Expression functions

Functions
RDB_bool	RDB_expr_is_const (const RDB_expression *exp)
RDB_expression *	RDB_expr_resolve_varnames (const RDB_expression *exp, RDB_getobjfn *getfnp, void *getdata, RDB_exec_context *ecp, RDB_transaction *txp)
RDB_type *	RDB_expr_type (RDB_expression *exp, RDB_gettypefn *getfnp, void *arg, RDB_exec_context *ecp, RDB_transaction *txp)
RDB_expression *	RDB_bool_to_expr (RDB_bool v, RDB_exec_context *ecp)
RDB_expression *	RDB_int_to_expr (RDB_int v, RDB_exec_context *ecp)
RDB_expression *	RDB_float_to_expr (RDB_float v, RDB_exec_context *ecp)
RDB_expression *	RDB_string_to_expr (const char *v, RDB_exec_context *ecp)
RDB_expression *	RDB_obj_to_expr (const RDB_object *objp, RDB_exec_context *ecp)
RDB_expression *	RDB_table_ref (RDB_object *tbp, RDB_exec_context *ecp)
RDB_expression *	RDB_var_ref (const char *attrname, RDB_exec_context *ecp)
RDB_expression *	RDB_ro_op (const char *opname, RDB_exec_context *ecp)
void	RDB_add_arg (RDB_expression *exp, RDB_expression *argp)
RDB_expression *	RDB_eq (RDB_expression *arg1, RDB_expression *arg2, RDB_exec_context *ecp)
RDB_expression *	RDB_tuple_attr (RDB_expression *arg, const char *attrname, RDB_exec_context *ecp)
RDB_expression *	RDB_expr_comp (RDB_expression *arg, const char *compname, RDB_exec_context *ecp)
int	RDB_drop_expr (RDB_expression *exp, RDB_exec_context *ecp)
int	RDB_evaluate (RDB_expression *exp, RDB_getobjfn *getfnp, void *getdata, RDB_exec_context *ecp, RDB_transaction *txp, RDB_object *valp)
int	RDB_evaluate_bool (RDB_expression *exp, RDB_getobjfn *getfnp, void *getdata, RDB_exec_context *ecp, RDB_transaction *txp, RDB_bool *resp)
RDB_expression *	RDB_dup_expr (const RDB_expression *exp, RDB_exec_context *ecp)
RDB_object *	RDB_expr_obj (RDB_expression *exp)

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Function Documentation

void RDB_add_arg	(	RDB_expression *	exp,
		RDB_expression *	argp
	)

RDB_add_arg adds the child expression *argp to the expression *exp. exp must represent a read-only operator invocation. RDB_ro_op() should be used to create such an expression.

To obtain a valid expression representing a read-only operator invocation, RDB_add_arg must be called once for each argument of the operator.

RDB_expression* RDB_bool_to_expr	(	RDB_bool	v,
		RDB_exec_context *	ecp
	)

RDB_bool_to_expr creates a constant expression of type BOOLEAN.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

int RDB_drop_expr	(	RDB_expression *	exp,
		RDB_exec_context *	ecp
	)

RDB_drop_expr destroys the expression specified to by exp (including all subexpressions) and frees all resources associated with it.

Returns:

RDB_OK on success, RDB_ERROR on failure.

Errors:

The call may fail for a system error.

RDB_expression* RDB_dup_expr	(	const RDB_expression *	exp,
		RDB_exec_context *	ecp
	)

Create a copy of an expression.

RDB_expression* RDB_eq	(	RDB_expression *	arg1,
		RDB_expression *	arg2,
		RDB_exec_context *	ecp
	)

RDB_eq creates an expression that represents an "is equal" operator. If one of the arguments is NULL, NULL is returned.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_expr_comp	(	RDB_expression *	arg,
		const char *	compname,
		RDB_exec_context *	ecp
	)

RDB_expr_comp creates an expression which evaluates to a possible representation component.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_bool RDB_expr_is_const

(

const RDB_expression *

exp

)

RDB_expr_is_const returns if the expression is a constant expression.

Returns:

RDB_TRUE if the expression is a constant expression, RDB_FALSE otherwise.

RDB_object* RDB_expr_obj

(

RDB_expression *

exp

)

RDB_expr_obj returns a pointer to RDB_object embedded in an expression.

Returns:

A pointer to the embedded RDB_object or NULL if the expression does not represent a RDB_object.

RDB_expression* RDB_float_to_expr	(	RDB_float	v,
		RDB_exec_context *	ecp
	)

RDB_float_to_expr creates a constant expression of type FLOAT.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_int_to_expr	(	RDB_int	v,
		RDB_exec_context *	ecp
	)

RDB_int_to_expr creates a constant expression of type INTEGER.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_obj_to_expr	(	const RDB_object *	objp,
		RDB_exec_context *	ecp
	)

RDB_obj_to_expr creates a constant expression from a RDB_object.

Passing an objp of NULL is equivalent to passing a pointer to a RDB_object which has been newly initialized using RDB_init_obj().

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_ro_op	(	const char *	opname,
		RDB_exec_context *	ecp
	)

RDB_ro_op creates an expression which represents the invocation of a readonly operator.

Use RDB_add_arg() to add arguments.

Returns:

On success, a pointer to the newly created expression is returned. If the expression could not be created due to insufficient memory, NULL is returned and an error is left in *ecp.

RDB_expression* RDB_string_to_expr	(	const char *	v,
		RDB_exec_context *	ecp
	)

RDB_string_to_expr creates a constant expression of type STRING.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_table_ref	(	RDB_object *	tbp,
		RDB_exec_context *	ecp
	)

RDB_table_ref creates an expression which refers to a table.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_tuple_attr	(	RDB_expression *	arg,
		const char *	attrname,
		RDB_exec_context *	ecp
	)

RDB_tuple_attr creates an expression that represents a tuple attribute extraction.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

RDB_expression* RDB_var_ref	(	const char *	attrname,
		RDB_exec_context *	ecp
	)

RDB_var_ref creates an expression that refers to a variable.

Returns:

A pointer to the newly created expression, of NULL if the creation failed.

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