Did you mean parameter as in input field shown
to the user? Like a combobox or text field?

Since this happened to come up earlier today, here's
a rejected pull request which added a password
parameter - that ought to give you a rough idea:

https://github.com/galaxyproject/galaxy/pull/393

Peter

On Fri, Jul 15, 2016 at 7:46 PM, Katherine Beaulieu
<katherine.beaulieu014@gmail.com> wrote:
> Hi everyone,
> I am looking to implement a new parameter type for galaxy tool development.
> Does anyone know what would be involved in doing something like this or
> perhaps what files would need to be edited?
>
>
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