Assign register value to TYPO3 CASE key - typo3

Question

Am making some complex menus and would like to use CASE (or similar) to determine the number of submenus in a given branch in order to determine the style of menu to use.
Code:
5 = HMENU
5 {
entryLevel = -1
1 = TMENU
1 {
expAll = 1
NO = 1
NO {
...
}
IFSUB = 1
IFSUB {
10 = CASE
10 {
key.data = {register:count_menuItems}
1 = COA
1 {
data = {field:title}
data.insertData = 1
}
2 = COA
2 {
data = {field:title}
data.insertData = 1
}
default = COA
default {
data = {field:title}
data.insertData = 1
}
}
wrapItemAndSub = |
}
}
2 = TMENU
2 {
maxItems = 2
expAll = 1
...
}
}
How can I get CASE to work? I've tried it with and without the braces.

Answer 1

you should get more information how to access fields, register and other data in typoscript.
if you have a property you mostly can modify the way to get other information than a constant text.
In your example it is the key property where constants are not meaningful.
if you want to access a field of the 'current' record/data you just use key.field = fieldname
if it is other data you modify it to key.data = register:registername
accessing a field can be done with key.data = field:fieldname
If you want these data connected to other information you could use a wrap:
key.data = register:registername
key.wrap = prefix- | -suffix
Notice: the parts of the wrap are trimmed before they are connected
another way would be an inline notation where you even can use multiple values:
key = {register:registername}-with-{field:fieldname}
key.insertData = 1
here you have two replacements. each has to be wrapped in braces {} and you need to tell TYPO3 that there are replacements to do: insertData = 1
special case TEXTobject:
10 = TEXT
10.value = constant Text
20 = TEXT
20.field = fieldname
30 = TEXT
30.data = register:registername
40 = TEXT
40.value = register is '{register:registername}' and field is '{field:fieldname}'
40.insertData = 1
ADDED:
see the manual of the typoscript data type getText where you can find what else can be used instead of register:
then the manual entry for data which is a property of the function .stdWrap and of type getText.
This entry is followed by the property field stating, it is a shortcut for data = field:
(This explaines why your COA with .data results in anything, as doing a .stdWrap.data on any object will replace the object's content.)
be aware that field (either as property or as key of getText) will select
a field of the current record, which might vary dependent on context:
for page rendering it is the record of the current page (table pages),
for rendering a content element it is the element (table tt_content),
inside a filesProcessor it is a file (table sys_file_reference`),
in the renderObj of CONTENT, RECORDS, or split it is the selction you define.

Answer 2

Found the answer. As far as I can tell, CASE works on stdwrap.cObjects and so the code
10 = CASE
10 {
key.data = {register:count_menuItems}
...
}
should be
stdWrap.cObject = CASE
stdWrap.cObject {
key.data = register:count_menuItems
if.isTrue.data = register:count_menuItems
...
}
This way it works.