Langlib Functions

This is a library which provides fundamentnal operations on built-in datatypes. There is a ballerina/lang.T module for each built-in type T and they are automatically imported using T prefix.

We can call Langlib functions in two ways and both produce the same result.

Currently there is Langlib module for following built-in types.

For Simple Types - lang.boolean, lang.int, lang.float, lang.decimal
For Structured Types - lang.array, lang.map, lang.table
For Sequence Types - lang.string, lang.xml
For Behavioral Types - lang.object, lang.error, lang.stream, lang.future, lang.typedesc
For common types, provides functions that work on values of more than one basic type - lang.value

Other than above modules for built-in types Langlib has following modules as well.

For functions related to language runtime - lang.runtime
For functions related to transactions - lang.transaction

Langlib functions can be called in two different ways.

Using method call syntax

import ballerina/io;

public function main() {
    // Can call using the conventinent method-call syntax.
    string s = "hello World".substring(1, 2);

    io:println(s);
}

Using as a module function

import ballerina/io;

public function main() {
    // Can call as a langlib module function. No need to import explicitly. 
    string s = string:substring("Hello World", 1, 2);

    io:println(s);
}