Functions

In OSL, you can define custom functions to modularize and reuse your code. Functions can take multiple parameters, perform operations, and return results. These functions can be invoked with specific arguments and used throughout your script.

Defining a Custom Function

To define a custom function, use the def keyword followed by the function name and parameters. Inside the function, use this to ensure variables are local to the function context.

Example: Basic Arithmetic Function

Here’s how you can create a function that performs basic arithmetic operations and returns a result:

def calculate(this.num1, this.num2, this.operation) (
  switch this.operation (
    case "add"
      this.result = this.num1 + this.num2
      break
    case "subtract"
      this.result = this.num1 - this.num2
      break
    case "multiply"
      this.result = this.num1 * this.num2
      break
    case "divide"
      this.result = this.num1 / this.num2
      break
  )
  return this.result
)

log calculate(10,5,"add")
// Outputs: 15
log calculate(10,5,"subtract")
// Outputs: 5
log calculate(10,5,"multiply")
// Outputs: 50
log calculate(10,5,"divide")
// Outputs: 2

Example: String Manipulation Function

You can also define functions to perform operations on strings. Here’s an example of a function that reverses a string:

def reverseString(this.text) (
  this.reversed = ""
  i = this.text.len
  loop this.text.len (
    this.reversed += this.text[i]
    i --
  )
  return this.reversed
)

log reverseString("hello")  // Outputs: "olleh"

Example: Combining Functions and Events

You can define a function and then trigger it based on an event. Here’s an example where a function is called when a specific key is pressed:

def greet(this.name) (
  this.message = "Hello," + this.name ++ "!"
  return this.message
)

if "G".onKeyDown() (
  say greet("Alice")  // Outputs: "Hello, Alice!"
)

Example: Complex Data Processing

Custom functions can also handle complex data processing, such as filtering an array:

def filterEvenNumbers(this.nums) (
  this.even = []
  for i this.nums.len (
    if this.nums[i] % 2 == 0 (
      this.even = this.even.append(this.nums[i])
    )
  )
  return this.even
)

data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
log filterEvenNumbers(data)  // Outputs: [2, 4, 6, 8, 10]