# How to use \`invoke\` with a functor

**URL:** <https://discourse.julialang.org/t/how-to-use-invoke-with-a-functor/91949>\
**Category:** General Usage\
**Created:** [December 21, 2022, 12:22pm UTC](https://discourse.julialang.org/t/how-to-use-invoke-with-a-functor/91949 "2022-12-21T12:22:23Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![abraunst](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraunst/32/6880_2.png) [@abraunst](https://discourse.julialang.org/u/abraunst)\
**Post date:** [December 21, 2022, 12:22pm UTC](https://discourse.julialang.org/t/how-to-use-invoke-with-a-functor/91949/1 "2022-12-21T12:22:23Z")

</div>

This is maybe a stupid question, but I couldn’t find the answer in the documentation. I need it mainly for debugging, but a minimal example would be

```julia
abstract type A end
(::A)() = "A"
struct B <: A end
(::B)() = "B"
b = B()
b()

```

How to call the first method from `b` ? I.e. is there any syntax for the call function to use with `invoke`?