//! Modifying a model during search.

//!

//! Incremental solving can be triggered for a solverthrough the

//! [`Solver::solve_mut`] method.

//!

//! This gives access to a [`ModelModifier`] in the solution retrieval callback.

use crate::ast::{Domain, Expression, Name};

use super::private;

use super::Solver;

/// A ModelModifier provides an interface to modify a model during solving.

///

/// Modifications are defined in terms of Conjure AST nodes, so must be translated to a solver

/// specfic form before use.

///

/// It is implementation defined whether these constraints can be given at high level and passed

/// through the rewriter, or only low-level solver constraints are supported.

///

/// See also: [`Solver::solve_mut`].

pub trait ModelModifier: private::Sealed {

}

/// A [`ModelModifier`] for a solver that does not support incremental solving. Returns

/// [`OperationNotSupported`](`ModificationFailure::OperationNotSupported`) for all operations.

pub struct NotModifiable;

impl private::Sealed for NotModifiable {}

impl ModelModifier for NotModifiable {}

/// The requested modification to the model has failed.

#[non_exhaustive]

pub enum ModificationFailure {

    /// The desired operation is not supported for this solver adaptor.

    OpNotSupported,

    /// The desired operation is supported by this solver adaptor, but has not been

    /// implemented yet.

    OpNotImplemented,

    // The arguments given to the operation are invalid.

    ArgsInvalid(anyhow::Error),

    /// An unspecified error has occurred.

    Error(anyhow::Error),

}