Word to the wise..Optional is not optional

[G Gabriel]

I just feel it's necessary to highlight this point:
If a function has optional parameters, let's say:

funciotn(table as c, key as c, [filter as c], [order as c])

You might read that as meaning, if you wish to add a filter, you can but you do not have to, same goes for order.

But that's not so, if you choose to add order but not filter, alpha will interpret that as the filter option (the preceding optional parameter) and it won't work.

Watch the optionals hierarchy. If you enter the second optional, YOU HAVE TO, enter all preceding ones.

I hope I am correct on this. It is not outlined in the help file. It's something I am finding by trial and error.

Gabe

[Keith Hubert]

RE: Word to the wise..Optional is not optional

Gabe,

I'm not 100% on this but if you want to use the second Optional only then there should be a second commer.

Your function would then read as: function(table as c, key as c, ,[order as c])

You can check the correct syntax by converting the code to open a form that has Order perameters only.

RegardsKeith HubertAlpha Guild MemberLondon.KHDB Management Systems

[Tom Cone Jr]

RE: Word to the wise..Optional is not optional

This has not been my experience.

If the function were declared like this:

function(table as c, key as c, [filter as c], [order as c])

I'd use a comma as placeholder to tell Alpha that I was supplying an Order parameter, not a filter parameter.

function("Customer",vc_MyKey,,"Lastname")

In other contexts Alpha will correctly identify "Lastname" as an Order and not as a Filter. Is this not working for you here?

In contrast, if you do this:

function("Customer,vc_Mkey,"Lastname")

Alpha will interpret Lastname as a Filter parameter and probably choke.

-- tom

[G Gabriel]

RE: Word to the wise..Optional is not optional

Keith:
No.
That won't work. I already tried that.
Gabe

[G Gabriel]

RE: Word to the wise..Optional is not optional

Tom:
Ditto my reply to Keith.
I tried function(table,key,,order). It does not work.
Gabe

[Tom Cone Jr]

RE: Word to the wise..Optional is not optional

Check Steve's explanation in the other thread. It seems your example here is different from the syntax used for the function you're working with. -- tom

[Steve Andrews]

RE: Word to the wise..Optional is not optional

Gabe,

Can you give an example of a function whose syntax is:

function(table as c, key as c, [filter as c], [order as c])

and not

function(table as c, key as c, [filter as c, [order as c]])

?

Steve

[G Gabriel]

RE: Word to the wise..Optional is not optional

Steve:
As I replied in the other thread, you make a good point. I guess one has to pay attention to these nestings.
Gabe

[AaronBBrown]

RE: Word to the wise..Optional is not optional

To my knowledge, there are no languages in existence that allow you to arbitrarily specify some random optional parameter without specifying the parameters preceeding it. That wouldn't make any sense, as the computer would have no way of identifying which parameter you *actually* meant, especially if they are all similarly typed.