# Fixing the Piping/Chaining/Partial Application Issue (Rev 2)

**URL:** <https://discourse.julialang.org/t/fixing-the-piping-chaining-partial-application-issue-rev-2/90408>\
**Category:** Internals & Design\
**Tags:** proposal, piping, chaining, partial-evaluation, threading\
**Created:** [November 17, 2022, 3:36pm UTC](https://discourse.julialang.org/t/fixing-the-piping-chaining-partial-application-issue-rev-2/90408 "2022-11-17T15:36:57Z")\
**Posts on this page:** 1\
**Showing post:** 26

<div class="post-metadata">

**Author:** ![uniment](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/uniment/32/24532_2.png) [@uniment](https://discourse.julialang.org/u/uniment)\
**Post date:** [November 19, 2022, 11:11am UTC](https://discourse.julialang.org/t/fixing-the-piping-chaining-partial-application-issue-rev-2/90408/26 "2022-11-19T11:11:13Z")

</div>

> [@jar1](#):
>
> My initial instinct is that the commas are just annoying and don’t add much value.

I’ve decided that I agree with you, and I’ve updated the spec and examples for block expressions accordingly. ~~In block mode the commas are now optional, similar to how `Vector`s work.~~

I’m also playing around more with functor composition, and it’s looking super clean.

> **I've updated the demo code to reflect these changes here, as well as supporting some more (though still not all) broadcasting cases.**
>
> ```julia
> see github https://github.com/uniment/ChainingDemo.jl
> 
> ```

> **Here are updated demo examples.**
>
> ```julia
> See github https://github.com/uniment/ChainingDemo.jl
> 
> ```

Also, here are some new demos that work now:

```julia

demo" (1,2,3)--abs2.(_) "
demo" (_+2+3) "
demo" (_-2-3) "
demo" 1--(_+2+3) "
demo" 1--(_-2-3) "
demo" tan(sin(cos(_)))--acos(asin(atan(_))) "
demo" tan(sin(cos(_)))--acos(asin(atan(_))) "(1)
demo" cos(_)--sin--tan--atan--asin--acos "
demo" cos(_)--sin--tan--atan--asin--acos "(1)
demo" --(cos; sin; tan; atan; asin; acos) "
demo" --(cos; sin; tan; atan; asin; acos) "(1)
demo" --cos--sin--tan--atan--asin--acos "
demo" --cos--sin--tan--atan--asin--acos "(1)
# cos--sin--tan--atan--asin--acos doesn't work,
# because sin(::Function) is not defined.
# Should it be though? 🤔 When a method for f(x::T) isn't found,
# if T is a callable type, should f∘x be returned?
demo" (a=1,)--(_.a+1; it+it^2) "
demo" ((1,2),(2,3),(3,4)).--(_[1]^2 + 1) "
demo" 1--((1,2,3)[_+1]) "
demo" (0:10)--filter(isodd, _)--map(_/2+1, _) "
demo" [(a=i,) for i=0:10]--filter(_.a%3==0, _) "
demo"""
"a=1 b=2 c=3"--begin
    split
    it.--(split(_,"="); (it[1]--Symbol => parse(Int,it[2])))
    NamedTuple
end
"""
using DataFrames
df = DataFrame(id=1:100, group=rand(1:5, 100), age=rand(1:30, 100));
demo"""
df--begin
    dropmissing
    filter(:id => (_%5==0), _)
    groupby(_, :group)
    combine(_, :age => sum)
end
"""
demo" (0:0.25:1).--atan(cos(π*_)) "
demo" [1,2,3]--((l=length(it); it); sum(it)/l) "
demo" 1--(it+1, it-2) "
demo" 1--[it+1, it-2] "
demo" 1--Dict(:a=>it+1, :b=>it-2) "
demo" 1--Set((it+1, it-2)) "
demo" (1,2,3)--[i^2 for i ∈ it] "
demo" (1,2,3)--[(i*_)^2 for i ∈ it] "

```

---

_[View the full topic](https://discourse.julialang.org/t/fixing-the-piping-chaining-partial-application-issue-rev-2/90408)._