ExDatalog.Constraints.Membership (ExDatalog v0.2.0)

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Membership constraint implementation for the Constraint behaviour.

Evaluates membership constraints (:member) which filter bindings based on whether a value is present in a constant list. The left operand must be bound; the right operand must be a constant list. Returns :filter when the value is not in the list or the left variable is unbound.

Summary

Functions

evaluate(constraint, binding, context)

Evaluates a membership constraint against a binding environment.

Functions

evaluate(constraint, binding, context)

@spec evaluate(
  ExDatalog.IR.Constraint.t(),
  ExDatalog.Engine.Binding.t(),
  ExDatalog.Constraint.Context.t()
) :: {:ok, ExDatalog.Engine.Binding.t()} | :filter

Evaluates a membership constraint against a binding environment.

Accepts an IR.Constraint struct as produced by the compiler. Returns {:ok, binding} (unchanged) when the left value is a member of the right list, or :filter when it is not or the left variable is unbound.