# Automatically fusing together several for-loops

**URL:** https://discourse.julialang.org/t/automatically-fusing-together-several-for-loops/46097
**Category:** General Usage
**Created:** [September 5, 2020, 10:49am UTC](https://discourse.julialang.org/t/automatically-fusing-together-several-for-loops/46097 "2020-09-05T10:49:03Z")
**Posts on this page:** 1
**Showing post:** 16

<div class="post-metadata">

### Author: ![tisztamo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tisztamo/32/16200_2.png) [@tisztamo](https://discourse.julialang.org/u/tisztamo)
#### Post date: [September 6, 2020, 11:16am UTC](https://discourse.julialang.org/t/automatically-fusing-together-several-for-loops/46097/16 "2020-09-06T11:16:12Z")

</div>

I got excited from this topic and created a micropackage while my son is sleeping 🙂

[https://github.com/tisztamo/FunctionWranglers.jl](https://github.com/tisztamo/FunctionWranglers.jl)

```julia
  | | |_| | | | (_| | | Version 1.5.1 (2020-08-25)
 _/ |\ __'_|_|_|\__'_| | Official https://julialang.org/ release
|__/ |

julia> using FunctionWranglers

julia> create_adder(value) = (x) -> x + value
create_adder (generic function with 1 method)

julia> adders = [create_adder(i) for i = 1:5]
5-element Array{var"#1#2"{Int64},1}:
 #1 (generic function with 1 method)
 #1 (generic function with 1 method)
 #1 (generic function with 1 method)
 #1 (generic function with 1 method)
 #1 (generic function with 1 method)

julia> w = FunctionWrangler(adders)
FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{Nothing,Nothing}}}}}}(var"#1#2"{Int64}(1), FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{Nothing,Nothing}}}}}(var"#1#2"{Int64}(2), FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{Nothing,Nothing}}}}(var"#1#2"{Int64}(3), FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{Nothing,Nothing}}}(var"#1#2"{Int64}(4), FunctionWrangler{var"#1#2"{Int64},FunctionWrangler{Nothing,Nothing}}(var"#1#2"{Int64}(5), FunctionWrangler{Nothing,Nothing}(nothing, nothing))))))

julia> result = zeros(Float64, length(adders))
5-element Array{Float64,1}:
 0.0
 0.0
 0.0
 0.0
 0.0

julia> smap!(result, w, 10.0)

julia> result
5-element Array{Float64,1}:
 11.0
 12.0
 13.0
 14.0
 15.0

julia> @btime smap!($result, $w, d) setup = (d = rand())
  2.892 ns (0 allocations: 0 bytes)

```

It works well for 200 functions (\<1s compile time at the first call), and seems to be usable up to at least 1000 functions.

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_[View the full topic](https://discourse.julialang.org/t/automatically-fusing-together-several-for-loops/46097)._