# Does Parameters.jl support a Varargs ... constuctor

**URL:** <https://discourse.julialang.org/t/does-parameters-jl-support-a-varargs-constuctor/83100>\
**Category:** General Usage\
**Tags:** parametersjl\
**Created:** [June 21, 2022, 12:30am UTC](https://discourse.julialang.org/t/does-parameters-jl-support-a-varargs-constuctor/83100 "2022-06-21T00:30:54Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Lincoln\_Hannah](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lincoln_hannah/32/19198_2.png) [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Post date:** [June 21, 2022, 12:30am UTC](https://discourse.julialang.org/t/does-parameters-jl-support-a-varargs-constuctor/83100/1 "2022-06-21T00:30:54Z")

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```julia
a,b,c = 1:3

@with_kw mutable struct T
    a
    b    
end

```

`T(;a,b)` works  
`T(;a,b,c)` fails

Can the kwargs constructor have a Varargs component `X...` ?  
It allowed me to create one `T(;a,b, X... ) = T(;a,b)`

But `T(;a,b,c)` then gives a stack overflow error.

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**Author:** ![Henrique\_Becker](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/henrique_becker/32/15443_2.png) [@Henrique\_Becker](https://discourse.julialang.org/u/Henrique_Becker)\
**Post date:** [June 21, 2022, 1:06am UTC](https://discourse.julialang.org/t/does-parameters-jl-support-a-varargs-constuctor/83100/3 "2022-06-21T01:06:41Z")

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> [@Lincoln\_Hannah](#):
>
> Can the kwargs constructor have a Varargs component `X...` ?  
> It allowed me to create one `T(;a,b, X... ) = T(;a,b)`
> 
> But `T(;a,b,c)` then gives a stack overflow error.

I do believe you redefined the _one and unique_ method that has only keyword parameters with your version, so now it just calls itself recursively forever.

Cannot you do `T(;a,b, X... ) = T(a,b)` instead?

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<div class="post-metadata">

**Author:** ![Lincoln\_Hannah](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lincoln_hannah/32/19198_2.png) [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Post date:** [June 21, 2022, 1:12am UTC](https://discourse.julialang.org/t/does-parameters-jl-support-a-varargs-constuctor/83100/4 "2022-06-21T01:12:07Z")

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That works thank you.

Can the kwargs constructor generated by @with\_kw be set to automatically add the Varargs component?