eXist-db · joewiz · May 11, 2026 · May 11, 2026 · May 12, 2026
@@ -517,6 +517,37 @@ public boolean isCalledAs(final String localName) {
         return localName.equals(mySignature.getName().getLocalPart());
     }
 
+    /**
+     * Indicates whether this function's behaviour depends on the dynamic
+     * context (focus, current dateTime, default collation, static base URI,
+     * implicit timezone, ...).
+     * <p>
+     * Used by {@link FunctionFactory#wrap(XQueryContext, Function)} to decide
+     * whether the lifted wrapper around a built-in must forward the caller's
+     * focus into the wrapped body when the built-in is used as a function
+     * item -- e.g. when retrieved via {@code fn:function-lookup} or as a
+     * named function reference. F&amp;O 3.1 section 16.1.1 requires the
+     * static and dynamic context of the lookup site to form part of the
+     * closure of the returned function.
+     * <p>
+     * Default is {@code false}. Overridden to {@code true} in each
+     * context-dependent built-in (the 0-arg forms of {@code fn:position},
+     * {@code fn:last}, {@code fn:node-name}, {@code fn:string},
+     * {@code fn:data}, {@code fn:base-uri}, {@code fn:string-length},
+     * {@code fn:normalize-space}, {@code fn:has-children},
+     * {@code fn:document-uri}, {@code fn:nilled}; the focus-using forms of
+     * {@code fn:lang}, {@code fn:id}, {@code fn:idref},
+     * {@code fn:element-with-id}; and {@code fn:current-dateTime},
+     * {@code fn:current-date}, {@code fn:current-time},
+     * {@code fn:implicit-timezone}, {@code fn:default-collation},
+     * {@code fn:default-language}, {@code fn:static-base-uri}).
+     *
+     * @return {@code true} if this function depends on the dynamic context
+     */
+    public boolean isContextDependent() {
+        return false;
+    }
+
     @Override
     public int getDependencies() {
         return Dependency.CONTEXT_ITEM | Dependency.CONTEXT_SET;

@@ -508,6 +508,20 @@ public static FunctionCall wrap(XQueryContext context, Function call) throws XPa
                 newSignature.setArgumentTypes(newParamArray);
 
 		final UserDefinedFunction func = new UserDefinedFunction(context, newSignature);
+		// This wrapper exists to lift a built-in Function into a FunctionCall
+		// so that it can be used as a function item. Per F&O 3.1 section
+		// 16.1.1, the static and dynamic context of the call to
+		// fn:function-lookup -- and of named function references -- forms
+		// part of the closure of the returned function. When the wrapped
+		// built-in is itself context-dependent (fn:position#0,
+		// fn:node-name#0, fn:lang#1, fn:default-collation,
+		// fn:static-base-uri, ...), the wrapper must forward that captured
+		// focus into the body. Each Function subclass declares its own
+		// context-dependency via Function.isContextDependent(); the default
+		// is false, so non-context-dependent built-ins (fn:concat,
+		// fn:string-length#1, ...) and user-defined functions do not pay
+		// the propagation cost.
+		func.setPropagateContextToBody(call.isContextDependent());
 		for (final QName varName: variables) {
 			func.addVariable(varName);
 		}

@@ -83,6 +83,11 @@ public int getArgumentCount() {
         return function.getArgumentCount();
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return function.isContextDependent();
+    }
+
     @Override
     public QName getName() {
         return function.getName();

@@ -48,6 +48,18 @@ public class UserDefinedFunction extends Function implements Cloneable {
     private boolean hasBeenReset = false;
     private List<ClosureVariable> closureVariables = null;
 
+    // When true, propagate the caller's focus (context sequence + item) to the
+    // body. Set by FunctionFactory.wrap so that named-function-reference and
+    // fn:function-lookup wrappers around context-dependent built-ins
+    // (fn:node-name#0, fn:string#0, fn:position#0, fn:lang#1, ...) can see a
+    // focus. Plain user-defined functions are not supposed to depend on the
+    // caller's focus, so this flag stays false for them. See F&O 3.1 §16.1.1.
+    private boolean propagateContextToBody = false;
+
+    public void setPropagateContextToBody(final boolean propagateContextToBody) {
+        this.propagateContextToBody = propagateContextToBody;
+    }
+
     public UserDefinedFunction(XQueryContext context, FunctionSignature signature) {
         super(context, signature);
     }
@@ -155,7 +167,11 @@ public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathExc
                             ", got " + currentArguments[j].getItemCount());
                 }
             }
-            result = body.eval(null, null);
+            if (propagateContextToBody) {
+                result = body.eval(contextSequence, contextItem);
+            } else {
+                result = body.eval(null, null);
+            }
             return result;
         } finally {
             // restore the local variable stack

@@ -41,6 +41,11 @@ public FnDefaultLanguage(final XQueryContext context) {
         super(context, FS_DEFAULT_LANGUAGE);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return true;
+    }
+
     @Override
     public Sequence eval(final Sequence[] args, final Sequence contextSequence) throws XPathException {
 

@@ -51,6 +51,11 @@ public FnHasChildren(final XQueryContext context, final FunctionSignature signat
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, final Item contextItem) throws XPathException {
         final NodeValue node;

@@ -77,6 +77,15 @@ public FunBaseURI(XQueryContext context, FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        // 0-arg base-uri() reads the focus; static-base-uri() reads the
+        // call-site's static base URI from the XQueryContext. Both forms
+        // must close over the lookup-site context when wrapped via
+        // fn:function-lookup or a named function reference.
+        return isCalledAs(FS_STATIC_BASE_URI) || getArgumentCount() == 0;
+    }
+
     /* (non-Javadoc)
      * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[],
      * org.exist.xquery.value.Sequence)

@@ -82,6 +82,11 @@ public FunCurrentDateTime(XQueryContext context, FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return true;
+    }
+
     public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {
             context.getProfiler().start(this);

@@ -68,6 +68,11 @@ public FunData(XQueryContext context, FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     /* (non-Javadoc)
      * @see org.exist.xquery.Expression#eval(org.exist.xquery.value.Sequence,
      * org.exist.xquery.value.Item)

@@ -55,6 +55,11 @@ public FunDefaultCollation(XQueryContext context) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return true;
+    }
+
     public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
         if (context.getProfiler().isEnabled()) {
             context.getProfiler().start(this);

@@ -60,6 +60,11 @@ public FunDocumentURI(final XQueryContext context, final FunctionSignature signa
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(final Sequence contextSequence, final Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -59,6 +59,11 @@ public FunElementWithId(final XQueryContext context, final FunctionSignature sig
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 1;
+    }
+
     @Override
     public Sequence eval(final Sequence[] args, Sequence contextSequence) throws XPathException {
         if (getArgumentCount() < 1) {

@@ -50,6 +50,11 @@ public FunGenerateId(final XQueryContext context, final FunctionSignature signat
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(final Sequence[] args, final Sequence contextSequence) throws XPathException {
         final NodeValue node;

@@ -71,6 +71,11 @@ public FunId(XQueryContext context, FunctionSignature signature) {
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 1;
+    }
+
 	/**
 	 * @see org.exist.xquery.Expression#eval(Sequence, Item)
 	 */

@@ -92,6 +92,11 @@ public FunIdRef(XQueryContext context, FunctionSignature signature) {
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 1;
+    }
+
 	/**
 	 * @see org.exist.xquery.Expression#eval(Sequence, Item)
 	 */

@@ -54,6 +54,11 @@ public FunImplicitTimezone(XQueryContext context) {
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return true;
+    }
+
 	public Sequence eval(Sequence contextSequence, Item contextItem)
         throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -97,6 +97,11 @@ public FunLang(XQueryContext context, FunctionSignature signature) {
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 1;
+    }
+
 	public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
 		super.analyze(contextInfo);
 		try {

@@ -63,6 +63,11 @@ public int getDependencies() {
 			Dependency.CONTEXT_POSITION;
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return true;
+    }
+
 	/* (non-Javadoc)
 	 * @see org.exist.xquery.functions.Function#eval(org.exist.xquery.StaticContext, org.exist.dom.persistent.DocumentSet, org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
 	 */

@@ -90,6 +90,11 @@ public FunLocalName(final XQueryContext context, final FunctionSignature signatu
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, final Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -96,6 +96,11 @@ public FunName(final XQueryContext context, final FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, final Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -90,6 +90,11 @@ public FunNamespaceURI(final XQueryContext context, final FunctionSignature sign
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, final Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -58,6 +58,11 @@ public FunNilled(final XQueryContext context, final FunctionSignature signature)
 		super(context, signature);
 	}
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
 	@Override
 	public Sequence eval(final Sequence[] args, final Sequence contextSequence) throws XPathException {
 

@@ -73,6 +73,11 @@ public FunNodeName(final XQueryContext context, final FunctionSignature signatur
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, final Item contextItem) throws XPathException {
         if (context.getProfiler().isEnabled()) {

@@ -93,6 +93,11 @@ public FunNormalizeSpace(final XQueryContext context, final FunctionSignature si
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public int returnsType() {
         return Type.STRING;

@@ -97,6 +97,11 @@ public FunNumber(XQueryContext context, FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
         if(context.getProfiler().isEnabled()) {

@@ -94,7 +94,21 @@ public Sequence eval(Sequence[] args, Sequence contextSequence)
                     }
                     throw e;
                 }
-			    return call == null ? Sequence.EMPTY_SEQUENCE : new FunctionReference(this, call);
+			    if (call == null) {
+			        return Sequence.EMPTY_SEQUENCE;
+			    }
+			    final FunctionReference ref = new FunctionReference(this, call);
+			    // F&O 3.1 section 16.1.1: the static and dynamic context of the
+			    // call to fn:function-lookup forms part of the closure of the
+			    // returned function. Capture the focus so that context-dependent
+			    // built-ins (fn:position#0, fn:node-name#0, fn:lang#1, ...) run
+			    // against the focus that was in scope at the lookup site.
+			    final org.exist.xquery.value.Item capturedItem =
+			            (contextSequence != null && !contextSequence.isEmpty())
+			                    ? contextSequence.itemAt(0)
+			                    : null;
+			    ref.setCapturedContext(contextSequence, capturedItem);
+			    return ref;
 			} else if (isCalledAs("function-name")) {
 				final FunctionReference ref = (FunctionReference) args[0].itemAt(0);
 				final QName qname = ref.getSignature().getName();

@@ -55,6 +55,11 @@ public FunPath(final XQueryContext context, final FunctionSignature signature) {
         super(context, signature);
     }
 
+    @Override
+    public boolean isContextDependent() {
+        return getArgumentCount() == 0;
+    }
+
     @Override
     public Sequence eval(final Sequence[] args, final Sequence contextSequence) throws XPathException {
         final Sequence result;