Std.Tree.fold

fn

This is a callable function.

What it does

Every value combined into one, each node before its children.

The flat reading: the values arrive in preorder and the shape is gone. Use

foldTree where what a node answers depends on what its children answered.

Read the signature

• The text after the name is the type checked by Pudu.
• Read arrows from left to right: inputs come first, and the final type is returned.
• & borrows a value for this call instead of moving or copying it.
• Names inside [ ] are type arguments, such as the item type held by a collection.