Control flow and operators

These are the constructs you use inside a route or task to branch, loop, transform data, and compose values. The declarative keywords (route, schema, and so on) are in Keywords.

Conditionals

if / else works as a statement and as an expression that produces a value:

status = if cached
    cached
else
    "fresh"

Pattern matching

match tests a value against patterns, with fallback as the default branch:

label = match status
    "active" -> "on"
    fallback -> "off"

Loops

while repeats a block while its condition holds:

counter = 0
while counter < 3
    counter = counter + 1

Pipelines

>> passes the result of each step to the next, which reads left to right instead of nesting calls. It drives database queries, HTTP calls, and collection transforms:

recent = db.orders >> where(active: true) >> order_by("id desc") >> fetch

Broadcast

*>> sends the same value to several branches and collects their results positionally into a list. The runtime runs independent branches (outbound calls, separate queries) in parallel, so they overlap instead of waiting on each other:

sections = user_id *>>
    -> load_profile
    -> load_orders
    -> load_recommendations

See Broadcast for how the parallelism, result order, and the runtime’s optimization of trivial branches work.

Boolean operators

and, or, and not combine booleans. or also supplies a default when the left side is null or false:

name = user.name or "guest"
allowed = user.active and not user.banned

Collections

Transform a list with map, emitting values with keep and dropping elements with skip, and fold a list with reduce:

names = users >> map user
    skip if not user.active
    keep user.name

total = prices >> reduce(0) acc, item
    acc + item