Files
yamlabyrinth/src/levels/l05_dict_list.rs
2026-05-21 23:15:50 +03:00

121 lines
3.6 KiB
Rust

//! Level 5 — dictionaries AND lists. Each chamber keeps its own inventory.
//!
//! Paired design note: `l05.md`.
use rand::seq::SliceRandom;
use rand::{Rng, SeedableRng};
use rand_chacha::ChaCha8Rng;
use serde::Serialize;
use serde_yaml::{Mapping, Sequence, Value};
use crate::describe::Describer;
use super::{Generated, Level};
pub struct DictList;
const CHAMBERS: &[&str] = &[
"armory", "pantry", "library", "vault", "kitchen", "cellar",
];
const ITEMS: &[&str] = &[
"sword", "shield", "bread", "water", "tome", "scroll", "gem", "coin", "dagger", "potion",
];
#[derive(Serialize)]
struct DescCtx {
sentences: Vec<String>,
}
/// Pick "a" or "an" based on the first letter — keeps the prose reading
/// naturally without giving away that chamber names are YAML keys.
fn article(word: &str) -> &'static str {
let first = word.chars().next().map(|c| c.to_ascii_lowercase());
if matches!(first, Some('a') | Some('e') | Some('i') | Some('o') | Some('u')) {
"an"
} else {
"a"
}
}
/// Join the item list as English: `a sword`, `a sword and a shield`,
/// `a sword, a shield, and a potion` (Oxford comma for 3+).
fn join_items(items: &[&str]) -> String {
let parts: Vec<String> = items
.iter()
.map(|i| format!("{} {}", article(i), i))
.collect();
match parts.as_slice() {
[] => String::new(),
[one] => one.clone(),
[a, b] => format!("{a} and {b}"),
rest => {
let (last, head) = rest.split_last().unwrap();
format!("{}, and {}", head.join(", "), last)
}
}
}
impl Level for DictList {
fn id(&self) -> u8 {
5
}
fn name(&self) -> &'static str {
"Chambers"
}
fn generate(&self, seed: u64) -> Generated {
let mut rng = ChaCha8Rng::seed_from_u64(seed ^ 0x0000_0000_0000_0005);
let n = rng.gen_range(2..=3);
let chamber_names: Vec<&'static str> =
CHAMBERS.choose_multiple(&mut rng, n).copied().collect();
let mut inner = Mapping::new();
let mut sentences = Vec::new();
for name in &chamber_names {
let item_n = rng.gen_range(2..=3);
let items: Vec<&'static str> =
ITEMS.choose_multiple(&mut rng, item_n).copied().collect();
let seq: Sequence = items
.iter()
.map(|i| Value::String((*i).to_string()))
.collect();
inner.insert(Value::String((*name).to_string()), Value::Sequence(seq));
let be = if items.len() == 1 { "is" } else { "are" };
sentences.push(format!(
"There {be} {} inside {} {name}.",
join_items(&items),
article(name),
));
}
let mut top = Mapping::new();
top.insert(
Value::String("chambers".to_string()),
Value::Mapping(inner),
);
let target_yaml =
serde_yaml::to_string(&Value::Mapping(top)).expect("serialise mapping");
let mut d = Describer::new();
d.register(
"l05",
"Several chambers branch off, each with its own contents:\n\
{% for s in sentences %}\n {{ s }}{% endfor %}\n\n\
💡 Wrap the whole tree under a `chambers:` key — a dict of lists.",
)
.expect("register template");
let description = d
.render("l05", &DescCtx { sentences })
.expect("render template");
Generated {
target_yaml,
description,
flavor: "🏛 You enter a hall. Doors lead to many chambers.".to_string(),
}
}
}