Gnome XML Library Reference Manual
<<< Previous PageHomeUpNext Page >>>

xpath

Name

xpath -- 

Synopsis



struct      xmlXPathContext;
typedef     xmlXPathContextPtr;
struct      xmlXPathParserContext;
typedef     xmlXPathParserContextPtr;
enum        xmlXPathError;
struct      xmlNodeSet;
typedef     xmlNodeSetPtr;
enum        xmlXPathObjectType;
struct      xmlXPathObject;
typedef     xmlXPathObjectPtr               ();
int         (*xmlXPathConvertFunc)          (xmlXPathObjectPtr obj,
                                             int type);
struct      xmlXPathType;
typedef     xmlXPathTypePtr;
struct      xmlXPathVariable;
typedef     xmlXPathVariablePtr;
void        (*xmlXPathEvalFunc)             (xmlXPathParserContextPtr ctxt,
                                             int nargs);
struct      xmlXPathFunct;
typedef     xmlXPathFuncPtr;
xmlXPathObjectPtr (*xmlXPathAxisFunc)       (xmlXPathParserContextPtr ctxt,
                                             xmlXPathObjectPtr cur);
struct      xmlXPathAxis;
typedef     xmlXPathAxisPtr;
struct      xmlXPathCompExpr;
typedef     xmlXPathCompExprPtr;
void        (*xmlXPathFunction)             (xmlXPathParserContextPtr ctxt,
                                             int nargs);
#define     xmlXPathNodeSetGetLength        (ns)
#define     xmlXPathNodeSetItem             (ns, index)
void        xmlXPathFreeObject              (xmlXPathObjectPtr obj);
xmlNodeSetPtr xmlXPathNodeSetCreate         (xmlNodePtr val);
void        xmlXPathFreeNodeSetList         (xmlXPathObjectPtr obj);
void        xmlXPathFreeNodeSet             (xmlNodeSetPtr obj);
xmlXPathObjectPtr xmlXPathObjectCopy        (xmlXPathObjectPtr val);
int         xmlXPathCmpNodes                (xmlNodePtr node1,
                                             xmlNodePtr node2);
int         xmlXPathCastNumberToBoolean     (double val);
int         xmlXPathCastStringToBoolean     (const xmlChar *val);
int         xmlXPathCastNodeSetToBoolean    (xmlNodeSetPtr ns);
int         xmlXPathCastToBoolean           (xmlXPathObjectPtr val);
double      xmlXPathCastBooleanToNumber     (int val);
double      xmlXPathCastStringToNumber      (const xmlChar *val);
double      xmlXPathCastNodeToNumber        (xmlNodePtr node);
double      xmlXPathCastNodeSetToNumber     (xmlNodeSetPtr ns);
double      xmlXPathCastToNumber            (xmlXPathObjectPtr val);
xmlChar*    xmlXPathCastBooleanToString     (int val);
xmlChar*    xmlXPathCastNumberToString      (double val);
xmlChar*    xmlXPathCastNodeToString        (xmlNodePtr node);
xmlChar*    xmlXPathCastNodeSetToString     (xmlNodeSetPtr ns);
xmlChar*    xmlXPathCastToString            (xmlXPathObjectPtr val);
xmlXPathObjectPtr xmlXPathConvertBoolean    (xmlXPathObjectPtr val);
xmlXPathObjectPtr xmlXPathConvertNumber     (xmlXPathObjectPtr val);
xmlXPathObjectPtr xmlXPathConvertString     (xmlXPathObjectPtr val);
void        xmlXPathInit                    (void);
xmlXPathContextPtr xmlXPathNewContext       (xmlDocPtr doc);
void        xmlXPathFreeContext             (xmlXPathContextPtr ctxt);
xmlXPathObjectPtr xmlXPathEval              (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);
xmlXPathObjectPtr xmlXPathEvalXPtrExpr      (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);
xmlXPathObjectPtr xmlXPathEvalExpression    (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);
int         xmlXPathEvalPredicate           (xmlXPathContextPtr ctxt,
                                             xmlXPathObjectPtr res);
xmlXPathCompExprPtr xmlXPathCompile         (const xmlChar *str);
xmlXPathObjectPtr xmlXPathCompiledEval      (xmlXPathCompExprPtr comp,
                                             xmlXPathContextPtr ctx);
void        xmlXPathFreeCompExpr            (xmlXPathCompExprPtr comp);

Description

Details

struct xmlXPathContext

struct xmlXPathContext {
    xmlDocPtr doc;			/* The current document */
    xmlNodePtr node;			/* The current node */

    int nb_variables_unused;		/* unused (hash table) */
    int max_variables_unused;		/* unused (hash table) */
    xmlHashTablePtr varHash;		/* Hash table of defined variables */

    int nb_types;			/* number of defined types */
    int max_types;			/* max number of types */
    xmlXPathTypePtr types;		/* Array of defined types */

    int nb_funcs_unused;		/* unused (hash table) */
    int max_funcs_unused;		/* unused (hash table) */
    xmlHashTablePtr funcHash;		/* Hash table of defined funcs */

    int nb_axis;			/* number of defined axis */
    int max_axis;			/* max number of axis */
    xmlXPathAxisPtr axis;		/* Array of defined axis */

    /* the namespace nodes of the context node */
    xmlNsPtr *namespaces;		/* Array of namespaces */
    int nsNr;				/* number of namespace in scope */
    void *user;				/* function to free */

    /* extra variables */
    int contextSize;			/* the context size */
    int proximityPosition;		/* the proximity position */

    /* extra stuff for XPointer */
    int xptr;				/* it this an XPointer context */
    xmlNodePtr here;			/* for here() */
    xmlNodePtr origin;			/* for origin() */

    /* the set of namespace declarations in scope for the expression */
    xmlHashTablePtr nsHash;		/* The namespaces hash table */
    void *varLookupFunc;		/* variable lookup func */
    void *varLookupData;		/* variable lookup data */

    /* Possibility to link in an extra item */
    void *extra;                        /* needed for XSLT */

    /* The function name and URI when calling a function */
    const xmlChar *function;
    const xmlChar *functionURI;
};

Expression evaluation occurs with respect to a context. he context consists of: - a node (the context node) - a node list (the context node list) - a set of variable bindings - a function library - the set of namespace declarations in scope for the expression Following the switch to hash tables, this need to be trimmed up at the next binary incompatible release.

xmlXPathContextPtr

struct xmlXPathParserContext

struct xmlXPathParserContext {
    const xmlChar *cur;			/* the current char being parsed */
    const xmlChar *base;			/* the full expression */

    int error;				/* error code */

    xmlXPathContextPtr  context;	/* the evaluation context */
    xmlXPathObjectPtr     value;	/* the current value */
    int                 valueNr;	/* number of values stacked */
    int                valueMax;	/* max number of values stacked */
    xmlXPathObjectPtr *valueTab;	/* stack of values */

    xmlXPathCompExprPtr comp;		/* the precompiled expression */
    int xptr;				/* it this an XPointer expression */
};

An XPath parser context, it contains pure parsing informations, an xmlXPathContext, and the stack of objects.

xmlXPathParserContextPtr

enum xmlXPathError

typedef enum {
    XPATH_EXPRESSION_OK = 0,
    XPATH_NUMBER_ERROR,
    XPATH_UNFINISHED_LITERAL_ERROR,
    XPATH_START_LITERAL_ERROR,
    XPATH_VARIABLE_REF_ERROR,
    XPATH_UNDEF_VARIABLE_ERROR,
    XPATH_INVALID_PREDICATE_ERROR,
    XPATH_EXPR_ERROR,
    XPATH_UNCLOSED_ERROR,
    XPATH_UNKNOWN_FUNC_ERROR,
    XPATH_INVALID_OPERAND,
    XPATH_INVALID_TYPE,
    XPATH_INVALID_ARITY,
    XPATH_INVALID_CTXT_SIZE,
    XPATH_INVALID_CTXT_POSITION,
    XPATH_MEMORY_ERROR,
    XPTR_SYNTAX_ERROR,
    XPTR_RESOURCE_ERROR,
    XPTR_SUB_RESOURCE_ERROR,
    XPATH_UNDEF_PREFIX_ERROR,
    XPATH_ENCODING_ERROR,
    XPATH_INVALID_CHAR_ERROR
} xmlXPathError;

Create a new xmlNodeSetPtr of type double and of value val

struct xmlNodeSet

struct xmlNodeSet {
    int nodeNr;			/* number of nodes in the set */
    int nodeMax;		/* size of the array as allocated */
    xmlNodePtr *nodeTab;	/* array of nodes in no particular order */
};

xmlNodeSetPtr

enum xmlXPathObjectType

typedef enum {
    XPATH_UNDEFINED = 0,
    XPATH_NODESET = 1,
    XPATH_BOOLEAN = 2,
    XPATH_NUMBER = 3,
    XPATH_STRING = 4,
    XPATH_POINT = 5,
    XPATH_RANGE = 6,
    XPATH_LOCATIONSET = 7,
    XPATH_USERS = 8,
    XPATH_XSLT_TREE = 9  /* An XSLT value tree, non modifiable */
} xmlXPathObjectType;

struct xmlXPathObject

struct xmlXPathObject {
    xmlXPathObjectType type;
    xmlNodeSetPtr nodesetval;
    int boolval;
    double floatval;
    xmlChar *stringval;
    void *user;
    int index;
    void *user2;
    int index2;
};

xmlXPathObjectPtr ()

typedef     xmlXPathObjectPtr               ();

Returns : 

xmlXPathConvertFunc ()

int         (*xmlXPathConvertFunc)          (xmlXPathObjectPtr obj,
                                             int type);

obj : 
type : 
Returns : 

struct xmlXPathType

struct xmlXPathType {
    const xmlChar         *name;		/* the type name */
    xmlXPathConvertFunc func;		/* the conversion function */
};

xmlXPathTypePtr

struct xmlXPathVariable

struct xmlXPathVariable {
    const xmlChar       *name;		/* the variable name */
    xmlXPathObjectPtr value;		/* the value */
};

xmlXPathVariablePtr

xmlXPathEvalFunc ()

void        (*xmlXPathEvalFunc)             (xmlXPathParserContextPtr ctxt,
                                             int nargs);

ctxt : 
nargs : 

struct xmlXPathFunct

struct xmlXPathFunct {
    const xmlChar      *name;		/* the function name */
    xmlXPathEvalFunc func;		/* the evaluation function */
};

xmlXPathFuncPtr

xmlXPathAxisFunc ()

xmlXPathObjectPtr (*xmlXPathAxisFunc)       (xmlXPathParserContextPtr ctxt,
                                             xmlXPathObjectPtr cur);

ctxt : 
cur : 
Returns : 

struct xmlXPathAxis

struct xmlXPathAxis {
    const xmlChar      *name;		/* the axis name */
    xmlXPathAxisFunc func;		/* the search function */
};

xmlXPathAxisPtr

struct xmlXPathCompExpr

struct xmlXPathCompExpr;

[14] Expr ::= OrExpr [21] OrExpr ::= AndExpr | OrExpr 'or' AndExpr

Parse and compile an expression

xmlXPathCompExprPtr

xmlXPathFunction ()

void        (*xmlXPathFunction)             (xmlXPathParserContextPtr ctxt,
                                             int nargs);

An XPath function The arguments (if any) are popped out of the context stack and the result is pushed on the stack.

ctxt : 
nargs : 

xmlXPathNodeSetGetLength()

#define     xmlXPathNodeSetGetLength(ns)

ns : 

xmlXPathNodeSetItem()

#define     xmlXPathNodeSetItem(ns, index)

ns : 
index : 

xmlXPathFreeObject ()

void        xmlXPathFreeObject              (xmlXPathObjectPtr obj);

Free up an xmlXPathObjectPtr object.

obj : 

xmlXPathNodeSetCreate ()

xmlNodeSetPtr xmlXPathNodeSetCreate         (xmlNodePtr val);

Create a new xmlNodeSetPtr of type double and of value val

val : 
Returns : 

xmlXPathFreeNodeSetList ()

void        xmlXPathFreeNodeSetList         (xmlXPathObjectPtr obj);

Free up the xmlXPathObjectPtr obj but don't deallocate the objects in the list contrary to xmlXPathFreeObject().

obj : 

xmlXPathFreeNodeSet ()

void        xmlXPathFreeNodeSet             (xmlNodeSetPtr obj);

Free the NodeSet compound (not the actual nodes !).

obj : 

xmlXPathObjectCopy ()

xmlXPathObjectPtr xmlXPathObjectCopy        (xmlXPathObjectPtr val);

allocate a new copy of a given object

val : 
Returns : 

xmlXPathCmpNodes ()

int         xmlXPathCmpNodes                (xmlNodePtr node1,
                                             xmlNodePtr node2);

Compare two nodes w.r.t document order

node1 : 
node2 : 
Returns : 

xmlXPathCastNumberToBoolean ()

int         xmlXPathCastNumberToBoolean     (double val);

Converts a number to its boolean value

val : 
Returns : 

xmlXPathCastStringToBoolean ()

int         xmlXPathCastStringToBoolean     (const xmlChar *val);

Converts a string to its boolean value

val : 
Returns : 

xmlXPathCastNodeSetToBoolean ()

int         xmlXPathCastNodeSetToBoolean    (xmlNodeSetPtr ns);

Converts a node-set to its boolean value

ns : 
Returns : 

xmlXPathCastToBoolean ()

int         xmlXPathCastToBoolean           (xmlXPathObjectPtr val);

val : 
Returns : 

xmlXPathCastBooleanToNumber ()

double      xmlXPathCastBooleanToNumber     (int val);

Converts a boolean to its number value

val : 
Returns : 

xmlXPathCastStringToNumber ()

double      xmlXPathCastStringToNumber      (const xmlChar *val);

Converts a string to its number value

val : 
Returns : 

xmlXPathCastNodeToNumber ()

double      xmlXPathCastNodeToNumber        (xmlNodePtr node);

Converts a node to its number value

node : 
Returns : 

xmlXPathCastNodeSetToNumber ()

double      xmlXPathCastNodeSetToNumber     (xmlNodeSetPtr ns);

Converts a node-set to its number value

ns : 
Returns : 

xmlXPathCastToNumber ()

double      xmlXPathCastToNumber            (xmlXPathObjectPtr val);

Converts an XPath object to its number value

val : 
Returns : 

xmlXPathCastBooleanToString ()

xmlChar*    xmlXPathCastBooleanToString     (int val);

Converts a boolean to its string value.

val : 
Returns : 

xmlXPathCastNumberToString ()

xmlChar*    xmlXPathCastNumberToString      (double val);

Converts a number to its string value.

val : 
Returns : 

xmlXPathCastNodeToString ()

xmlChar*    xmlXPathCastNodeToString        (xmlNodePtr node);

Converts a node to its string value.

node : 
Returns : 

xmlXPathCastNodeSetToString ()

xmlChar*    xmlXPathCastNodeSetToString     (xmlNodeSetPtr ns);

Converts a node-set to its string value.

ns : 
Returns : 

xmlXPathCastToString ()

xmlChar*    xmlXPathCastToString            (xmlXPathObjectPtr val);

Converts an existing object to its string() equivalent

val : 
Returns : 

xmlXPathConvertBoolean ()

xmlXPathObjectPtr xmlXPathConvertBoolean    (xmlXPathObjectPtr val);

Converts an existing object to its boolean() equivalent

val : 
Returns : 

xmlXPathConvertNumber ()

xmlXPathObjectPtr xmlXPathConvertNumber     (xmlXPathObjectPtr val);

Converts an existing object to its number() equivalent

val : 
Returns : 

xmlXPathConvertString ()

xmlXPathObjectPtr xmlXPathConvertString     (xmlXPathObjectPtr val);

Converts an existing object to its string() equivalent

val : 
Returns : 

xmlXPathInit ()

void        xmlXPathInit                    (void);

Initialize the XPath environment

xmlXPathNewContext ()

xmlXPathContextPtr xmlXPathNewContext       (xmlDocPtr doc);

Create a new xmlXPathContext

doc : 
Returns : 

xmlXPathFreeContext ()

void        xmlXPathFreeContext             (xmlXPathContextPtr ctxt);

Free up an xmlXPathContext

ctxt : 

xmlXPathEval ()

xmlXPathObjectPtr xmlXPathEval              (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);

Evaluate the XPath Location Path in the given context.

str : 
ctxt : 
Returns : 

xmlXPathEvalXPtrExpr ()

xmlXPathObjectPtr xmlXPathEvalXPtrExpr      (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);

str : 
ctxt : 
Returns : 

xmlXPathEvalExpression ()

xmlXPathObjectPtr xmlXPathEvalExpression    (const xmlChar *str,
                                             xmlXPathContextPtr ctxt);

Evaluate the XPath expression in the given context.

str : 
ctxt : 
Returns : 

xmlXPathEvalPredicate ()

int         xmlXPathEvalPredicate           (xmlXPathContextPtr ctxt,
                                             xmlXPathObjectPtr res);

Evaluate a predicate result for the current node. A PredicateExpr is evaluated by evaluating the Expr and converting the result to a boolean. If the result is a number, the result will be converted to true if the number is equal to the position of the context node in the context node list (as returned by the position function) and will be converted to false otherwise; if the result is not a number, then the result will be converted as if by a call to the boolean function.

Return 1 if predicate is true, 0 otherwise

ctxt : 
res : 
Returns : 

xmlXPathCompile ()

xmlXPathCompExprPtr xmlXPathCompile         (const xmlChar *str);

Compile an XPath expression

str : 
Returns : 

xmlXPathCompiledEval ()

xmlXPathObjectPtr xmlXPathCompiledEval      (xmlXPathCompExprPtr comp,
                                             xmlXPathContextPtr ctx);

Evaluate the Precompiled XPath expression in the given context.

comp : 
ctx : 
Returns : 

xmlXPathFreeCompExpr ()

void        xmlXPathFreeCompExpr            (xmlXPathCompExprPtr comp);

Free up the memory allocated by comp

comp : 



<<< Previous PageHomeUpNext Page >>>
HTMLtreexpathInternals