Code blocks

run() evaluates a sequence of expressions in order, against a single shared context, and returns the value of the last one. Values stored by an earlier line with set() are visible to later lines.

$engine->run([
    'set("greeting", "Hello " + trigger.user.name)',
    'greeting.upper()',
], ['trigger' => ['user' => ['name' => 'Ada']]]);
// → "HELLO ADA"

This is the only place the language has anything like a variable.

set() and get()

set(key, value) writes a value into the shared context under key and returns that value. get(key) reads it back. Both take the key as an expression, so it's normally a string literal.

$engine->run([
    'set("subtotal", trigger.cart.items.map(current.price * current.qty).sum())',
    'set("tax", get("subtotal") * 0.15)',
    'get("subtotal") + get("tax")',
], $context);

Once a value has been set(), you can also read it as a plain path (subtotal), not just via get():

$engine->run([
    'set("total", trigger.a + trigger.b)',
    'total * 2',
], ['trigger' => ['a' => 3, 'b' => 4]]);
// → 14

set() / get() outside run()

set() and get() also work inside a single resolve() or evaluate() call, sharing context across the placeholders of one template string:

$engine->resolve(
    '{{ set("name", "Hello " + trigger.user.name) }}{{ get("name") }}',
    ['trigger' => ['user' => ['name' => 'Ada']]],
);
// → "Hello AdaHello Ada"

They are always available — they appear in availableFunctions() alongside the registered functions.

When to use run()

Reach for run() when a single expression would be unreadable because the same sub-result is needed several times, or when a calculation has natural intermediate steps (subtotal → tax → total). For anything that fits comfortably on one line, a plain evaluate() is simpler.