display

The Display contract and show helper.

display defines the Display contract: a type that promises a to_text(): text method. Records with to_text can already be printed and formatted directly, but declaring with display.Display lets generic functions require that capability explicitly.

Use show when you want the rendered text value instead of printing immediately, especially inside generic code bounded by T is Display.

import display;

record Label with display.Display {
    name: text,

    fn to_text(): text {
        return format("label: {}", this.name);
    }
}

label = Label { name: "core" };
print(display.show(label));

Auto-generated from stdlib/display.dn by tools/gen_stdlib_docs.py.

fn show<T is Display>(value: T): text

Render any Display value to text. Useful when a function wants the text instead of printing it directly. The bound T is Display guarantees value has a to_text method to call.

Example:

display.show(Label { name: "core" })  // label: core