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

4 Nov 2024

      On 11/3/2024 5:53 PM, Bruce Horrocks wrote:
...
\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
There is actually some info when you are in an itemize:

\currentitemindex
\currentnofitems

So it's not too hard to get the upcoming value of \currentnofitems:

(1) an extra helper in strc-itm.mkxl

\permanent\tolerant\protected\def\upcomingnofitems[#1]%
   {\the\numexpr
      \clf_analyzeupcomingitemgroup
        {\ifempty{#1}\v!itemize\else#1\fi}%
        \numexpr\c_strc_itemgroups_nesting+\plusone\relax
      \c_strc_itemgroups_max_items
    \relax}

(2) a few line patch in strc-itm.lmt

local function analyzeitemgroup(name,level,upcoming)
     local n = counts[name]
     local u = false
     if level == 1 then
         n = n + 1
         counts[name] = n
         u = upcoming and true
     end
     local items = 0
     local width = 0
     local itemgroup = collected[name]
     if itemgroup then
         local entry = itemgroup[n]
         if entry then
             local l = entry[level]
             if l then
                 items = l[1] or 0
                 width = l[2] or 0
             end
         end
     end
     if u then
         counts[name] = n - 1
     end
     texsetcount(c_strc_itemgroups_max_items,items)
     texsetdimen(d_strc_itemgroups_max_width,width)
end

plus extra:

implement {
     name      = "analyzeupcomingitemgroup",
     actions   = analyzeitemgroup,
     arguments = { "string", "integer", true }
}

And then for Bruce to come up with the singular / plural variant for

This list has \upcomingnofitems[MyItems] entries

\startMyItems
\item cat
\item dog
\item tree
\stopMyItems

This list has \upcomingnofitems\ entries

\startitemize
\item cat
\item dog
\item tree
\stopitemize

Hans

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