Struct ModelWithdraw

pub struct ModelWithdraw;

Withdraw plugin family’s child model over the LazyBalance’s compile-time marker via ShareBalanceContext.

Bound to ShareBalanceFamily via LazyBalanceRoot::Withdraw.

Overview

Resolves a LazyBalance::Receipt into a concrete asset value and updates the balance state accordingly.

This burns shares (issued) and reduces effective, returning the derived value to the caller.

Derivation

Withdrawal value is computed relative to:

• receipt’s shares
• receipt’s bias (at deposit time)
• current balance bias (price per share)

value = shares * receipt_bias * (current_bias / receipt_bias) // or
      = shares * current_bias // if balance drained after deposit hence receipt is outdated

Although the formula simplifies to shares * current_bias if the receipt gets outdated due to a recent drain, the stored receipt_bias is required to correctly handle:

• drain scenarios
• checkpoint-based invalidation
• historical pricing context

Special handling:

• if balance was drained after receipt checkpoint:
  • receipt bias is reset (treated as 1:1)
  • shares map directly to value

Effect

• effective -= withdraw
• issued -= shares

Edge Cases

• withdrawal is capped at effective
• full withdrawal resets or reinitializes balance

Semantics

Withdrawal represents lazy resolution of ownership:

• receipts encode relative claim
• value is derived at execution time
• drained states are handled via checkpoint logic

Trait Implementations

impl Debug for ModelWithdraw

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ModelWithdraw

fn default() -> ModelWithdraw

Returns the “default value” for a type.

impl<'a, T, In, Out> PurePluginModel<In, ShareBalanceContext<T>, Out> for ModelWithdraw

where T: LazyBalance<Input<'a> = In, Output<'a> = Out>, Context<T>: VirtualError<LazyBalanceError, Error = ShareBalanceError>, Out: LazyBalanceOutput<'a, T::Asset, T::Receipt, T::SnapShot, T::Time, T::Limits, T>, In: LazyBalanceInput<'a, T::Balance, T::Variant, T::Id, T::Asset, T::Receipt, T>, T::Asset: From<<T::Rational as FixedPointNumber>::Inner>,

fn compute(&self, input: In, _context: &ShareBalanceContext<T>) -> Out

Computes the model’s output for a given immutable input and context.