Class FieldList

data

hash

Static_emptyHash

Static_innerProvable

Static_nextHash

Static_provable

Staticempty

Staticfrom

StaticfromReverse

Staticprovable

Constructor

• get Constructor(): typeof MerkleList

  Returns typeof MerkleList

innerProvable

• get innerProvable(): ProvableHashable<T>

  Returns ProvableHashable<T>

StaticemptyHash

• get emptyHash(): Field

  Returns Field

clone

• clone(): MerkleList<Field>

  Returns MerkleList<Field>

forEach

• forEach(
      length: number,
      callback: (element: Field, isDummy: Bool, i: number) => void,
  ): void

  Iterate through the list in a fixed number of steps any apply a given callback on each element.

  Proves that the iteration traverses the entire list. Once past the last element, dummy elements will be passed to the callback.

  Note: There are no guarantees about the contents of dummy elements, so the callback is expected to handle the isDummy flag separately.

  Parameters

  • length: number
  • callback: (element: Field, isDummy: Bool, i: number) => void

  Returns void

isEmpty

• isEmpty(): Bool

  Returns Bool

lengthUnconstrained

• lengthUnconstrained(): Unconstrained<number>

  Returns Unconstrained<number>

nextHash

• nextHash(hash: Field, value: Field): Field

  Parameters

  • hash: Field
  • value: Field

  Returns Field

pop

• pop(): Field

  Remove the last element from the list and return it.

  If the list is empty, returns a dummy element.

  Returns Field

popExn

• popExn(): Field

  Remove the last element from the list and return it.

  This proves that the list is non-empty, and fails otherwise.

  Returns Field

popIf

• popIf(condition: Bool): Field

  Return the last element, but only remove it if condition is true.

  If the list is empty, returns a dummy element.

  Parameters

  • condition: Bool

  Returns Field

popIfUnsafe

• popIfUnsafe(shouldPop: Bool): Field

  Low-level, minimal version of pop() which lets the caller decide whether there is an element to pop.

  I.e. this proves:

  • If the input condition is true, this returns the last element and removes it from the list.
  • If the input condition is false, the list is unchanged and the return value is garbage.

  Note that if the caller passes true but the list is empty, this will fail. If the caller passes false but the list is non-empty, this succeeds and just doesn't pop off an element.

  Parameters

  • shouldPop: Bool

  Returns Field

push

• push(element: Field): void

  Push a new element to the list.

  Parameters

  • element: Field

  Returns void

pushIf

• pushIf(condition: Bool, element: Field): void

  Push a new element to the list, if the condition is true.

  Parameters

  • condition: Bool
  • element: Field

  Returns void

startIterating

• startIterating(): MerkleListIterator<Field>

  Returns MerkleListIterator<Field>

startIteratingFromLast

• startIteratingFromLast(): MerkleListIterator<Field>

  Returns MerkleListIterator<Field>

toArrayUnconstrained

• toArrayUnconstrained(): Unconstrained<Field[]>

  Returns Unconstrained<Field[]>

Staticcreate

• create<T>(
      type: WithProvable<ProvableHashable<T>>,
      nextHash?: (hash: Field, value: T) => Field,
      emptyHash_?: Field,
  ): typeof MerkleList & {
      empty: () => MerkleList<T>;
      from: (array: T[]) => MerkleList<T>;
      fromReverse: (array: T[]) => MerkleList<T>;
      provable: ProvableHashable<MerkleList<T>>;
  }

  Create a Merkle list type

  Optionally, you can tell create() how to do the hash that pushes a new list element, by passing a nextHash function.

  Type Parameters

  • T

  Parameters

  • type: WithProvable<ProvableHashable<T>>
  • OptionalnextHash: (hash: Field, value: T) => Field
  • OptionalemptyHash_: Field

  Returns typeof MerkleList & {
      empty: () => MerkleList<T>;
      from: (array: T[]) => MerkleList<T>;
      fromReverse: (array: T[]) => MerkleList<T>;
      provable: ProvableHashable<MerkleList<T>>;
  }

  Example

  class MyList extends MerkleList.create(Field, (hash, x) =>
    Poseidon.hashWithPrefix('custom', [hash, x])
  ) {}
  Copy