Re: [basex-talk] Question: trying to make a higher-order function in a Java module

[Gunther Rademacher]

Hi Nico,

the code in your project seems to have dependencies that cannot be resolved. This is from the log of mvn install:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.539 s
[INFO] Finished at: 2024-11-15T18:43:46+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project basex-ner-xar: Could not resolve dependencies for project com.rakensi:basex-ner-xar:jar:1.0.2
[ERROR] dependency: org.greenmercury:SMAX:jar:1.0.4 (compile)
[ERROR]         Could not find artifact org.greenmercury:SMAX:jar:1.0.4 in central (https://repo.maven.apache.org/maven2)
[ERROR] dependency: com.rakensi:XML-NER:jar:1.0.5 (compile)
[ERROR]         Could not find artifact com.rakensi:XML-NER:jar:1.0.5 in central (https://repo.maven.apache.org/maven2)
[ERROR]
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException

 

Anyway, would it maybe possible for you to provide an even smaller, self-contained example that demonstrates the failure? I have tried the following, which works both with a dynamic and a static variable holding the function item:

 

package test;

 

import static org.basex.query.value.type.SeqType.*;

 

import org.basex.query.*;

import org.basex.query.expr.*;

import org.basex.query.util.list.*;

import org.basex.query.value.*;

import org.basex.query.value.item.*;

import org.basex.query.value.type.*;

import org.basex.query.var.*;

import org.basex.util.hash.*;

 

public class Test extends QueryModule

{

public FuncItem makeFunction() throws QueryException {

final Var var = new VarScope().addNew(new QNm("input"), STRING_O, queryContext, null);

final Var[] params = { var };

final Expr[] exprs = new Expr[] { new VarRef(null, var) };

final FuncType funcType = FuncType.get(SeqType.STRING_O, STRING_O);

final TestFunction tf = new TestFunction(exprs);

return new FuncItem(null, tf, params, AnnList.EMPTY, funcType, params.length, null);

}

 

private static final class TestFunction extends Arr {

 

protected TestFunction(final Expr[] args) {

super(null, SeqType.STRING_O, args);

}

 

@Override

public Value value(final QueryContext qc) throws QueryException {

return arg(0).value(qc);

}

 

@Override

public Expr copy(final CompileContext cc, final IntObjMap<Var> vm) {

return copyType(new TestFunction(copyAll(cc, vm, args())));

}

 

@Override

public void toString(final QueryString qs) {

qs.token("test-function").params(exprs);

}

}

}

 

Best regards
Gunther

 

Gesendet: Freitag, 15. November 2024 um 14:36

Von: "Nico Verwer (Rakensi)" <nver...@rakensi.com>

An: basex-talk@mailman.uni-konstanz.de

Betreff: [basex-talk] Question: trying to make a higher-order function in a Java module

This is a long question, and quite complicated, at least to me.

I am trying to make a Java module, which is included in BaseX as a jar-file in `lib/custom`.
The module contains one XQuery function:

named-entity-recognition($grammar as item(), $options as map(*)?) as function(item()) as node()*

This is a higher-order XQuery function that returns another (anonymous) XQuery function. The returned function is a parser (for named entities), similar to what the `invisible-xml` function returns.

The relevant part (I think) is the following Java function:

@Requires(Permission.NONE)

@Deterministic

@ContextDependent

public FuncItem namedEntityRecognition(Object grammar, Map<String, String> options) throws QueryException {

// Types of the arguments of the generated function.

final Var[] generatedFunctionParameters = { new VarScope().addNew(new QNm("input"), SeqType.ITEM_O, queryContext, null) };

// Type of the generated function.

final FuncType generatedFunctionType = FuncType.get(SeqType.NODE_ZM, generatedFunctionParameters[0].declType);

// The generated function.

NamedEntityRecognitionFunction nerf = new NamedEntityRecognitionFunction(grammar, options, generatedFunctionType, queryContext);

// Return a function item.

return new FuncItem(null, nerf, generatedFunctionParameters, AnnList.EMPTY, generatedFunctionType, generatedFunctionParameters.length, null);

}

The NamedEntityRecognitionFunction has a public Value value(final QueryContext qc) function that does the actual parsing. It starts by getting the value of its (only) parameter:

Value inputValue = arg(0).value(qc); // Java

The namedEntityRecognition function works fine when I use it like this (XQuery):

let $ner-parse := ner:named-entity-recognition($grammar, map{})
return $input => $ner-parse()

However, is does not work when the parsing function is put into a declared variable, like

declare variable $ner-parse as function(item()) as node()* := ner:named-entity-recognition($grammar,map{});
$input => $ner-parse()

In this case, the parameter value obtained by arg(0).value(qc) is null. When I debug this _expression_, it turns out that the parameter ($input) is not on the stack. The stack (which is qc.stack) is all nulls, and the begin and end indexes of the stack are both 0, meaning that the stack is empty..

This probably means that the query context of a local (let) variable is different from the query context of a global (declare) variable.
Maybe I need to indicate that the namedEntityRecognition function returns a higher order function (but how)?

The code for this can be found at https://github.com/nverwer/basex-ner-xar.

If anyone can shed some light on this, that would be very much appreciated.

Best regards,
Nico Verwer