why can i define this function? julia> f(y,x...)=+(x...).*y f (generic function with 1 method) and can’t I define this other one? julia> f1(x...,y)=+(x...).*y ERROR: syntax: invalid "..." on non-final Couldn’t we gnisrap the arguments in reverse order? I guess there are many possible side eff…

This seems to be about slurping, not about optional arguments. Here’s a PR that addresses this: https://github.com/JuliaLang/julia/pull/42902 Not sure when/if it will land. But currently, this is not allowed.

Note that the PR doesn’t address method dispatch as the OP asked for. That would require changes to the type system to actually be able to represent signatures like this.

Slurping on non-final argument

Internals & Design

mbaz April 8, 2022, 2:14pm 2

See this thread: Optional positional arguments must occur at end - #13 by Jean_Michel

Topic		Replies	Views
Optional positional arguments must occur at end Internals & Design	12	3038	April 6, 2022
Slurping in not final position General Usage function-parameters , destructuring	11	458	August 15, 2023
Variable Keword arguments should be Final New to Julia question	2	103	July 22, 2024
Are Vararg only allowed as a final argument and if so why? General Usage	6	880	April 25, 2019
Optional positional arguments at the begining New to Julia question , agents	4	234	September 27, 2024

Slurping on non-final argument

Related topics