lambdas.md

Lambdas

Lambdas, or anonymous functions, are small functions created inside of another function. They have access to variables inside and parameters passed to that function. Budgie allows one-line lambdas to be passed in place of variables to other functions.

Lambda Types

To accept a lambda as a parameter, use the lambda type inline command to declare its type. It takes in the lambda's return type and zero to two (parameterName, parameterType) pairs.

You can then use the lambda command to call that lambda, which takes in the name of the lambda and any parameters to pass to it.

standalone function declare start : private RunOnInts void format { lambda type inline : string i int }
    for numbers start : i int 0 10
        print : { lambda : format i }
    for numbers end
standalone function declare end

C#:

private void RunOnInts(Func<int, void> format)
{
    for (int i = 0; i < 10; i += 1)
    {
        Console.WriteLine(format(i));
    }
}

Python:

def run_on_ints(format):
    for i in range(0, 10):
        print(format(i))

Lambda Declarations

New lambdas can be declared as parameters to called functions or other lambdas. Declare them with lambda declare, which takes in the return type of the lambda, zero to two (parameterName, parameterType) pairs, and the (single line) body of the lambda.

standalone function : private { main group } RunOnInts { lambda declare : string i int { string format : ("Int: {0}") i int } }

C#:

Program.RunOnInts((int i) => string.Format("Int: {0}", i));

Python:

run_on_ints((i) => print("Int: {0}".format(i)))