Re: Document/Example how to create "standalone" markup commands

[David Kastrup]

Aaron Hill <address@hidden> writes:

> On 2018-06-07 07:58, David Kastrup wrote:
>> Aaron Hill <address@hidden> writes:
>>
>>> On 2018-06-07 06:34, Aaron Hill wrote:
>>>> Hi David,
>>>>
>>>> Correct me if I am wrong, but the second definition is ***not***
>>>> usable as a
>>>> function.  That is, it cannot accept a parameter for customizing the
>>>> markup.  Unless `\etc` is something magical that is undocumented, the
>>>> resulting `\doubleBox` would have to be a complete idea.
>>>
>>> (See ***correction*** above.)
>>>
>>> I hate email sometimes... No ability to edit when you make a dumb
>>> typing mistake.  Sorry.
>>
>> I don't understand what you consider "not a function" though.  It is a
>> function with constrained form, but a function nevertheless since it
>> takes a text/markup parameter.
>
> There are likely many pedants who would say that functions strictly
> have non-zero arity, but that is neither here nor there.

So?  It has arity one.

> The snippet you mentioned does not work as-is on 2.19.81, so I was
> curious if there was something new going on with how to define
> functions.

It will in 2.21.0.

> As I originally suspected `\etc` was nothing more than a placeholder
> for other, actual markup, your suggested definition of `\doubleBox`
> ultimately becomes a fixed, parameter-less construct.

Uh, isn't that the definition of a function's parameter?

> That is, you could not say `c\doubleBox foo`, which is what Urs was
> trying to achieve.

Uh, you can in current master.

> Is there something potentially unsound about using
> define-event-function to that end?

No.  But if Urs is using current master anyway...

-- 
David Kastrup