added implementation of SAXON expression(), eval() and evaluate()

	* libexslt/saxon.c libexslt/Makefile.am libexslt/exslt.[ch]:
	  added implementation of SAXON expression(), eval() and
	  evaluate() functions.
	  See http://saxon.sourceforge.net/saxon6.4.4/extensions.html
	* tests/extension/evaluate.xsl tests/extension/list.{xsl,out}:
	  modified to use SAXON namespace (functions are not registered
	  in the LibXSLT namespace)
	* tests/exslt/common/object-type.1.out: modified to take account
	  of the new saxon:expression function

1 files changed, 186 insertions, 0 deletions

diff --git a/libexslt/saxon.c b/libexslt/saxon.c
new file mode 100644
index 00000000..2a8325e6
--- /dev/null
+++ b/libexslt/saxon.c
@@ -0,0 +1,186 @@
+#include <libxml/tree.h>
+#include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
+#include <libxml/parser.h>
+
+#include <libxslt/xsltconfig.h>
+#include <libxslt/xsltutils.h>
+#include <libxslt/xsltInternals.h>
+#include <libxslt/extensions.h>
+
+#include "exslt.h"
+
+/**
+ * exsltSaxonInit:
+ * @ctxt: an XSLT transformation context
+ * @URI: the namespace URI for the extension
+ *
+ * Initializes the SAXON module.
+ *
+ * Returns the data for this transformation
+ */
+static xmlHashTablePtr
+exsltSaxonInit (xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED,
+		const xmlChar *URI ATTRIBUTE_UNUSED) {
+    return xmlHashCreate(1);
+}
+
+/**
+ * exsltSaxonShutdown:
+ * @ctxt: an XSLT transformation context
+ * @URI: the namespace URI for the extension
+ * @data: the module data to free up
+ *
+ * Shutdown the SAXON extension module
+ */
+static void
+exsltSaxonShutdown (xsltTransformContextPtr ctxt ATTRIBUTE_UNUSED,
+		    const xmlChar *URI ATTRIBUTE_UNUSED,
+		    xmlHashTablePtr data) {
+    xmlHashFree(data, (xmlHashDeallocator) xmlXPathFreeCompExpr);
+}
+
+
+/**
+ * exsltSaxonExpressionFunction:
+ * @ctxt: an XPath parser context
+ * @nargs: the number of arguments
+ *
+ * The supplied string must contain an XPath expression. The result of
+ * the function is a stored expression, which may be supplied as an
+ * argument to other extension functions such as saxon:eval(),
+ * saxon:sum() and saxon:distinct(). The result of the expression will
+ * usually depend on the current node. The expression may contain
+ * references to variables that are in scope at the point where
+ * saxon:expression() is called: these variables will be replaced in
+ * the stored expression with the values they take at the time
+ * saxon:expression() is called, not the values of the variables at
+ * the time the stored expression is evaluated.  Similarly, if the
+ * expression contains namespace prefixes, these are interpreted in
+ * terms of the namespace declarations in scope at the point where the
+ * saxon:expression() function is called, not those in scope where the
+ * stored expression is evaluated.
+ *
+ * TODO: current implementation doesn't conform to SAXON behaviour
+ * regarding context and namespaces.
+ */
+static void
+exsltSaxonExpressionFunction (xmlXPathParserContextPtr ctxt, int nargs) {
+    xmlChar *arg;
+    xmlXPathCompExprPtr ret;
+    xmlHashTablePtr hash;
+    xsltTransformContextPtr tctxt = xsltXPathGetTransformContext(ctxt);
+
+    if (nargs != 1) {
+	xmlXPathSetArityError(ctxt);
+	return;
+    }
+
+    arg = xmlXPathPopString(ctxt);
+    if (xmlXPathCheckError(ctxt) || (arg == NULL)) {
+	xmlXPathSetTypeError(ctxt);
+	return;
+    }
+
+    hash = (xmlHashTablePtr) xsltGetExtData(tctxt->style,
+					    ctxt->context->functionURI);
+
+    ret = xmlHashLookup(hash, arg);
+    if (ret != NULL)
+	goto done;
+
+    ret = xmlXPathCompile(arg);
+
+    xmlHashAddEntry(hash, arg, (void *) ret);
+
+done:
+    xmlFree(arg);
+
+    xmlXPathReturnExternal(ctxt, ret);
+}
+
+/**
+ * exsltSaxonEvalFunction:
+ * @ctxt:  an XPath parser context
+ * @nargs:  number of arguments
+ *
+ * Implements de SAXON eval() function:
+ *    object saxon:eval (saxon:stored-expression)
+ * Returns the result of evaluating the supplied stored expression.
+ * A stored expression may be obtained as the result of calling
+ * the saxon:expression() function.
+ * The stored expression is evaluated in the current context, that
+ * is, the context node is the current node, and the context position
+ * and context size are the same as the result of calling position()
+ * or last() respectively.
+ */
+static void
+exsltSaxonEvalFunction (xmlXPathParserContextPtr ctxt, int nargs) {
+     xmlXPathCompExprPtr expr;
+     xmlXPathObjectPtr ret;
+
+     if (nargs != 1) {
+	  xmlXPathSetArityError(ctxt);
+	  return;
+     }
+
+     if (!xmlXPathStackIsExternal(ctxt)) {
+	  xmlXPathSetTypeError(ctxt);
+	  return;
+     }
+
+     expr = (xmlXPathCompExprPtr) xmlXPathPopExternal(ctxt);
+
+     ret = xmlXPathCompiledEval(expr, ctxt->context);
+
+     valuePush(ctxt, ret);
+}
+
+/**
+ * exsltSaxonEvaluateFunction:
+ * @ctxt:  an XPath parser context
+ * @nargs: number of arguments
+ *
+ * Implements the SAXON evaluate() function
+ *     object saxon:evaluate (string)
+ * The supplied string must contain an XPath expression. The result of
+ * the function is the result of evaluating the XPath expression. This
+ * is useful where an expression needs to be constructed at run-time or
+ * passed to the stylesheet as a parameter, for example where the sort
+ * key is determined dynamically. The context for the expression (e.g.
+ * which variables and namespaces are available) is exactly the same as
+ * if the expression were written explicitly at this point in the
+ * stylesheet. The function saxon:evaluate(string) is shorthand for
+ * saxon:eval(saxon:expression(string)).
+ */
+static void
+exsltSaxonEvaluateFunction (xmlXPathParserContextPtr ctxt, int nargs) {
+     if (nargs != 1) {
+	  xmlXPathSetArityError(ctxt);
+	  return;
+     }
+
+     exsltSaxonExpressionFunction(ctxt, 1);
+     exsltSaxonEvalFunction(ctxt, 1);
+}
+
+/**
+ * exsltSaxonRegister:
+ *
+ * Registers the SAXON extension module
+ */
+void
+exsltSaxonRegister (void) {
+     xsltRegisterExtModule (SAXON_NAMESPACE,
+			    (xsltExtInitFunction) exsltSaxonInit,
+			    (xsltExtShutdownFunction) exsltSaxonShutdown);
+     xsltRegisterExtModuleFunction((const xmlChar *) "expression",
+				   SAXON_NAMESPACE,
+				   exsltSaxonExpressionFunction);
+     xsltRegisterExtModuleFunction((const xmlChar *) "eval",
+				   SAXON_NAMESPACE,
+				   exsltSaxonEvalFunction);
+     xsltRegisterExtModuleFunction((const xmlChar *) "evaluate",
+				   SAXON_NAMESPACE,
+				   exsltSaxonEvaluateFunction);
+}