[NTG-context] How to extend an existing macro to take optional parameters?

[Bruce Horrocks]

> On 14 Mar 2023, at 02:08, Alan Braslau via ntg-context <ntg-context at ntg.nl> wrote:
> 
> Designating "optional" parameters within [...] is a LaTeX notion.
> ConTeXt handles parameters differently.
> 
> Alan

Thanks Alan but I've never used LaTeX so I've no idea what the philosophical differences are.

I wanted three mandatory and two optional params. One of those optional params is not typeset so I assumed it should be [ ] delimited and not { }.

> 
>>> and I'd like to be able to extend it so that any of the following
>>> can be used:
>>> 
>>>   \mycommand{aa}{bb}{cc}
>>>   \mycommand{aa}{bb}{cc}{dd}
>>>   \mycommand{aa}{bb}{cc}{dd}[ee]
>>> 
>>> or
>>> 
>>>   \mycommand[ee]{aa}{bb}{cc}{dd}  % if this is more the ConTeXt way
>>> 
>>> where {dd} is the optional extra parameter and, if it is present,
>>> then [ee] can also be optionally added (because it controls how
>>> {dd} is printed).

—
Bruce Horrocks
Hampshire, UK