[NTG-context] Re: How can a macro check how many items are in a list?

On 2 Nov 2024, at 20:02, Joel via ntg-context wrote:

Suppose I have a macro like this:

\define[1]\thisismylist{

This list has n items.

\startitemize #1 \stopitemize

}

And in the document it might have this:

\thisismylist{ \item cat \item dog \item tree }

How can I make n display three, as there are three items?

"This list has 3 items:

1. cat 2. dog 3. tree

I will use this as a means to check if the description before a list needs a plural or not:

Read the prompts below:

- Do you think cats should be banned from university dormitories? - Should public schools provide free breakfast?

And that way, if there is only one prompt, it changes the instructions to be:

Read the prompt below:

- Do you think cats should be banned from university dormitories?

If your actual items are more complex than those in your example and Wolfgang’s suggestion of iterating over a comma separated list won’t work then ... The following code stores the length of each list in a dataset. The `delay` option ensures the values retrieved are those from the completed run of the document, and a unique id is assigned to each list so subsequent lists don’t overwrite the length calculations for earlier ones. \definecounter [MyItemsCounter] \definecounter [MyItemsUniqueID] [way=bytext] \setcounter [MyItemsUniqueID] [1] \definedataset [MyItems] [delay=yes] \defineitemgroup [MyItems] \setupitemgroup [MyItems] [ before={\setcounter[MyItemsCounter][1]}, inbetween={\incrementcounter[MyItemsCounter]}, after={\setdataset[MyItems][\rawcountervalue[MyItemsUniqueID]][count=\rawcountervalue[MyItemsCounter]]% \incrementcounter[MyItemsUniqueID]}, ] \define\listLen{\datasetvariable{MyItems}{\rawcountervalue[MyItemsUniqueID]}{count}} \define\itemOrItems{\doifelse{\datasetvariable{MyItems}{\rawcountervalue[MyItemsUniqueID]}{count}}{1}{item}{items}} \starttext This list has \listLen\ \itemOrItems. \startMyItems \item cat \item dog \item tree \stopMyItems \blank This list has \listLen\ \itemOrItems. \startMyItems \item cow \stopMyItems \stoptext Regards, — Bruce Horrocks Hampshire, UK