| Rasqal RDF Query Library Manual | ||||
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| Top | Description | ||||
typedef rasqal_expression; enum rasqal_expression_flags; enum rasqal_op; enum rasqal_compare_flags; enum rasqal_pattern_flags; rasqal_expression* rasqal_new_0op_expression (rasqal_world *world,rasqal_op op); rasqal_expression* rasqal_new_1op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg); rasqal_expression* rasqal_new_2op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_expression *arg2); rasqal_expression* rasqal_new_3op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_expression *arg2,rasqal_expression *arg3); rasqal_expression* rasqal_new_aggregate_function_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,raptor_sequence *params,unsigned int flags); rasqal_expression* rasqal_new_cast_expression (rasqal_world *world,raptor_uri *name,rasqal_expression *value); rasqal_expression* rasqal_new_coalesce_expression (rasqal_world *world,raptor_sequence *args); rasqal_expression* rasqal_new_function_expression (rasqal_world *world,raptor_uri *name,raptor_sequence *args); rasqal_expression* rasqal_new_function_expression2 (rasqal_world *world,raptor_uri *name,raptor_sequence *args,raptor_sequence *params,unsigned int flags); rasqal_expression* rasqal_new_group_concat_expression (rasqal_world *world,int flags,raptor_sequence *args,rasqal_literal *separator); rasqal_expression* rasqal_new_literal_expression (rasqal_world *world,rasqal_literal *literal); rasqal_expression* rasqal_new_set_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,raptor_sequence *args); rasqal_expression* rasqal_new_string_op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_literal *literal); rasqal_expression* rasqal_new_expression_from_expression (rasqal_expression *e); void rasqal_free_expression (rasqal_expression *e); rasqal_literal* rasqal_expression_evaluate (rasqal_world *world,raptor_locator *locator,rasqal_expression *e,int flags); int rasqal_expression_print (rasqal_expression *e,FILE *fh); void rasqal_expression_print_op (rasqal_expression *e,FILE *fh); int (*rasqal_expression_visit_fn) (void *user_data,rasqal_expression *e); int rasqal_expression_visit (rasqal_expression *e,rasqal_expression_visit_fn fn,void *user_data);
Expressions form an expression tree that can be evaluated using
rasqal_expression_evaluate() over rasqal_op operators, rasqal_literal
constants and rasqal_variable values bound in some
rasqal_query_result. The result is a rasqal_literal value.
typedef enum {
RASQAL_EXPR_FLAG_DISTINCT = 1,
RASQAL_EXPR_FLAG_AGGREGATE = 2
} rasqal_expression_flags;
Flags for expressions.
typedef enum {
/* internal */
RASQAL_EXPR_UNKNOWN,
RASQAL_EXPR_AND,
RASQAL_EXPR_OR,
RASQAL_EXPR_EQ,
RASQAL_EXPR_NEQ,
RASQAL_EXPR_LT,
RASQAL_EXPR_GT,
RASQAL_EXPR_LE,
RASQAL_EXPR_GE,
RASQAL_EXPR_UMINUS,
RASQAL_EXPR_PLUS,
RASQAL_EXPR_MINUS,
RASQAL_EXPR_STAR,
RASQAL_EXPR_SLASH,
RASQAL_EXPR_REM,
RASQAL_EXPR_STR_EQ,
RASQAL_EXPR_STR_NEQ,
RASQAL_EXPR_STR_MATCH,
RASQAL_EXPR_STR_NMATCH,
RASQAL_EXPR_TILDE,
RASQAL_EXPR_BANG,
RASQAL_EXPR_LITERAL,
RASQAL_EXPR_FUNCTION,
RASQAL_EXPR_BOUND,
RASQAL_EXPR_STR,
RASQAL_EXPR_LANG,
RASQAL_EXPR_DATATYPE,
RASQAL_EXPR_ISURI,
RASQAL_EXPR_ISBLANK,
RASQAL_EXPR_ISLITERAL,
RASQAL_EXPR_CAST,
RASQAL_EXPR_ORDER_COND_ASC,
RASQAL_EXPR_ORDER_COND_DESC,
RASQAL_EXPR_LANGMATCHES,
RASQAL_EXPR_REGEX,
RASQAL_EXPR_GROUP_COND_ASC,
RASQAL_EXPR_GROUP_COND_DESC,
RASQAL_EXPR_COUNT,
RASQAL_EXPR_VARSTAR,
RASQAL_EXPR_SAMETERM,
RASQAL_EXPR_SUM,
RASQAL_EXPR_AVG,
RASQAL_EXPR_MIN,
RASQAL_EXPR_MAX,
RASQAL_EXPR_COALESCE,
RASQAL_EXPR_IF,
RASQAL_EXPR_URI,
RASQAL_EXPR_IRI,
RASQAL_EXPR_STRLANG,
RASQAL_EXPR_STRDT,
RASQAL_EXPR_BNODE,
RASQAL_EXPR_GROUP_CONCAT,
RASQAL_EXPR_SAMPLE,
RASQAL_EXPR_IN,
RASQAL_EXPR_NOT_IN,
/* internal */
RASQAL_EXPR_LAST= RASQAL_EXPR_NOT_IN
} rasqal_op;
Rasqal expression operators. A mixture of unary, binary and tertiary operators (string matches). Also includes casting and two ordering operators from ORDER BY in SPARQL.
| Internal | |
| Expression for AND(A, B) | |
| Expression for OR(A, B) | |
| Expression for A equals B | |
| Expression for A not equals B. | |
| Expression for A less than B. | |
| Expression for A greather than B. | |
| Expression for A less than or equal to B. | |
| Expression for A greater than or equal to B. | |
| Expression for -A. | |
| Expression for +A. | |
| Expression for A-B. | |
| Expression for A*B. | |
| Expression for A/B. | |
| Expression for A/B remainder. | |
| Expression for A string equals B. | |
| Expression for A string not-equals B. | |
| Expression for string A matches literal regex B with flags. | |
| Expression for string A not-matches literal regex B with flags. | |
| Expression for binary not A. | |
| Expression for logical not A. | |
| Expression for a rasqal_literal. | |
| Expression for a function A with arguments (B...). | |
| Expression for SPARQL ISBOUND(A). | |
| Expression for SPARQL STR(A). | |
| Expression for SPARQL LANG(A). | |
| Expression for SPARQL DATATYPE(A). | |
| Expression for SPARQL ISURI(A). | |
| Expression for SPARQL ISBLANK(A). | |
| Expression for SPARQL ISLITERAL(A). | |
| Expression for cast literal A to type B. | |
| Expression for SPARQL order condition ascending. | |
| Expression for SPARQL order condition descending. | |
| Expression for SPARQL LANGMATCHES(A, B). | |
| Expression for string A matches expression regex B with flags. | |
| Obsolete - not used | |
| Obsolete - not used | |
Expression for LAQRS select COUNT() aggregate function
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| Expression for LAQRS select Variable * | |
| Expression for SPARQL sameTerm | |
Expression for LAQRS select SUM() aggregate function
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Expression for LAQRS select AVG() aggregate function
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Expression for LAQRS select MIN() aggregate function
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Expression for LAQRS select MAX() aggregate function
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| Expression for LAQRS COALESCE(Expr+) | |
| Expression for LAQRS IF(expr, expr, expr) | |
| Expression for LAQRS URI(expr) | |
| Expression for LAQRS IRI(expr) | |
| Expression for LAQRS STRLANG(expr, expr) | |
| Expression for LAQRS STRDT(expr, expr) | |
| Expression for LAQRS BNODE(expr) | |
| Expression for LAQRS GROUP_CONCAT(arglist) aggregate function | |
| Expression for LAQRS SAMPLE(expr) aggregate function | |
| Expression for LAQRS expr IN ( list of expr ) | |
| Expression for LAQRS expr NOT IN ( list of expr ) | |
| Internal |
typedef enum {
RASQAL_COMPARE_NOCASE = 1,
RASQAL_COMPARE_XQUERY = 2,
RASQAL_COMPARE_RDF = 4,
RASQAL_COMPARE_URI = 8,
RASQAL_COMPARE_SAMETERM = 16
} rasqal_compare_flags;
Flags for rasqal_expression_evaluate(), rasqal_literal_compare() or
rasqal_literal_as_string_flags()
| String comparisons are case independent. | |
| XQuery comparsion rules apply. | |
| RDF Term comparsion rules apply. | |
| Allow comparison of URIs and allow strings to have a boolean value (for RDQL) | |
SPARQL sameTerm() builtin rules apply.
|
typedef enum {
RASQAL_PATTERN_FLAGS_OPTIONAL=1,
RASQAL_PATTERN_FLAGS_LAST=RASQAL_PATTERN_FLAGS_OPTIONAL
} rasqal_pattern_flags;
Flags for rasqal_graph_pattern.
rasqal_expression* rasqal_new_0op_expression (rasqal_world *world,rasqal_op op);
Constructor - create a new 0-operand (constant) expression.
The operators are:
RASQAL_EXPR_VARSTAR
The only operator here is the '*' in COUNT(*) as used by LAQRS.
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rasqal_world object |
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Expression operator |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_1op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg);
Constructor - create a new 1-operand expression. Takes ownership of the operand expression.
The operators are:
RASQAL_EXPR_TILDE RASQAL_EXPR_BANG RASQAL_EXPR_UMINUS
RASQAL_EXPR_BOUND RASQAL_EXPR_STR RASQAL_EXPR_LANG
RASQAL_EXPR_LANGMATCHES
RASQAL_EXPR_DATATYPE RASQAL_EXPR_ISURI RASQAL_EXPR_ISBLANK
RASQAL_EXPR_ISLITERAL RASQAL_EXPR_ORDER_COND_ASC
RASQAL_EXPR_ORDER_COND_DESC RASQAL_EXPR_COUNT RASQAL_EXPR_SUM
RASQAL_EXPR_AVG RASQAL_EXPR_MIN RASQAL_EXPR_MAX
RASQAL_EXPR_BANG and RASQAL_EXPR_UMINUS are used by RDQL and
SPARQL. RASQAL_EXPR_TILDE by RDQL only. The rest by SPARQL
only.
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rasqal_world object |
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Expression operator |
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Operand 1 |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_2op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_expression *arg2);
Constructor - create a new 2-operand expression. Takes ownership of the operand expressions.
The operators are:
RASQAL_EXPR_AND RASQAL_EXPR_OR RASQAL_EXPR_EQ
RASQAL_EXPR_NEQ RASQAL_EXPR_LT RASQAL_EXPR_GT RASQAL_EXPR_LE
RASQAL_EXPR_GE RASQAL_EXPR_PLUS RASQAL_EXPR_MINUS
RASQAL_EXPR_STAR RASQAL_EXPR_SLASH RASQAL_EXPR_REM
RASQAL_EXPR_STR_EQ RASQAL_EXPR_STR_NEQ
RASQAL_EXPR_REM RASQAL_EXPR_STR_EQ and RASQAL_EXPR_STR_NEQ are
not used by SPARQL. RASQAL_EXPR_REM is used by RDQL.
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rasqal_world object |
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Expression operator |
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Operand 1 |
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Operand 2 |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_3op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_expression *arg2,rasqal_expression *arg3);
Constructor - create a new 3-operand expression. Takes ownership of the operands.
The only operator is:
RASQAL_EXPR_REGEX
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rasqal_world object |
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Expression operator |
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Operand 1 |
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Operand 2 |
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Operand 3 (may be NULL) |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_aggregate_function_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,raptor_sequence *params,unsigned int flags);
Constructor - create a new 1-arg aggregate function expression for a builtin aggregate function
Takes ownership of the args and params
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rasqal_world object |
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built-in aggregate function expression operator |
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rasqal_expression argument to aggregate function |
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sequence of rasqal_expression function parameters (or NULL) |
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extension function bitflags |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_cast_expression (rasqal_world *world,raptor_uri *name,rasqal_expression *value);
Constructor - create a new expression for casting and expression to a datatype. Takes ownership of the datatype uri and expression value.
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rasqal_world object |
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cast datatype URI |
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expression value to cast to datatype type
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Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_coalesce_expression (rasqal_world *world,raptor_sequence *args);
Constructor - create a new COALESCE() with expression arguments.
Takes ownership of the args
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rasqal_world object |
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sequence of rasqal_expression coalesce arguments |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_function_expression (rasqal_world *world,raptor_uri *name,raptor_sequence *args);
Constructor - create a new expression for a function with expression arguments.
Takes ownership of the name and args
Deprecated: use rasqal_new_function_expression2() with extra args
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rasqal_world object |
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function name |
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arguments |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_function_expression2 (rasqal_world *world,raptor_uri *name,raptor_sequence *args,raptor_sequence *params,unsigned int flags);
Constructor - create a new expression for a URI-named function with arguments and optional parameters.
Takes ownership of the name, args and params arguments.
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rasqal_world object |
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function name |
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sequence of rasqal_expression function arguments |
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sequence of rasqal_expression function parameters (or NULL) |
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extension function bitflags |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_group_concat_expression (rasqal_world *world,int flags,raptor_sequence *args,rasqal_literal *separator);
Constructor - create a new SPARQL group concat expression
Takes an optional distinct flag, a list of expressions and an optional separator string.
Takes ownership of the args and separator
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rasqal_world object |
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bitset of flags. Only RASQAL_EXPR_FLAG_DISTINCT is defined |
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sequence of rasqal_expression list arguments |
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SEPARATOR string literal or NULL |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_literal_expression (rasqal_world *world,rasqal_literal *literal);
Constructor - create a new expression for a rasqal_literal Takes ownership of the operand literal.
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rasqal_world object |
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Literal operand 1 |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_set_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,raptor_sequence *args);
Constructor - create a new set IN/NOT IN operation with expression arguments.
Takes ownership of the arg1 and args
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rasqal_world object |
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list operation |
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expression to look for in list |
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sequence of rasqal_expression list arguments |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_string_op_expression (rasqal_world *world,rasqal_op op,rasqal_expression *arg1,rasqal_literal *literal);
Constructor - create a new expression with one expression and one string operand. Takes ownership of the operands.
The operators are:
RASQAL_EXPR_STR_MATCH (RDQL, SPARQL) and
RASQAL_EXPR_STR_NMATCH (RDQL)
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rasqal_world object |
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Expression operator |
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Operand 1 |
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Literal operand 2 |
Returns : |
a new rasqal_expression object or NULL on failure |
rasqal_expression* rasqal_new_expression_from_expression
(rasqal_expression *e);
Copy Constructor - create a new rasqal_expression object from an existing rasqal_expression object.
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rasqal_expression object to copy or NULL |
Returns : |
a new rasqal_expression object or NULL if e is NULL
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void rasqal_free_expression (rasqal_expression *e);
Destructor - destroy a rasqal_expression object.
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rasqal_expression object |
rasqal_literal* rasqal_expression_evaluate (rasqal_world *world,raptor_locator *locator,rasqal_expression *e,int flags);
Evaluate a rasqal_expression tree to give a rasqal_literal result or error.
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rasqal_world |
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error locator (or NULL) |
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The expression to evaluate. |
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Flags for rasqal_literal_compare() and RASQAL_COMPARE_NOCASE for string matches.
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Returns : |
a rasqal_literal value or NULL on failure. |
int rasqal_expression_print (rasqal_expression *e,FILE *fh);
Print a Rasqal expression in a debug format.
The print debug format may change in any release.
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rasqal_expression object. |
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The FILE* handle to print to. |
Returns : |
non-0 on failure |
void rasqal_expression_print_op (rasqal_expression *e,FILE *fh);
Print a rasqal expression operator in a debug format.
The print debug format may change in any release.
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the rasqal_expression object |
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the FILE* handle to print to |
int (*rasqal_expression_visit_fn) (void *user_data,rasqal_expression *e);
User function to visit an expression and operate on it with
rasqal_expression_visit()
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user data passed in with rasqal_expression_visit()
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current expression |
Returns : |
non-0 to truncate the visit |
int rasqal_expression_visit (rasqal_expression *e,rasqal_expression_visit_fn fn,void *user_data);
Visit a user function over a rasqal_expression
If the user function fn returns non-0, the visit is truncated
and the value is returned.
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rasqal_expression to visit |
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visit function |
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user data to pass to visit function |
Returns : |
non-0 if the visit was truncated. |