The option-map door: a key nothing reads is refused, and so is an opts that is not
a map.
Nearly every public entry point that takes trailing options wants exactly this, and
wants it for one reason: an option nothing reads takes the default in silence.
That is the quietest failure the API has — {:max-derivation 5} for :max-derivations
reads as no bound at all and the chain runs unbounded, {:strengh :monotonic} stores a
default where known-true was meant, {:varient :index} writes a dump other than the one
asked for. Each returns a handle, a count, a summary that looks exactly right.
So the shape was written out at nine doors, identically bar the noun and one sentence,
and this is that shape once. What a caller supplies is the key set, the subject the
message names, and the consequence — the clause saying what taking the default
silently would have cost here, which is the sentence worth writing per door and the
only part of the refusal that ever carried information the others did not.
A door with further checks on the values of known keys keeps them; this is the key check, and it runs first because a misspelt key is not a bad value — it is a key that is not there.
The option-map door: a key nothing reads is refused, and so is an `opts` that is not
a map.
Nearly every public entry point that takes trailing options wants exactly this, and
wants it for one reason: **an option nothing reads takes the default in silence.**
That is the quietest failure the API has — `{:max-derivation 5}` for `:max-derivations`
reads as no bound at all and the chain runs unbounded, `{:strengh :monotonic}` stores a
default where known-true was meant, `{:varient :index}` writes a dump other than the one
asked for. Each returns a handle, a count, a summary that looks exactly right.
So the shape was written out at nine doors, identically bar the noun and one sentence,
and this is that shape once. What a caller supplies is the key set, the `subject` the
message names, and the `consequence` — the clause saying what taking the default
silently would have cost *here*, which is the sentence worth writing per door and the
only part of the refusal that ever carried information the others did not.
A door with further checks on the *values* of known keys keeps them; this is the key
check, and it runs first because a misspelt key is not a bad value — it is a key that
is not there.(check! opts opt-keys subject)(check! opts opt-keys subject consequence)Refuse a non-nil non-map opts, and any key outside opt-keys — :unknown-option
both, carrying :options (the roster) and, for the second, :unknown (what was
passed). subject names the door in the message; consequence is the clause on what
the silent default would have done, and may be nil where the roster speaks for itself.
opt-keys is a set, used as the membership predicate and sorted for the message.
The second map? is redundant to a reader and load-bearing to clj-kondo, which does
not narrow a type through a when whose body throws: a bare (keys opts) below tells
it opts is seqable, and it propagates that up through every caller to
vaelii.core/assert's own signature — where the suite's deliberate :nope becomes a
type error. The guard is the narrowing, so keep it.
Refuse a non-nil non-map `opts`, and any key outside `opt-keys` — `:unknown-option` both, carrying `:options` (the roster) and, for the second, `:unknown` (what was passed). `subject` names the door in the message; `consequence` is the clause on what the silent default would have done, and may be nil where the roster speaks for itself. `opt-keys` is a set, used as the membership predicate and sorted for the message. The second `map?` is redundant to a reader and load-bearing to clj-kondo, which does not narrow a type through a `when` whose body throws: a bare `(keys opts)` below tells it `opts` is seqable, and it propagates that up through every caller to `vaelii.core/assert`'s own signature — where the suite's deliberate `:nope` becomes a type error. The guard is the narrowing, so keep it.
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