]> Expressions 3 RASQAL Library Expressions Query language expressions. typedef rasqal_expression; enum rasqal_op; enum rasqal_compare_flags; enum rasqal_pattern_flags; rasqal_expression* rasqal_new_0op_expression (rasqal_op op); rasqal_expression* rasqal_new_1op_expression (rasqal_op op, rasqal_expression *arg); rasqal_expression* rasqal_new_2op_expression (rasqal_op op, rasqal_expression *arg1, rasqal_expression *arg2); rasqal_expression* rasqal_new_3op_expression (rasqal_op op, rasqal_expression *arg1, rasqal_expression *arg2, rasqal_expression *arg3); rasqal_expression* rasqal_new_cast_expression (raptor_uri *name, rasqal_expression *value); rasqal_expression* rasqal_new_function_expression (raptor_uri *name, raptor_sequence *args); rasqal_expression* rasqal_new_literal_expression (rasqal_literal *literal); rasqal_expression* rasqal_new_string_op_expression (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_query *query, rasqal_expression *e, int flags); void 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. rasqal_expressiontypedef struct rasqal_expression_s rasqal_expression; expression (arg1), unary op (arg1), binary op (arg1,arg2), literal or variable rasqal_optypedef 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, /* internal */ RASQAL_EXPR_LAST= RASQAL_EXPR_SAMETERM } 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. RASQAL_EXPR_UNKNOWN Internal RASQAL_EXPR_AND Expression for AND(A, B) RASQAL_EXPR_OR Expression for OR(A, B) RASQAL_EXPR_EQ Expression for A equals B RASQAL_EXPR_NEQ Expression for A not equals B. RASQAL_EXPR_LT Expression for A less than B. RASQAL_EXPR_GT Expression for A greather than B. RASQAL_EXPR_LE Expression for A less than or equal to B. RASQAL_EXPR_GE Expression for A greater than or equal to B. RASQAL_EXPR_UMINUS Expression for -A. RASQAL_EXPR_PLUS Expression for +A. RASQAL_EXPR_MINUS Expression for A-B. RASQAL_EXPR_STAR Expression for A*B. RASQAL_EXPR_SLASH Expression for A/B. RASQAL_EXPR_REM Expression for A/B remainder. RASQAL_EXPR_STR_EQ Expression for A string equals B. RASQAL_EXPR_STR_NEQ Expression for A string not-equals B. RASQAL_EXPR_STR_MATCH Expression for string A matches literal regex B with flags. RASQAL_EXPR_STR_NMATCH Expression for string A not-matches literal regex B with flags. RASQAL_EXPR_TILDE Expression for binary not A. RASQAL_EXPR_BANG Expression for logical not A. RASQAL_EXPR_LITERAL Expression for a rasqal_literal. RASQAL_EXPR_FUNCTION Expression for a function A with arguments (B...). RASQAL_EXPR_BOUND Expression for SPARQL ISBOUND(A). RASQAL_EXPR_STR Expression for SPARQL STR(A). RASQAL_EXPR_LANG Expression for SPARQL LANG(A). RASQAL_EXPR_DATATYPE Expression for SPARQL DATATYPE(A). RASQAL_EXPR_ISURI Expression for SPARQL ISURI(A). RASQAL_EXPR_ISBLANK Expression for SPARQL ISBLANK(A). RASQAL_EXPR_ISLITERAL Expression for SPARQL ISLITERAL(A). RASQAL_EXPR_CAST Expression for cast literal A to type B. RASQAL_EXPR_ORDER_COND_ASC Expression for SPARQL order condition ascending. RASQAL_EXPR_ORDER_COND_DESC Expression for SPARQL order condition descending. RASQAL_EXPR_LANGMATCHES Expression for SPARQL LANGMATCHES(A, B). RASQAL_EXPR_REGEX Expression for string A matches expression regex B with flags. RASQAL_EXPR_GROUP_COND_ASC Expression for LAQRS group condition ascending. RASQAL_EXPR_GROUP_COND_DESC Expression for LAQRS group condition descending. RASQAL_EXPR_COUNT Expression for LAQRS select COUNT() RASQAL_EXPR_VARSTAR Expression for LAQRS select Variable * RASQAL_EXPR_SAMETERM Expression for SPARQL sameTerm RASQAL_EXPR_LAST Internal rasqal_compare_flagstypedef enum { RASQAL_COMPARE_NOCASE = 1, RASQAL_COMPARE_XQUERY = 2, RASQAL_COMPARE_RDF = 4, RASQAL_COMPARE_URI = 8 } rasqal_compare_flags; Flags for rasqal_expression_evaluate() or rasqal_literal_compare(). RASQAL_COMPARE_NOCASE String comparisons are case independent. RASQAL_COMPARE_XQUERY XQuery comparsion rules apply. RASQAL_COMPARE_RDF RDF Term comparsion rules apply. RASQAL_COMPARE_URI Allow comparison of URIs rasqal_pattern_flagstypedef enum { RASQAL_PATTERN_FLAGS_OPTIONAL=1, RASQAL_PATTERN_FLAGS_LAST=RASQAL_PATTERN_FLAGS_OPTIONAL } rasqal_pattern_flags; Flags for rasqal_graph_pattern. RASQAL_PATTERN_FLAGS_OPTIONAL True when the graph pattern is an optional match. RASQAL_PATTERN_FLAGS_LAST Internal rasqal_new_0op_expressionrasqal_expression* rasqal_new_0op_expression (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. op : Expression operator Returns : a new rasqal_expression object or NULL on failure rasqal_new_1op_expressionrasqal_expression* rasqal_new_1op_expression (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_GROUP_COND_ASC RASQAL_EXPR_GROUP_COND_DESC RASQAL_EXPR_COUNT RASQAL_EXPR_BANG and RASQAL_EXPR_UMINUS are used by RDQL and SPARQL. RASQAL_EXPR_TILDE by RDQL only. The rest by SPARQL only. op : Expression operator arg : Operand 1 Returns : a new rasqal_expression object or NULL on failure rasqal_new_2op_expressionrasqal_expression* rasqal_new_2op_expression (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. op : Expression operator arg1 : Operand 1 arg2 : Operand 2 Returns : a new rasqal_expression object or NULL on failure rasqal_new_3op_expressionrasqal_expression* rasqal_new_3op_expression (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 op : Expression operator arg1 : Operand 1 arg2 : Operand 2 arg3 : Operand 3 (may be NULL) Returns : a new rasqal_expression object or NULL on failure rasqal_new_cast_expressionrasqal_expression* rasqal_new_cast_expression (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. name : cast datatype URI value : expression value to cast to datatype type Returns : a new rasqal_expression object or NULL on failure rasqal_new_function_expressionrasqal_expression* rasqal_new_function_expression (raptor_uri *name, raptor_sequence *args); Constructor - create a new expression for a function with expression arguments. Takes ownership of the function uri and arguments. name : function name args : sequence of rasqal_expression function arguments Returns : a new rasqal_expression object or NULL on failure rasqal_new_literal_expressionrasqal_expression* rasqal_new_literal_expression (rasqal_literal *literal); Constructor - create a new expression for a rasqal_literal Takes ownership of the operand literal. literal : Literal operand 1 Returns : a new rasqal_expression object or NULL on failure rasqal_new_string_op_expressionrasqal_expression* rasqal_new_string_op_expression (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) op : Expression operator arg1 : Operand 1 literal : Literal operand 2 Returns : a new rasqal_expression object or NULL on failure rasqal_new_expression_from_expressionrasqal_expression* rasqal_new_expression_from_expression (rasqal_expression *e); Copy Constructor - create a new rasqal_expression object from an existing rasqal_expression object. e : rasqal_expression object to copy Returns : a new rasqal_expression object or NULL on failure rasqal_free_expressionvoid rasqal_free_expression (rasqal_expression *e); Destructor - destroy a rasqal_expression object. e : rasqal_expression object rasqal_expression_evaluaterasqal_literal* rasqal_expression_evaluate (rasqal_query *query, rasqal_expression *e, int flags); Evaluate a rasqal_expression tree to give a rasqal_literal result or error. query : rasqal_query this expression belongs to e : The expression to evaluate. flags : Flags for rasqal_literal_compare() and RASQAL_COMPARE_NOCASE for string matches. Returns : a rasqal_literal value or NULL on failure. rasqal_expression_printvoid 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. e : rasqal_expression object. fh : The FILE* handle to print to. rasqal_expression_print_opvoid 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. e : the rasqal_expression object fh : the FILE* handle to print to rasqal_expression_visit_fnint (*rasqal_expression_visit_fn) (void *user_data, rasqal_expression *e); User function to visit an expression and operate on it with rasqal_expression_visit() user_data : user data passed in with rasqal_expression_visit() e : current expression Returns : 0 to truncate the visit rasqal_expression_visitint 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 0, the visit is truncated. e : rasqal_expression to visit fn : visit function user_data : user data to pass to visit function Returns : 0 if the visit was truncated.