7. Call arguments

Canonical source: protos/tutorials/07-call-arguments/ at locked revision e99b712ecf658a527b1fe82c8beba2c1286d8dc9.

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01 — Defaults args and rest

Canonical source protos/tutorials/07-call-arguments/01-defaults-args-and-rest.protos

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// Calls evaluate their supplied positional arguments before parameter binding.
// A default can read an earlier parameter from the real invocation activation.
next: (value, fallback = value + 1) => {
    Array(value, fallback)
}

defaulted: next(41)
explicit: next(10, 99)

// A rest parameter receives only the unconsumed supplied suffix. The spelling
// `args` below is an ordinary rest-parameter name, not an ambient call binding.
collect: (head = 1, ...args) => {
    Array(head, args.size())
}

rested: collect(10, 20, 30)

Array(defaulted, explicit, rested)

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