ExDatalog.Constraints.Arithmetic (ExDatalog v0.2.0)

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Arithmetic constraint implementation for the Constraint behaviour.

Evaluates arithmetic constraints (:add, :sub, :mul, :div) which bind a result variable. All arithmetic is integer-only. Division by zero filters the binding.

This module is the canonical evaluator for arithmetic operations. It is dispatched to by ExDatalog.Constraint.evaluate/3 when the constraint's op is :add, :sub, :mul, or :div.

Summary

Functions

evaluate(constraint, binding, context)

Evaluates an arithmetic 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 an arithmetic constraint against a binding environment.

Accepts an IR.Constraint struct as produced by the compiler. Returns {:ok, extended_binding} when the arithmetic succeeds (result variable is bound), or :filter when division by zero occurs or an input variable is unbound.