#lang transd

MainModule: {
    // Make a short alias for a function type that takes a string and
    // returns a string. Call it 'Shader'.

    Shader: typealias(Lambda<String String>),

    // 'composer' function takes two Shaders, combines them into
    // a single Shader, which is a capturing closure, аnd returns
    // this closure to the caller.
    // [[f1,f2]] is a list of captured variables

	composer: (λ f1 Shader() f2 Shader()
        (ret Shader(λ[[f1,f2]] s String() (exec f1 (exec f2 s))))),

	_start: (λ
        // create a combined shader as a local variable 'render'

        locals: render (composer
            Shader(λ s String() (ret (toupper s)))
            Shader(λ s String() (ret (+ s "!"))))

        // call this combined shader as a usual shader with passing
        // a string to it, аnd receiving from it the combined result of
        // its two captured shaders

        (textout (exec render "hello")))
}