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

[Wolfgang Schuster <wolfgang.schuster.lists@gmail.com>]

Joel via ntg-context schrieb am 02.11.2024 um 21:02:
> 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?

When you pass your itemize entries as comma separated list you can use 
the \getcommalistsize command to count the list entries.

Afterwards use \doloopoverlist to create an itemize entry for each text 
in the comma separated list.

%%%% begin example
\starttexdefinition protected thisiymylist [#1]

   \getcommalistsize[#1]

   \doifelse{\commalistsize}{1}
     {Read the prompt below:\par}
     {Read the prompts below:\par}

   \startitemize
   \doloopoverlist{#1}{\startitem\recursestring\stopitem}
   \stopitemize

\stoptexdefinition

\starttext

\thisiymylist
   [Do you think cats should be banned from university dormitories?,
    Should public schools provide free breakfast?]

\thisiymylist
   [Do you think cats should be banned from university dormitories?]

\stoptext
%%%% end example

Wolfgang
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