12 Package XPath APIs for C

XPath methods process XPath related types and interfaces.

This chapter contains this section:

XPath Interface

See Also:

XPath Interface

Table 12-1 summarizes the methods available through the XPath interface.

Table 12-1 Summary of XPath Methods

Function	Summary
XmlXPathCreateCtx()	Create an XPath context.
XmlXPathDestroyCtx()	Destroy an XPath context.
XmlXPathEval()	Evaluate XPath expression.
XmlXPathGetObjectBoolean()	Get boolean value of XPath object.
XmlXPathGetObjectFragment()	Get fragment value of XPath object.
XmlXPathGetObjectNSetNode()	Get node from nodeset type XPath object.
XmlXPathGetObjectNSetNum()	Get number of nodes in nodeset type XPath object.
XmlXPathGetObjectNumber()	Get number from XPath object.
XmlXPathGetObjectString()	Get string from XPath object.
XmlXPathGetObjectType()	Get XPath object type.
XmlXPathParse()	Parse XPath expression.

XmlXPathCreateCtx()

Create an XPath context

Syntax

xpctx* XmlXPathCreateCtx(
   xmlctx *xsl,
   oratext *baseuri,
   xmlnode *ctxnode, 
   ub4 ctxpos, 
   ub4 ctxsize);

Parameter	In/Out	Description
xsl	IN	XSL stylesheet as `xmldoc` object
baseuri	IN	base URI used by document, if any
ctxnode	IN	current context position
ctxpos	IN	current context size
ctxsize	IN	current context node

Returns

(xpctx *) XPath context or NULL on error

XmlXPathDestroyCtx()

Destroy an XPath context.

Syntax

void XmlXPathDestroyCtx(
   xpctx *xslxpctx);

Parameter	In/Out	Description
xslxpctx	IN	XPath context object

XmlXPathEval()

Evaluate XPath expression.

Syntax

xpobj *XmlXPathEval(
   xpctx *xctx, 
   xpexpr *exprtree, 
   xmlerr *err);

Parameter	In/Out	Description
xctx	IN	`XPath` context
exprtree	IN	parsed `XPath` expression tree
err	OUT	error code

Returns

(xpobj *) result XPath object or NULL on error

XmlXPathGetObjectBoolean()

Get boolean value of XPath object

Syntax

boolean XmlXPathGetObjectBoolean(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	XPath object

Returns

(boolean) truth value

XmlXPathGetObjectFragment()

Get boolean value of XPath object

Syntax

xmlnode* XmlXPathGetObjectFragment(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	`XPath` object

Returns

(boolean) truth value

XmlXPathGetObjectNSetNode()

Get node from nodeset-type XPath object

Syntax

xmlnode *XmlXPathGetObjectNSetNode(
   xpobj *obj,
   ub4 i);

Parameter	In/Out	Description
obj	IN	`XPath` object
i	IN	node index in nodeset

Returns

(xmlnode *) The object type or values.

XmlXPathGetObjectNSetNum()

Get number of nodes in nodeset-type XPath object

Syntax

ub4 XmlXPathGetObjectNSetNum(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	`XPath` object

Returns

(ub4) number of nodes in nodeset

XmlXPathGetObjectNumber()

Get number from XPath object

Syntax

double XmlXPathGetObjectNumber(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	`XPath` object

Returns

(double) number

XmlXPathGetObjectString()

Get string from XPath object

Syntax

oratext *XmlXPathGetObjectString(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	XPath object

Returns

(oratext *) string

XmlXPathGetObjectType()

Get XPath object type

Syntax

xmlxslobjtype XmlXPathGetObjectType(
   xpobj *obj);

Parameter	In/Out	Description
obj	IN	XPath object

Returns

(xmlxslobjtype) type-code for object

XmlXPathParse()

Parse XPath expression.

Syntax

xpexpr* XmlXPathParse(
   xpctx *xctx,
   oratext *expr,
   xmlerr * err);

Parameter	In/Out	Description
xctx	IN	XPath context object
expr	IN	XPath expression
err	OUT	error code

Returns

(xpexpr *) XPath expression parse tree or NULL on error