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;
/* function lookup function and data */
void *funcLookupFunc; /* function lookup func */
void *funcLookupData; /* function lookup data */
/* temporary namespace lists kept for walking the namespace axis */
xmlNsPtr *tmpNsList; /* Array of namespaces */
int tmpNsNr; /* number of namespace in scope */
}; |
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
typedef xmlXPathContext *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 */
xmlNodePtr ancestor; /* used for walking preceding axis */
}; |
An XPath parser context, it contains pure parsing informations,
an xmlXPathContext, and the stack of objects.
>xmlXPathParserContextPtr
typedef xmlXPathParserContext *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; |
>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
typedef xmlNodeSet *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 xmlXPathObject *xmlXPathObjectPtr; |
>struct xmlXPathType
struct xmlXPathType {
const xmlChar *name; /* the type name */
xmlXPathConvertFunc func; /* the conversion function */
}; |
>xmlXPathTypePtr
typedef xmlXPathType *xmlXPathTypePtr; |
>struct xmlXPathVariable
struct xmlXPathVariable {
const xmlChar *name; /* the variable name */
xmlXPathObjectPtr value; /* the value */
}; |
>xmlXPathVariablePtr
typedef xmlXPathVariable *xmlXPathVariablePtr; |
>xmlXPathEvalFunc ()
an XPath evaluation function, the parameters are on the XPath context stack
>struct xmlXPathFunct
struct xmlXPathFunct {
const xmlChar *name; /* the function name */
xmlXPathEvalFunc func; /* the evaluation function */
}; |
>xmlXPathFuncPtr
typedef xmlXPathFunct *xmlXPathFuncPtr; |
>struct xmlXPathAxis
struct xmlXPathAxis {
const xmlChar *name; /* the axis name */
xmlXPathAxisFunc func; /* the search function */
}; |
>xmlXPathAxisPtr
typedef xmlXPathAxis *xmlXPathAxisPtr; |
>struct xmlXPathCompExpr
[14] Expr ::= OrExpr
[21] OrExpr ::= AndExpr
| OrExpr 'or' AndExpr
Parse and compile an expression
>xmlXPathCompExprPtr
typedef xmlXPathCompExpr *xmlXPathCompExprPtr; |
>xmlXPathFunction ()
An XPath function
The arguments (if any) are popped out of the context stack
and the result is pushed on the stack.
>xmlXPathIsNaN ()
int xmlXPathIsNaN (double val); |
Provides a portable isnan() function to detect whether a double
is a NotaNumber. Based on trio code
http://sourceforge.net/projects/ctrio/
>xmlXPathIsInf ()
int xmlXPathIsInf (double val); |
Provides a portable isinf() function to detect whether a double
is a +Infinite or -Infinite. Based on trio code
http://sourceforge.net/projects/ctrio/
>xmlXPathNodeSetGetLength()
#define xmlXPathNodeSetGetLength(ns) ((ns) ? (ns)->nodeNr : 0) |
Implement a functionality similar to the DOM NodeList.length
>xmlXPathNodeSetItem()
#define xmlXPathNodeSetItem(ns, index) |
Implements a functionality similar to the DOM NodeList.item()
>xmlXPathNodeSetIsEmpty()
#define xmlXPathNodeSetIsEmpty(ns) |
Checks whether ns is empty or not
>xmlXPathFreeObject ()
Free up an xmlXPathObjectPtr object.
>xmlXPathNodeSetCreate ()
Create a new xmlNodeSetPtr of type double and of value val
>xmlXPathFreeNodeSetList ()
Free up the xmlXPathObjectPtr obj but don't deallocate the objects in
the list contrary to xmlXPathFreeObject().
>xmlXPathFreeNodeSet ()
Free the NodeSet compound (not the actual nodes !).
>xmlXPathObjectCopy ()
allocate a new copy of a given object
>xmlXPathCmpNodes ()
Compare two nodes w.r.t document order
>xmlXPathCastNumberToBoolean ()
int xmlXPathCastNumberToBoolean (double val); |
Converts a number to its boolean value
>xmlXPathCastStringToBoolean ()
int xmlXPathCastStringToBoolean (const xmlChar *val); |
Converts a string to its boolean value
>xmlXPathCastNodeSetToBoolean ()
Converts a node-set to its boolean value
>xmlXPathCastToBoolean ()
Converts an XPath object to its boolean value
>xmlXPathCastBooleanToNumber ()
double xmlXPathCastBooleanToNumber (int val); |
Converts a boolean to its number value
>xmlXPathCastStringToNumber ()
double xmlXPathCastStringToNumber (const xmlChar *val); |
Converts a string to its number value
>xmlXPathCastNodeToNumber ()
double xmlXPathCastNodeToNumber (xmlNodePtr node); |
Converts a node to its number value
>xmlXPathCastNodeSetToNumber ()
Converts a node-set to its number value
>xmlXPathCastToNumber ()
Converts an XPath object to its number value
>xmlXPathCastBooleanToString ()
xmlChar* xmlXPathCastBooleanToString (int val); |
Converts a boolean to its string value.
>xmlXPathCastNumberToString ()
xmlChar* xmlXPathCastNumberToString (double val); |
Converts a number to its string value.
>xmlXPathCastNodeToString ()
Converts a node to its string value.
>xmlXPathCastNodeSetToString ()
Converts a node-set to its string value.
>xmlXPathCastToString ()
Converts an existing object to its string() equivalent
>xmlXPathConvertBoolean ()
Converts an existing object to its boolean() equivalent
>xmlXPathConvertNumber ()
Converts an existing object to its number() equivalent
>xmlXPathConvertString ()
Converts an existing object to its string() equivalent
>xmlXPathInit ()
void xmlXPathInit (void); |
Initialize the XPath environment
>xmlXPathNewContext ()
Create a new xmlXPathContext
>xmlXPathFreeContext ()
Free up an xmlXPathContext
>xmlXPathEval ()
Evaluate the XPath Location Path in the given context.
>xmlXPathEvalExpression ()
Evaluate the XPath expression in the given context.
>xmlXPathEvalPredicate ()
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.
>xmlXPathCompile ()
Compile an XPath expression
>xmlXPathCompiledEval ()
Evaluate the Precompiled XPath expression in the given context.
>xmlXPathFreeCompExpr ()
Free up the memory allocated by comp