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import gleam/bool
import gleam/list
import gleam/set.{type Set}
import ext/setx
pub opaque type Hex {
Hex(q: Int, r: Int, s: Int)
}
pub const zero = Hex(q: 0, r: 0, s: 0)
pub const e = Hex(q: 1, r: 0, s: -1)
pub const se = Hex(q: 0, r: 1, s: -1)
pub const sw = Hex(q: -1, r: 1, s: 0)
pub const w = Hex(q: -1, r: 0, s: 1)
pub const nw = Hex(q: 0, r: -1, s: 1)
pub const ne = Hex(q: 1, r: -1, s: 0)
pub fn add(a: Hex, b: Hex) -> Hex {
Hex(q: a.q + b.q, r: a.r + b.r, s: a.s + b.s)
}
fn directions7() -> Set(Hex) {
set.from_list({
use q <- list.flat_map([-1, 0, 1])
use r <- list.flat_map([-1, 0, 1])
use s <- list.flat_map([-1, 0, 1])
use <- bool.guard(when: q + r + s != 0, return: [])
[Hex(q, r, s)]
})
}
fn directions6() -> Set(Hex) {
set.delete(from: directions7(), this: zero)
}
pub fn neighbours6(h: Hex) -> Set(Hex) {
setx.map(directions6(), with: add(h, _))
}
pub fn neighbours7(h: Hex) -> Set(Hex) {
setx.map(directions7(), with: add(h, _))
}
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