Style improvements in reduce.jl (#136)

* Style improvements in reduce.jl

* Update reduce.jl

Author: odow

src/reduce.jl

@@ -1,26 +1,37 @@
-function _same_length(a) end
-function _same_length(a, b, c::Vararg{Any,N}) where {N}
+_check_same_length(::Any) = nothing
+
+function _check_same_length(a, b, c::Vararg{Any,N}) where {N}
     if length(a) != length(b)
         throw(
             DimensionMismatch(
-                "one array has length $(length(a)) which does not match the length of the next one, $(length(b)).",
+                "one array has length $(length(a)) which does not match the " *
+                "length of the next one, $(length(b)).",
             ),
         )
     end
-    return _same_length(b, c...)
+    return _check_same_length(b, c...)
 end
+
 reduce_op(op::AddSubMul) = add_sub_op(op)
-reduce_op(op::typeof(add_dot)) = +
+
+reduce_op(::typeof(add_dot)) = +
+
 neutral_element(::typeof(+), T::Type) = zero(T)
+
 map_op(::AddSubMul) = *
+
 map_op(::typeof(add_dot)) = LinearAlgebra.dot
+
 function promote_map_reduce(op::Function, args::Vararg{Any,N}) where {N}
-    return T =
-        promote_operation(op, promote_operation(map_op(op), args...), args...)
+    return promote_operation(
+        op,
+        promote_operation(map_op(op), args...),
+        args...,
+    )
 end
 
 function fused_map_reduce(op::F, args::Vararg{Any,N}) where {F<:Function,N}
-    _same_length(args...)
+    _check_same_length(args...)
     T = promote_map_reduce(op, eltype.(args)...)
     accumulator = neutral_element(reduce_op(op), T)
     buffer = buffer_for(op, T, eltype.(args)...)
@@ -30,11 +41,12 @@ function fused_map_reduce(op::F, args::Vararg{Any,N}) where {F<:Function,N}
     end
     return accumulator
 end
+
 function operate(::typeof(sum), a::AbstractArray)
     return mapreduce(
         identity,
         add!!,
-        a,
+        a;
         init = zero(promote_operation(+, eltype(a), eltype(a))),
     )
 end