//! Shorthands for using [`Context::Fallible`].

use fail::*;

use crate::func::context::*;

use super::*;

/// Preferred [Wrapped] [Result].
pub type FallibleWrapped<'a, Ctx, A, E> = Wrap<'a, A, FallibleMonad<'a, Ctx, E>>;

/// Extention trait for simpler conversion between [`FunctorContext::T`] and [`Context::Fallible`].
///
/// Until either Rust type system or [`crate::func`] take serious changes,
/// this is the preferred way to switch between [Wrapped] and [fallible].
pub trait FallibleContext<'a>: Context<'a> {
    /// Convert a fallible wrapped into a wrapped result.
    fn unstuff<A: 'a, E: 'a>(wa: FallibleWrapped<'a, Self, A, E>) -> WrapC<'a, Result<A, E>, Self> {
        <Self as Context<'a>>::Fallible::unstuff(wa)
    }

    /// Convert a wrapped result into a fallible wrapped.
    fn stuff<A: 'a, E: 'a>(fa: WrapC<'a, Result<A, E>, Self>) -> FallibleWrapped<'a, Self, A, E> {
        <Self as Context<'a>>::Fallible::stuff(fa)
    }
}

impl<'a, Ctx: Context<'a>> FallibleContext<'a> for Ctx {}