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A folder's `mod.hd` lists what the folder offers, and another package is one more root

A folder of files becomes a module when it holds a mod.hd: src/shop/ is shop, and src/shop/cart.hd is shop.cart. The mod.hd is the folder's index. Its pub use lines name what pkg.shop offers, so the rest of the package imports from the folder, not from whichever file a name lives in today. A name it does not list is not part of pkg.shop, even when it is pub in cart.hd. Another package works the same way under one more root: after hd add ../money, its public names are dep.money. Open the shop/mod.hd and shop/cart.hd tabs to see the folder.

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use pkg.shop.{Line, total} # ← from the folder, as its mod.hd lists thempub fn main() -> void $ Console: cart := [Line { item: "lamp", cents: 3200 }, Line { item: "bulb", cents: 450 }] println("total: ${total(cart)} cents")# mod.hd does not list `shipping`. Ask for it anyway: change the# first line to `use pkg.shop.{Line, total, shipping}` and Run:# unknown-import: module 'playground.shop' declares no 'shipping'

pub struct Line: pub item: string pub cents: i32pub fn total(lines: List[Line]) -> i32: lines.iter().fold(0, fn(sum: i32, line: Line) -> i32: sum + line.cents) + shipping(lines)# Public, but mod.hd does not list it, so pkg.shop does not offer it.pub fn shipping(lines: List[Line]) -> i32: if lines.len() >= 3: 0 else: 499

A folder's mod.hd lists what the folder offers, and another package is one more root

A folder's `mod.hd` lists what the folder offers, and another package is one more root