# ## Module pattern from libxml2

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allows to compile and test pattern expressions for nodes either in a tree or based on a parser state. ## Table of Contents
    Structure xmlPattern
    struct _xmlPattern
    The content of this structure is not made public by the API.
    Enum xmlPatternFlags
    Typedef xmlPattern * xmlPatternPtr
    Structure xmlStreamCtxt
    struct _xmlStreamCtxt
    The content of this structure is not made public by the API.
    Typedef xmlStreamCtxt * xmlStreamCtxtPtr
    void	xmlFreePattern			(xmlPatternPtr comp)
    void	xmlFreePatternList		(xmlPatternPtr comp)
    void	xmlFreeStreamCtxt		(xmlStreamCtxtPtr stream)
    int	xmlPatternFromRoot		(xmlPatternPtr comp)
    xmlStreamCtxtPtr	xmlPatternGetStreamCtxt	(xmlPatternPtr comp)
    int	xmlPatternMatch			(xmlPatternPtr comp,
    					 xmlNodePtr node)
    int	xmlPatternMaxDepth		(xmlPatternPtr comp)
    int	xmlPatternMinDepth		(xmlPatternPtr comp)
    int	xmlPatternStreamable		(xmlPatternPtr comp)
    xmlPatternPtr	xmlPatterncompile	(const xmlChar * pattern,
    					 xmlDict * dict,
    					 int flags,
    					 const xmlChar ** namespaces)
    int	xmlStreamPop			(xmlStreamCtxtPtr stream)
    int	xmlStreamPush			(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns)
    int	xmlStreamPushAttr		(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns)
    int	xmlStreamPushNode		(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns,
    					 int nodeType)
    int	xmlStreamWantsAnyNode		(xmlStreamCtxtPtr streamCtxt)
## Description ### Structure xmlPattern
    Structure xmlPattern
    struct _xmlPattern {
    The content of this structure is not made public by the API.
    }
### Enum xmlPatternFlags
    Enum xmlPatternFlags {
        XML_PATTERN_DEFAULT = 0 : simple pattern match
        XML_PATTERN_XPATH = 1 : standard XPath pattern
        XML_PATTERN_XSSEL = 2 : XPath subset for schema selector
        XML_PATTERN_XSFIELD = 4 : XPath subset for schema field
    }
### Structure xmlStreamCtxt
    Structure xmlStreamCtxt
    struct _xmlStreamCtxt {
    The content of this structure is not made public by the API.
    }
### Function: xmlFreePattern
    void	xmlFreePattern			(xmlPatternPtr comp)
Free up the memory allocated by @comp
`comp`: | an XSLT comp
### Function: xmlFreePatternList
    void	xmlFreePatternList		(xmlPatternPtr comp)
Free up the memory allocated by all the elements of @comp
`comp`: | an XSLT comp list
### Function: xmlFreeStreamCtxt
    void	xmlFreeStreamCtxt		(xmlStreamCtxtPtr stream)
Free the stream context
`stream`: | the stream context
### Function: xmlPatternFromRoot
    int	xmlPatternFromRoot		(xmlPatternPtr comp)
Check if the pattern must be looked at from the root.
`comp`: | the precompiled pattern
`Returns`: | 1 if true, 0 if false and -1 in case of error
### Function: xmlPatternGetStreamCtxt
    xmlStreamCtxtPtr	xmlPatternGetStreamCtxt	(xmlPatternPtr comp)
Get a streaming context for that pattern Use xmlFreeStreamCtxt to free the context.
`comp`: | the precompiled pattern
`Returns`: | a pointer to the context or NULL in case of failure
### Function: xmlPatternMatch
    int	xmlPatternMatch			(xmlPatternPtr comp,
    					 xmlNodePtr node)
Test whether the node matches the pattern
`comp`: | the precompiled pattern
`node`: | a node
`Returns`: | 1 if it matches, 0 if it doesn't and -1 in case of failure
### Function: xmlPatternMaxDepth
    int	xmlPatternMaxDepth		(xmlPatternPtr comp)
Check the maximum depth reachable by a pattern
`comp`: | the precompiled pattern
`Returns`: | -2 if no limit (using //), otherwise the depth, and -1 in case of error
### Function: xmlPatternMinDepth
    int	xmlPatternMinDepth		(xmlPatternPtr comp)
Check the minimum depth reachable by a pattern, 0 mean the / or . are part of the set.
`comp`: | the precompiled pattern
`Returns`: | -1 in case of error otherwise the depth,
### Function: xmlPatternStreamable
    int	xmlPatternStreamable		(xmlPatternPtr comp)
Check if the pattern is streamable i.e. xmlPatternGetStreamCtxt() should work.
`comp`: | the precompiled pattern
`Returns`: | 1 if streamable, 0 if not and -1 in case of error.
### Function: xmlPatterncompile
    xmlPatternPtr	xmlPatterncompile	(const xmlChar * pattern,
    					 xmlDict * dict,
    					 int flags,
    					 const xmlChar ** namespaces)
Compile a pattern.
`pattern`: | the pattern to compile
`dict`: | an optional dictionary for interned strings
`flags`: | compilation flags, see xmlPatternFlags
`namespaces`: | the prefix definitions, array of [URI, prefix] or NULL
`Returns`: | the compiled form of the pattern or NULL in case of error
### Function: xmlStreamPop
    int	xmlStreamPop			(xmlStreamCtxtPtr stream)
push one level from the stream.
`stream`: | the stream context
`Returns`: | -1 in case of error, 0 otherwise.
### Function: xmlStreamPush
    int	xmlStreamPush			(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns)
Push new data onto the stream. NOTE: if the call xmlPatterncompile() indicated a dictionary, then strings for name and ns will be expected to come from the dictionary. Both @name and @ns being NULL means the / i.e. the root of the document. This can also act as a reset. Otherwise the function will act as if it has been given an element-node.
`stream`: | the stream context
`name`: | the current name
`ns`: | the namespace name
`Returns`: | -1 in case of error, 1 if the current state in the stream is a match and 0 otherwise.
### Function: xmlStreamPushAttr
    int	xmlStreamPushAttr		(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns)
Push new attribute data onto the stream. NOTE: if the call xmlPatterncompile() indicated a dictionary, then strings for name and ns will be expected to come from the dictionary. Both @name and @ns being NULL means the / i.e. the root of the document. This can also act as a reset. Otherwise the function will act as if it has been given an attribute-node.
`stream`: | the stream context
`name`: | the current name
`ns`: | the namespace name
`Returns`: | -1 in case of error, 1 if the current state in the stream is a match and 0 otherwise.
### Function: xmlStreamPushNode
    int	xmlStreamPushNode		(xmlStreamCtxtPtr stream,
    					 const xmlChar * name,
    					 const xmlChar * ns,
    					 int nodeType)
Push new data onto the stream. NOTE: if the call xmlPatterncompile() indicated a dictionary, then strings for name and ns will be expected to come from the dictionary. Both @name and @ns being NULL means the / i.e. the root of the document. This can also act as a reset. Different from xmlStreamPush() this function can be fed with nodes of type: element-, attribute-, text-, cdata-section-, comment- and processing-instruction-node.
`stream`: | the stream context
`name`: | the current name
`ns`: | the namespace name
`nodeType`: | the type of the node being pushed
`Returns`: | -1 in case of error, 1 if the current state in the stream is a match and 0 otherwise.
### Function: xmlStreamWantsAnyNode
    int	xmlStreamWantsAnyNode		(xmlStreamCtxtPtr streamCtxt)
Query if the streaming pattern additionally needs to be fed with text-, cdata-section-, comment- and processing-instruction-nodes. If the result is 0 then only element-nodes and attribute-nodes need to be pushed.
`streamCtxt`: | the stream context
`Returns`: | 1 in case of need of nodes of the above described types, 0 otherwise. -1 on API errors.
Daniel Veillard