# Behavior of \\circ\<tab\>

**URL:** <https://discourse.julialang.org/t/behavior-of-circ-tab/113560>\
**Category:** New to Julia\
**Tags:** question\
**Created:** [April 27, 2024, 10:14am UTC](https://discourse.julialang.org/t/behavior-of-circ-tab/113560 "2024-04-27T10:14:46Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![d\_b](https://avatars.discourse-cdn.com/v4/letter/d/ac91a4/32.png) [@d\_b](https://discourse.julialang.org/u/d_b)\
**Post date:** [April 27, 2024, 10:14am UTC](https://discourse.julialang.org/t/behavior-of-circ-tab/113560/1 "2024-04-27T10:14:46Z")

</div>

Inside “manual/functions” under “Function composition and piping”, the first example of using `\circ<tab>` is

` julia> (sqrt \circ<tab> +)(3, 6)`

which evaluates to 3.0. However, when I try to do the same thing with `\sqrt<tab>` instead of just `sqrt`, it gives an error “`\circ<tab>` not a unary operator”. Like this:

`julia> (\sqrt<tab> \circ<tab> +)(3, 6)`

Can somebody explain to me why that is, please? I can’t figure it out, as I’m not familiar enough with the overall language yet.

Thanks in advance!

---

<div class="post-metadata">

**Author:** ![screw\_dog](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/screw_dog/32/48119_2.png) [@screw\_dog](https://discourse.julialang.org/u/screw_dog)\
**Post date:** [April 27, 2024, 10:19am UTC](https://discourse.julialang.org/t/behavior-of-circ-tab/113560/2 "2024-04-27T10:19:12Z")

</div>

I think it’s because `\sqrt` is a prefix operator, not a normal function, so it has a different parsing precedence. But `((\sqrt<tab>) \circ<tab> +)(3, 6)` works fine.

---

<div class="post-metadata">

**Author:** ![d\_b](https://avatars.discourse-cdn.com/v4/letter/d/ac91a4/32.png) [@d\_b](https://discourse.julialang.org/u/d_b)\
**Post date:** [April 27, 2024, 10:24am UTC](https://discourse.julialang.org/t/behavior-of-circ-tab/113560/3 "2024-04-27T10:24:52Z")

</div>

That seems to be the reason, thank you! It also explains this:

```julia
julia> sqrt == \sqrt<tab> 
true

```

but

```julia
julia> \sqrt<tab> == sqrt
== not a unary operator

```