#data
boolean(1)
#result
true

#data
boolean(0)
#result
false

#data
boolean (1 div 0)
#result
true

#data
boolean (1 div -0)
#result
true

#data
boolean (0 div 0)
#result
false

#data
boolean (1 div (1 div 0))
#result
false

#data
boolean (1 div (1 div -0))
#result
false

#data
boolean (120 + 523)
#result
true

#data
boolean (1 = 1)
#result
true

#data
boolean (1 = 0)
#result
false

#data
boolean ("abc")
#result
true

#data
boolean ("")
#result
false

#data
boolean ("agaewe  ee")
#result
true

#xml 1
<p>aaagt<!----><q x=""/>e</p>

#data
boolean (/)
#result 1
true

#data
boolean (/abc)
#result 1
false

#data
boolean (//@*)
#result 1
true

#data
boolean (//@aa)
#result 1
false

#data
not (1 = 1)
#result
false

#data
not (0 = 1)
#result
true

#data
not ("abc")
#result
false

#data
not ("")
#result
true

#data
not (0)
#result
true

#data
not (124)
#result
false

#data
true()
#result
true

#data
false()
#result
false

#xml 2
<p>aaa<q xml:lang="en">f<x>o</x>o</q>as<q xml:lang="en-">aa</q><r xml:lang="fr-fr">zz</r>e</p>

#data
lang("en")
#result 2 /
false
#result 2 /1
false
#result 2 /1/1
false
#result 2 /1/2
true

#data
//*[lang("en") ]
#result 2
/1/2
/1/2/2
/1/4

#xml 3
<q><para xml:lang="en"/><div xml:lang="en"><para/></div><para xml:lang="EN"/><para xml:lang="en-us"/></q>

#data
//*[lang("en")]
#result 3
/1/1
/1/2
/1/2/1
/1/3
/1/4

#data
//para[lang("en")]
#result 3
/1/1
/1/2/1
/1/3
/1/4

#data
//para[lang("EN")]
#result 3
/1/1
/1/2/1
/1/3
/1/4

#xml 4
<p>aa<para xml:lang="">a</para><para xml:lang="-">bb</para></p>

#xml 5
<p>aa<para xml:lang="-">a</para><para xml:lang="--ab">bb</para></p>

#data
//para[lang("")]
#result 3
#result 4
/1/2
/1/3

#data
//para[lang("en-US")]
#result 3
/1/4
#result 4

#data
//para[lang("-")]
#result 3
#result 4
/1/3
#result 5
/1/2
/1/3

#html 6
<p lang=en>aaa<p lang><br xml:lang="en">

#data
//*[lang("en")]
#result 6