• 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 has an object attached to it, do not keep spaces around the Dot .. Also, keep a single space between the function keyword and the name of the object.

Example,

function Person.getName() {}

• If the function needs to be split in to new lines due to it exceeding the max line length,
  • can break lines from the parameter list by moving a parameter value only 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 | ()) {
    ...
}

• 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 | ()) {
    ...
}    

• 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 hello on new http:Listener(9090) {
  ...
}

• When formatting resource functions and function definitions, block indent each element and follow the function formatting guidelines.

Example,

service hello on ep1, ep2 {
    resource function sayHello(http:Caller caller, http:Request req) returns error? {
        http:Response res = new;
        res.setPayload(self.getGreeting());
        _ = caller->respond(res);
    }
        
    function getGreeting() returns string {
        return "Hello";
    }
}

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

Object definition

• Block indent each field definition and each function definition on their own line.
• Init function should be placed before all the other functions.
• For function definitions in the object definition, follow the function formatting guidelines.

Example,

type Person object {
    // Object field definitions.
    public boolean isMarried = false;
      int age;
      string name;
  
    // Object init function.
    function __init(string name, int age = 0) {
        self.age = age;
        self.name = name;
    }
  
    // Object function definitions.
    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;
|}

Referencing record or abstract object

• Do not keep spaces between the *, the abstract 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 abstract object {
    string name;
  
    // Object function definitions.
    function getName() returns string;
};

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

    function __init() {
          self.name = "asd";
      }

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