Functions, types, enums and lists

Simple on top, a full language underneath.

AlgoBarsX

type Level:
price: price
touched: int = 0
formed_at: time
enum Regime: trending, ranging, volatile
fn swing_strength(len: int) -> number:
up = highest(high, len) - close
down = close - lowest(low, len)
return (down - up) / atr(14)
action fn enter_long(size_risk: percent = 1%) -> bool:
buy risk: size_risk, stop: 20 pips, target: 2R
return true

fn defines a pure function. It calculates and returns a value.
action fn may place orders, so it can only be called where orders are allowed. A plain fn that tries to trade is an error (AS0403).
type defines a record with named, typed fields and optional defaults. enum defines a fixed set of names.
Parameters can have types and defaults: fn f(source: series<number> = close, length: int = 20) -> number.

Lists and lambdas

AlgoBarsX

levels.push(Level(price: high, formed_at: time))
levels = levels.filter(l => l.touched == 0).keep_last(50)
ranked = levels.sort_by((a, b) => a.price - b.price)

Lists support push, pop, remove, filter, map, sort_by, keep_last, first, last, len and contains, plus the aggregates sum, mean, min and max. A lambda is written x => expression.