Make function arguments FnMut

Closes #59

Author: novacrazy

src/functional.rs

@@ -37,7 +37,7 @@ pub unsafe trait FunctionalSequence<T>: GenericSequence<T> {
         where
             Self: MappedGenericSequence<T, U>,
             Self::Length: ArrayLength<U>,
-            F: Fn(SequenceItem<Self>) -> U,
+            F: FnMut(SequenceItem<Self>) -> U,
     {
         FromIterator::from_iter(self.into_iter().map(f))
     }
@@ -47,12 +47,12 @@ pub unsafe trait FunctionalSequence<T>: GenericSequence<T> {
     ///
     /// If the mapping function panics, any already initialized elements in the new sequence
     /// will be dropped, AND any unused elements in the source sequences will also be dropped.
-    fn zip<B, Rhs, U, F>(self, rhs: Rhs, f: F) -> MappedSequence<Self, T, U>
+    fn zip<B, Rhs, U, F>(self, rhs: Rhs, mut f: F) -> MappedSequence<Self, T, U>
         where
             Self: MappedGenericSequence<T, U>,
             Self::Length: ArrayLength<B> + ArrayLength<U>,
             Rhs: GenericSequence<B>,
-            F: Fn(SequenceItem<Self>, SequenceItem<Rhs>) -> U,
+            F: FnMut(SequenceItem<Self>, SequenceItem<Rhs>) -> U,
     {
         FromIterator::from_iter(self.into_iter().zip(rhs.into_iter()).map(|(l, r)| f(l, r) ))
     }

src/lib.rs

@@ -281,9 +281,9 @@ where
     type Length = N;
     type Sequence = Self;
 
-    fn generate<F>(f: F) -> GenericArray<T, N>
+    fn generate<F>(mut f: F) -> GenericArray<T, N>
     where
-        F: Fn(usize) -> T,
+        F: FnMut(usize) -> T,
     {
         let mut destination = ArrayBuilder::new();
 
@@ -312,11 +312,11 @@ where
     N: ArrayLength<T>,
     Self: GenericSequence<T, Item=T>
 {
-    fn map<U, F>(self, f: F) -> MappedSequence<Self, T, U>
+    fn map<U, F>(self, mut f: F) -> MappedSequence<Self, T, U>
     where
         Self::Length: ArrayLength<U>,
         Self: MappedGenericSequence<T, U>,
-        F: Fn(T) -> U,
+        F: FnMut(T) -> U,
     {
         let mut source = ArrayConsumer::new(self);
 
@@ -331,12 +331,12 @@ where
         }))
     }
 
-    fn zip<B, Rhs, U, F>(self, rhs: Rhs, f: F) -> MappedSequence<Self, T, U>
+    fn zip<B, Rhs, U, F>(self, rhs: Rhs, mut f: F) -> MappedSequence<Self, T, U>
     where
         Self: MappedGenericSequence<T, U>,
         Self::Length: ArrayLength<B> + ArrayLength<U>,
         Rhs: GenericSequence<B>,
-        F: Fn(T, SequenceItem<Rhs>) -> U,
+        F: FnMut(T, SequenceItem<Rhs>) -> U,
     {
         let mut left = ArrayConsumer::new(self);
 

src/sequence.rs

@@ -20,7 +20,7 @@ pub unsafe trait GenericSequence<T>: Sized + IntoIterator {
     /// If the generator function panics while initializing the sequence,
     /// any already initialized elements will be dropped.
     fn generate<F>(f: F) -> Self::Sequence
-        where F: Fn(usize) -> T;
+        where F: FnMut(usize) -> T;
 }
 
 /// Accessor type for iteration items from `GenericSequence`
@@ -35,7 +35,7 @@ where
 
     #[inline]
     fn generate<F>(f: F) -> Self::Sequence
-        where F: Fn(usize) -> T
+        where F: FnMut(usize) -> T
     {
         S::generate(f)
     }
@@ -50,7 +50,7 @@ where
 
     #[inline]
     fn generate<F>(f: F) -> Self::Sequence
-        where F: Fn(usize) -> T
+        where F: FnMut(usize) -> T
     {
         S::generate(f)
     }