Hello,

I’m experiencing some strange behavior when executing the following query in the BaseX 9.2.4 GUI (nevermind the awkward query structure – that is just to be able to inspect the results of the individual evaluation steps):

let $t := <x>200.0000</x>

let $num := number($t)

let $gt5000 := $num gt 5000

let $ltMinus5000 := $num lt -5000

return $gt5000 or $ltMinus5000

The result is true, although it should be false.

The compilation and optimization logs for this query in the GUI tell us the following:

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Compiling:

- rewrite > comparison to range comparison: ($num_1 > 5000) -> ($num_1 >= 5000.000000000001)

- rewrite 'gt' comparison to range comparison: ($num_1 gt 5000) -> ($num_1 >= 5000.000000000001)

- pre-evaluate unary expression to xs:integer item: -5000

- rewrite < comparison to range comparison: ($num_1 < -5000) -> ($num_1 <= -5000.000000000001)

- rewrite 'lt' comparison to range comparison: ($num_1 lt -5000) -> ($num_1 <= -5000.000000000001)

- inline $gt5000_2

- inline $ltMinus5000_3

- simplify or: (true())

- pre-evaluate or to xs:boolean item: (true()) -> true()

- remove unused variable $num_1

- remove unused variable $t_0

- simplify FLWOR expression: true()

Optimized Query:

true()

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When the return statement is changed to “return ($num,$gt5000,$ltMinus5000,$gt5000 or $ltMinus5000)” then the result of the boolean operation (last element of the result sequence) is false, as expected.

The GUI log then is:

----------

Compiling:

- rewrite > comparison to range comparison: ($num_1 > 5000) -> ($num_1 >= 5000.000000000001)

- rewrite 'gt' comparison to range comparison: ($num_1 gt 5000) -> ($num_1 >= 5000.000000000001)

- pre-evaluate unary expression to xs:integer item: -5000

- rewrite < comparison to range comparison: ($num_1 < -5000) -> ($num_1 <= -5000.000000000001)

- rewrite 'lt' comparison to range comparison: ($num_1 lt -5000) -> ($num_1 <= -5000.000000000001)

Optimized Query:

let $t_0 := element x { ("200.0000") } let $num_1 := number($t_0) let $gt5000_2 := ($num_1 >= 5000.000000000001) let $ltMinus5000_3 := ($num_1 <= -5000.000000000001) return ($num_1, $gt5000_2, $ltMinus5000_3, ($gt5000_2 or $ltMinus5000_3))

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Am I missing something, or could this be a bug in BaseX 9.2.4? With BaseX 9.0.2, both queries (with the different return statements) returned the expected value false for the boolean operation.

Best regards,

Johannes