Read-WRITE Traversal over JSON byte buffers. Resolves a wildcard-bearing JSONPath against Array[Byte], decodes each matched span via JsonValueCodec[A] on read, and encodes-and- splices every focus back in one pass on write. No runtime AST.
Carrier: MultiFocus[PSVec] — the same carrier Traversal.each uses, peer to all the classical Traversal idioms. The choice over MultiFocus[List] matters for downstream composition: JsoniterTraversal[A].andThen(Traversal.each[List, A]) and similar same-carrier chains work via the existing mfAssocPSVec AssociativeFunctor instance, with zero-copy per-element reassembly. A List-carrier traversal would force a Composer hop or a manual .modify rebuild.
type X = (Array[Byte], List[JsonPathScanner.Span])— original bytes + each KEPT focus's span, 1:1 aligned with the foci (spans whose decode throws are dropped TOGETHER with their focus, so the write side can trust the pairing).to: Array[Byte] => (X, PSVec[A])— runs JsonPathScanner.findAll, decodes every span via the codec into a singleArray[Any]allocation, wraps it as a PSVec. Spans whose decode throws are silently dropped (matches the read semantic "fold the focuses that exist") — and stay byte-untouched on write.from: ((X, PSVec[A])) => Array[Byte]— encodes each focus viawriteToArrayand splices all spans back in a single pass (segments between spans arearraycopyd verbatim). A span↔foci length mismatch (an aggregatefromafter a shape-changing carrier op) passes the original bytes through unchanged, as does an empty focus set.
Composability: standard cats-eo extensions on Optic[..., MultiFocus[PSVec]] light up automatically via mfFold[PSVec], mfFunctor[PSVec], mfAssocPSVec, etc. — .foldMap, .modify, .headOption, .length, .exists, .modifyA, same-carrier .andThen all work without anything new shipping in this module. Mirrors dev.constructive.eo.avro.AvroTraversal's byte-carried write semantics. JsoniterPrism's '''Laws & preconditions''' apply verbatim: laws hold up to canonical re-encoding of the focused slices, and writes need decodable current focuses.
Typed drilling continues past the wildcard, mirroring eo-circe's JsonTraversal: JsoniterPrism[Basket].field(_.items).each.field(_.price) focuses price of every element. Each step is compile-time checked against the case-class schema and appends to the path.
Attributes
- Companion
- object
- Source
- JsoniterTraversal.scala
- Graph
-
- Supertypes
-
trait Dynamicclass Objecttrait Matchableclass AnyShow all
Members list
Grouped members
Operations
Build-then-observe across the build-output ⇄ read-input seam, preserving structure, on a shared carrier F. Flip self (it must be reversible — Accessor[F] and ReverseAccessor[F], i.e. an Iso or Review over Direct) so it reads T from B, then andThen that under the same carrier. The result is the full Optic[B, A, C, D, F], not a collapsed getter: its read capability follows the carrier (.get for Direct), and self's read focus A survives as the composite's write-back focus.
Build-then-observe across the build-output ⇄ read-input seam, preserving structure, on a shared carrier F. Flip self (it must be reversible — Accessor[F] and ReverseAccessor[F], i.e. an Iso or Review over Direct) so it reads T from B, then andThen that under the same carrier. The result is the full Optic[B, A, C, D, F], not a collapsed getter: its read capability follows the carrier (.get for Direct), and self's read focus A survives as the composite's write-back focus.
This is exactly self.reverse.andThen(that). The motivating case is ana.cross(cata): a Review (the unfold) crossed with a getter on the built S (the fold) — a (materializing) hylomorphism whose .get reads the folded value. When that sits on a different carrier (a Prism, a Fold, …), the cross-carrier cross overload below is selected instead.
Seam: that's source is self's T and its back-type is self's S.
Attributes
- Inherited from:
- Optic
- Source
- Optic.scala
Type members
Types
Existential leftover carried alongside the focus — the type-level witness the carrier uses to rebuild T. Concrete at construction (Lens.apply sets X = S, Prism.apply sets X = S, …) and abstract when the optic is bound to Optic[…, F] without refinement.
Existential leftover carried alongside the focus — the type-level witness the carrier uses to rebuild T. Concrete at construction (Lens.apply sets X = S, Prism.apply sets X = S, …) and abstract when the optic is bound to Optic[…, F] without refinement.
Attributes
- Source
- JsoniterTraversal.scala
Value members
Concrete methods
.at(i) — drill every focus into the i-th element of a nested array.
.at(i) — drill every focus into the i-th element of a nested array.
Attributes
- Source
- JsoniterTraversal.scala
.field(_.x) — drill every focus into a field, compile-time checked against A.
.field(_.x) — drill every focus into a field, compile-time checked against A.
Attributes
- Source
- JsoniterTraversal.scala
Close the carrier: given a modified focus B (and the leftover X already inside the F), reassemble the result T.
Close the carrier: given a modified focus B (and the leftover X already inside the F), reassemble the result T.
Attributes
- Source
- JsoniterTraversal.scala
Dynamic field sugar — itemsT.price lowers to itemsT.field(_.price).
Dynamic field sugar — itemsT.price lowers to itemsT.field(_.price).
Attributes
- Source
- JsoniterTraversal.scala
Push the source S into the carrier, extracting the focus A and packing the leftover X. Paired with from to reconstruct T.
Push the source S into the carrier, extracting the focus A and packing the leftover X. Paired with from to reconstruct T.
Attributes
- Source
- JsoniterTraversal.scala
Inherited methods
Fused Traversal.andThen(Lens) — SplitCombineLens / SimpleLens (macro-lens) inner.
Fused Traversal.andThen(Lens) — SplitCombineLens / SimpleLens (macro-lens) inner.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
Fused Traversal.andThen(Lens) — lifts the lens through the same tuple2multifocusPSVec bridge the Morph-routed generic extension uses, then composes on the shared carrier. See the andThen(inner: Traversal) overload for why the concrete return type matters.
Fused Traversal.andThen(Lens) — lifts the lens through the same tuple2multifocusPSVec bridge the Morph-routed generic extension uses, then composes on the shared carrier. See the andThen(inner: Traversal) overload for why the concrete return type matters.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
Fused same-carrier Traversal.andThen(Traversal) — same composition as the generic Optic.andThen (the mfAssocPSVec kernel), re-homed under the concrete Traversal class via Traversal.composed. The generic member returns an anonymous Optic, so a composed chain's .modify / .foldMap resolve to the generic extensions — which re-instantiate the parameterized mfFunctor[PSVec] / mfFold[PSVec] givens per call (the measured 40 B/op of the class scaladoc) and share one megamorphic body. Returning Traversal keeps the fused inline members (and per-site monomorphic to / from dispatch) on every chain.
Fused same-carrier Traversal.andThen(Traversal) — same composition as the generic Optic.andThen (the mfAssocPSVec kernel), re-homed under the concrete Traversal class via Traversal.composed. The generic member returns an anonymous Optic, so a composed chain's .modify / .foldMap resolve to the generic extensions — which re-instantiate the parameterized mfFunctor[PSVec] / mfFold[PSVec] givens per call (the measured 40 B/op of the class scaladoc) and share one megamorphic body. Returning Traversal keeps the fused inline members (and per-site monomorphic to / from dispatch) on every chain.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
ANY outer ∘ read-only inner — the inner is honestly one-way (T = Unit: a Getter, AffineFold, or Fold), so only the two READ sides matter and the composite collapses to the read-only join of their strengths via compose.ReadCompose (Getter / PickFold / ForgetFold).
ANY outer ∘ read-only inner — the inner is honestly one-way (T = Unit: a Getter, AffineFold, or Fold), so only the two READ sides matter and the composite collapses to the read-only join of their strengths via compose.ReadCompose (Getter / PickFold / ForgetFold).
A trait member (not an extension in the companion) deliberately: once a receiver is statically one of the fused concrete classes, its andThen member overloads enter resolution and Scala 3 never falls back to extension methods when they all fail — the collapse must be in the member overload set to be reachable without an expected-type ascription.
Only the inner's T is pinned to Unit; its B stays free (IB) even though read-only inners always have B = Unit. That keeps this overload strictly LESS specific than the same-carrier andThen above (which accepts every argument this one does whenever B = Unit at the receiver), so a same-carrier read-only ∘ read-only call resolves unambiguously to the AssociativeFunctor path and this one fires exactly on the cross-seam cells the generic member cannot type.
Attributes
- Inherited from:
- Optic
- Source
- Optic.scala
Compose with another optic under the shared carrier F. Requires AssociativeFunctor[F]. Cross-carrier composition (Lens → Optional, Lens → Traversal, …) goes through the Morph-summoning overload of this same method.
Compose with another optic under the shared carrier F. Requires AssociativeFunctor[F]. Cross-carrier composition (Lens → Optional, Lens → Traversal, …) goes through the Morph-summoning overload of this same method.
Attributes
- Example
-
case class Address(street: String) case class Person(address: Address) val streetLens = lens[Person](_.address).andThen(lens[Address](_.street)) - Inherited from:
- Optic
- Source
- Optic.scala
True iff a focus satisfies p, via the streaming foldMap under the disjunction monoid — member twin of the generic Optic.exists.
True iff a focus satisfies p, via the streaming foldMap under the disjunction monoid — member twin of the generic Optic.exists.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
Fused foldMap — the default folds the focus vector via the cached pSVecFoldable, skipping the per-call mfFold[PSVec] given instantiation the generic extension pays. Deliberately a plain overridable def, unlike modify: the constructors override it with STREAMING folds that never call to(s) at all — a fold has no use for the reassembly context to must pack, so materializing the focus vector is pure overhead on the read path. Traversal.pEach folds the container directly through Traverse[T], Traversal.selfChildren folds the children vector without the carrier wrapper, and Traversal.composed nests the two sides' folds so a depth-k chain streams with no arrays at any depth. The O(n) allocation win dwarfs the fixed per-call cost the old inline splice protected against.
Fused foldMap — the default folds the focus vector via the cached pSVecFoldable, skipping the per-call mfFold[PSVec] given instantiation the generic extension pays. Deliberately a plain overridable def, unlike modify: the constructors override it with STREAMING folds that never call to(s) at all — a fold has no use for the reassembly context to must pack, so materializing the focus vector is pure overhead on the read path. Traversal.pEach folds the container directly through Traverse[T], Traversal.selfChildren folds the children vector without the carrier wrapper, and Traversal.composed nests the two sides' folds so a depth-k chain streams with no arrays at any depth. The O(n) allocation win dwarfs the fixed per-call cost the old inline splice protected against.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
First focus, if any, via the streaming foldMap under a first-Some monoid — the member twin of the generic Optic.headOption extension, here so concrete Traversals skip the focus vector build (the extension routes through to(s)).
First focus, if any, via the streaming foldMap under a first-Some monoid — the member twin of the generic Optic.headOption extension, here so concrete Traversals skip the focus vector build (the extension routes through to(s)).
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
Focus count via the streaming foldMap — member twin of the generic Optic.length.
Focus count via the streaming foldMap — member twin of the generic Optic.length.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala
Fused modify — same logic as the generic extension, with the cached pSVecFunctor in place of the per-call mfFunctor[PSVec] given instantiation (−40 B/op with replace / foldMap's sibling savings; see the class scaladoc). inline so each call site splices its own copy — per-site monomorphic to / from dispatch.
Fused modify — same logic as the generic extension, with the cached pSVecFunctor in place of the per-call mfFunctor[PSVec] given instantiation (−40 B/op with replace / foldMap's sibling savings; see the class scaladoc). inline so each call site splices its own copy — per-site monomorphic to / from dispatch.
Attributes
- Inherited from:
- Traversal
- Source
- Traversal.scala