Function composition: Difference between revisions

=={{header|Transd}}==

<syntaxhighlight lang="Scheme">#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")))

}</syntaxhighlight>

{{out}}

<pre>

HELLO!

</pre>