Count specific children only through XPath - xslt

Question

I have a situation where I have to find the count of few Boolean field values only if they are true.
Input XML:
<PersonInfo>
<ArrayOfPersonInfo>
<CertAsAdultFlag>true</CertAsAdultFlag>
<DeceasedFlag>true</DeceasedFlag>
<WantedFlag>false</WantedFlag>
<CPSORFlag>true</CPSORFlag>
<ConditonalReleaseFlag>false</ConditonalReleaseFlag>
<ProbationFlag>true</ProbationFlag>
<MissingFlag>true</MissingFlag>
<ATLFlag>true</ATLFlag>
<CCWFlag>false</CCWFlag>
<VictimIDTheftFlag>true</VictimIDTheftFlag>
</ArrayOfPersonInfo>
</PersonInfo>
I need to find the count of these flags with the condition if they are 'true'.
Here is what I tried and was unsuccessful with:
<xsl:variable name="AlertCount" select="
count(
PersonInfo/ArrayOfPersonInfo[
CPSORFlag[.='true'] | CertAsAdultFlag[.='true'] |
DeceasedFlag[.='true'] | WantedFlag[.='true'] |
ConditonalReleaseFlag[.='true'] | MissingFlag[.='true'] |
ATLFlag[.='true'] | ProbationFlag[.='true'] | CCWFlag[.='true'] |
VictimIDTheftFlag[.='true'] | CHRIFlag[.='true'] |
CivilWritFlag[.='true'] | MentalPetitionFlag[.='true'] |
ProtectionOrderFlag[.='true'] | juvWantedFlag[.='true'] |
WeaponsFlag[.='true'] | WorkCardFlag[.='true']
]
)
"/>
I really need help with this from someone as I've been trying hard to get through it. Thanks in advance.

Answer 1

<xsl:variable name="AlertCount" select="count(PersonInfo//*[. = 'true'])" />
Here's why your's does not work:
The square brackets in your approach create a predicate over a node set.
That node-set was the union of all mentioned child nodes who fulfilled their condition. A non-empty node-set evaluates to true, a non-empty one to false.
In consequence your count() would always be 1 if any of the children were true and always be 0 if all of them were false.
In other words: You selected one <ArrayOfPersonInfo> node. If it fulfilled a condition (having any number of children with 'true' as their value) it was counted, otherwise not.
After clarification in the comments ("I need to worry only about the flags I mentioned in the above XML"):
<xsl:variable name="AlertCount" select="
count(
PersonInfo//*[
self::CPSORFlag or
self::CertAsAdultFlag or
self::DeceasedFlag or
self::WantedFlag or
self::ConditonalReleaseFlag or
self::MissingFlag or
self::ATLFlag or
self::ProbationFlag or
self::CCWFlag or
self::VictimIDTheftFlag or
self::CHRIFlag or
self::CivilWritFlag or
self::MentalPetitionFlag or
self::ProtectionOrderFlag or
self::juvWantedFlag or
self::WeaponsFlag or
self::WorkCardFlag
][. = 'true']
)
" />