|  |  |  | Rasqal RDF Query Library Manual |  | 
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typedef rasqal_graph_pattern; int rasqal_graph_pattern_add_constraint (rasqal_graph_pattern *gp, rasqal_expression *expr); void rasqal_graph_pattern_add_sub_graph_pattern (rasqal_graph_pattern *graph_pattern, rasqal_graph_pattern *sub_graph_pattern); rasqal_expression* rasqal_graph_pattern_get_constraint (rasqal_graph_pattern *gp, int idx); raptor_sequence* rasqal_graph_pattern_get_constraint_sequence (rasqal_graph_pattern *gp); int rasqal_graph_pattern_get_flags (rasqal_graph_pattern *graph_pattern); int rasqal_graph_pattern_get_index (rasqal_graph_pattern *gp); rasqal_graph_pattern_operator rasqal_graph_pattern_get_operator (rasqal_graph_pattern *graph_pattern); rasqal_graph_pattern* rasqal_graph_pattern_get_sub_graph_pattern (rasqal_graph_pattern *graph_pattern, int idx); raptor_sequence* rasqal_graph_pattern_get_sub_graph_pattern_sequence (rasqal_graph_pattern *graph_pattern); rasqal_triple* rasqal_graph_pattern_get_triple (rasqal_graph_pattern *graph_pattern, int idx); enum rasqal_graph_pattern_operator; const char* rasqal_graph_pattern_operator_as_string (rasqal_graph_pattern_operator op); void rasqal_graph_pattern_print (rasqal_graph_pattern *gp, FILE *fh); int (*rasqal_graph_pattern_visit_fn) (rasqal_query *query, rasqal_graph_pattern *gp, void *user_data); int rasqal_graph_pattern_visit (rasqal_query *query, rasqal_graph_pattern *gp, rasqal_graph_pattern_visit_fn fn, void *user_data);
Graph patterns form a a tree structure that build a rasqal_query
top-level graph pattern (see rasqal_query_get_query_graph_pattern())
which may have sub-graph patterns.  Graph patterns at the leaf of the
tree operate over triple patterns (rasqal_triple) matching the
RDF triples in the data sources for RASQAL_GRAPH_PATTERN_OPERATOR_BASIC
or RASQAL_GRAPH_PATTERN_OPERATOR_OPTIONAL.  Other graph patterns
operators operate over sub graph patterns and group them, union them
or apply a GRAPH matching keyword (RASQAL_GRAPH_PATTERN_OPERATOR_GRAPH).
int         rasqal_graph_pattern_add_constraint
                                            (rasqal_graph_pattern *gp,
                                             rasqal_expression *expr);
Add a constraint expression to the graph_pattern.
| gp: | rasqal_graph_pattern query object | 
| expr: | rasqal_expression expr | 
| Returns : | non-0 on failure | 
void        rasqal_graph_pattern_add_sub_graph_pattern
                                            (rasqal_graph_pattern *graph_pattern,
                                             rasqal_graph_pattern *sub_graph_pattern);
Add a sub graph pattern to a graph pattern .
| graph_pattern: | graph pattern to add to | 
| sub_graph_pattern: | graph pattern to add inside | 
rasqal_expression* rasqal_graph_pattern_get_constraint (rasqal_graph_pattern *gp, int idx);
Get a constraint in the sequence of constraint expressions in the query.
| gp: | rasqal_graph_pattern query object | 
| idx: | index into the sequence (0 or larger) | 
| Returns : | a rasqal_expression pointer or NULL if out of the sequence range | 
raptor_sequence* rasqal_graph_pattern_get_constraint_sequence (rasqal_graph_pattern *gp);
Get the sequence of constraints expressions in the query.
| gp: | rasqal_graph_pattern object | 
| Returns : | a raptor_sequence of rasqal_expression pointers. | 
int rasqal_graph_pattern_get_flags (rasqal_graph_pattern *graph_pattern);
Get the graph pattern flags .
deprecated: Always returns 0
| graph_pattern: | rasqal_graph_pattern graph pattern object | 
| Returns : | 0 | 
int rasqal_graph_pattern_get_index (rasqal_graph_pattern *gp);
Get the graph pattern absolute index in the array of graph patterns.
The graph pattern index is assigned when rasqal_query_prepare() is
run on a query containing a graph pattern.
| gp: | rasqal_graph_pattern graph pattern | 
| Returns : | index or <0 if no index has been assigned yet | 
rasqal_graph_pattern_operator rasqal_graph_pattern_get_operator (rasqal_graph_pattern *graph_pattern);
Get the graph pattern operator .
The operator for the given graph pattern. See also
rasqal_graph_pattern_operator_as_string().
| graph_pattern: | rasqal_graph_pattern graph pattern object | 
| Returns : | graph pattern operator | 
rasqal_graph_pattern* rasqal_graph_pattern_get_sub_graph_pattern (rasqal_graph_pattern *graph_pattern, int idx);
Get a sub-graph pattern inside a graph pattern.
| graph_pattern: | rasqal_graph_pattern graph pattern object | 
| idx: | index into the sequence of sub graph_patterns in the graph pattern | 
| Returns : | rasqal_graph_pattern or NULL if out of range | 
raptor_sequence* rasqal_graph_pattern_get_sub_graph_pattern_sequence (rasqal_graph_pattern *graph_pattern);
Get the sequence of graph patterns inside a graph pattern .
| graph_pattern: | rasqal_graph_pattern graph pattern object | 
| Returns : | a raptor_sequence of rasqal_graph_pattern pointers. | 
rasqal_triple* rasqal_graph_pattern_get_triple (rasqal_graph_pattern *graph_pattern, int idx);
Get a triple inside a graph pattern.
| graph_pattern: | rasqal_graph_pattern graph pattern object | 
| idx: | index into the sequence of triples in the graph pattern | 
| Returns : | rasqal_triple or NULL if out of range | 
typedef enum {
  RASQAL_GRAPH_PATTERN_OPERATOR_UNKNOWN   = 0,
  RASQAL_GRAPH_PATTERN_OPERATOR_BASIC     = 1,
  RASQAL_GRAPH_PATTERN_OPERATOR_OPTIONAL  = 2,
  RASQAL_GRAPH_PATTERN_OPERATOR_UNION     = 3,
  RASQAL_GRAPH_PATTERN_OPERATOR_GROUP     = 4,
  RASQAL_GRAPH_PATTERN_OPERATOR_GRAPH     = 5,
  RASQAL_GRAPH_PATTERN_OPERATOR_LAST=RASQAL_GRAPH_PATTERN_OPERATOR_GRAPH
} rasqal_graph_pattern_operator;
Graph pattern operators
const char* rasqal_graph_pattern_operator_as_string
                                            (rasqal_graph_pattern_operator op);
Get a string for the query verb.
| op: | the rasqal_graph_pattern_operator verb of the query | 
| Returns : | pointer to a shared string label for the query verb | 
void rasqal_graph_pattern_print (rasqal_graph_pattern *gp, FILE *fh);
Print a rasqal_graph_pattern in a debug format.
The print debug format may change in any release.
| gp: | the rasqal_graph_pattern object | 
| fh: | the FILE* handle to print to | 
int         (*rasqal_graph_pattern_visit_fn)
                                            (rasqal_query *query,
                                             rasqal_graph_pattern *gp,
                                             void *user_data);
User function to visit an graph_pattern and operate on it with
rasqal_graph_pattern_visit() or rasqal_query_graph_pattern_visit()
| query: | rasqal_query containing the graph pattern | 
| gp: | current graph_pattern | 
| user_data: | user data passed in | 
| Returns : | 0 to truncate the visit | 
int rasqal_graph_pattern_visit (rasqal_query *query, rasqal_graph_pattern *gp, rasqal_graph_pattern_visit_fn fn, void *user_data);
Visit a user function over a rasqal_graph_pattern
If the user function fn returns 0, the visit is truncated.
| query: | rasqal_query to operate on | 
| gp: | rasqal_graph_pattern graph pattern | 
| fn: | pointer to function to apply that takes user data and graph pattern parameters | 
| user_data: | user data for applied function | 
| Returns : | 0 if the visit was truncated. |