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/* // TODO: replace the 3 macros with 3 functions once they work correctly with // reference arguments. // (The returned closure must implement the for<'a> Fn(T, U<'a>)... // TODO: replace the 3 macros/functions with a generic function when it can // accept any number of arguments. /// Wraps a `FnMut` into a `Fn` /// /// This can be used to use a `FnMut` when a callack expects a `Fn`. /// /// # Note /// /// If the resulting `Fn` is called recursively, subsequent calls will be /// no-ops. pub fn immutify<F: FnMut(&mut Cursive)>( f: F, ) -> impl for<'s> Fn(&'s mut Cursive) { let callback = RefCell::new(f); move |s| { // Here's the weird trick: if we're already borrowed, // just ignored the callback. if let Ok(mut f) = callback.try_borrow_mut() { // Beeeaaah that's ugly. // Why do we need to manually dereference here? (&mut *f)(s); } } } */ /// Macro to wrap a `FnMut` with 1 argument into a `Fn`. /// /// This can wrap any `FnMut` with a single arguments (for example `&mut Cursive`). /// /// See [`immut2!`] and [`immut3!`] to support a different number of arguments. /// /// # Note /// /// If this function tries to call itself recursively (for example by /// triggering an event in `Cursive`), the second call will be a no-op. /// Enabling recursive calls would break the `FnMut` contract. /// /// In addition, due to weird interaction between Higher-rank trait bounds and /// closures, you should use the result from the macro directly, and not /// assign it to a variable. /// /// # Examples /// /// ```rust /// # #[macro_use] /// # extern crate cursive; /// # use cursive::Cursive; /// # fn main() { /// # let mut siv = Cursive::dummy(); /// let mut i = 0; /// // `Cursive::add_global_callback` takes a `Fn(&mut Cursive)` /// siv.add_global_callback('q', immut1!(move |s: &mut Cursive| { /// // But here we mutate the environment! Crazy! /// i += 1; /// if i == 5 { /// s.quit(); /// } /// })); /// # } /// ``` #[macro_export] macro_rules! immut1 { ($f:expr) => {{ let callback = ::std::cell::RefCell::new($f); move |s| { if let Ok(mut f) = callback.try_borrow_mut() { (&mut *f)(s) } } }}; } /// Macro to wrap a `FnMut` with 2 arguments into a `Fn`. /// /// This can wrap any `FnMut` with two arguments. /// /// See [`immut1!`] and [`immut3!`] to support a different number of arguments. /// /// # Note /// /// If this function tries to call itself recursively (for example by /// triggering an event in `Cursive`), the second call will be a no-op. /// Enabling recursive calls would break the `FnMut` contract. /// /// In addition, due to weird interaction between Higher-rank trait bounds and /// closures, you should use the result from the macro directly, and not /// assign it to a variable. #[macro_export] macro_rules! immut2 { ($f:expr) => {{ let callback = ::std::cell::RefCell::new($f); move |s, t| { if let Ok(mut f) = callback.try_borrow_mut() { (&mut *f)(s, t) } } }}; } /// Macro to wrap a `FnMut` with 3 arguments into a `Fn`. /// /// This can wrap any `FnMut` with three arguments. /// /// See [`immut1!`] and [`immut2!`] to support a different number of arguments. /// /// # Note /// /// If this function tries to call itself recursively (for example by /// triggering an event in `Cursive`), the second call will be a no-op. /// Enabling recursive calls would break the `FnMut` contract. /// /// In addition, due to weird interaction between Higher-rank trait bounds and /// closures, you should use the result from the macro directly, and not /// assign it to a variable. #[macro_export] macro_rules! immut3 { ($f:expr) => {{ let callback = ::std::cell::RefCell::new($f); move |s, t, u| { if let Ok(mut f) = callback.try_borrow_mut() { (&mut *f)(s, t, u) } } }}; }