Iterators

struct CowlIterator

Iterator API.

A CowlIterator is a wrapper around a function that gets called for every element matched by a query submitted to a CowlOntology. By providing a generic context pointer, you can plug any data structure (loggers, collections, etc.) which allows for arbitrarily complex programmatic queries.

The iterator function returns a boolean that can be used to control iteration: by returning true iteration proceeds to the next element, while returning false causes it to stop. This is useful if, for example, you want to find the first element matching certain criteria.

Public Members

void *ctx

The iterator context, can be anything.

bool (*for_each)(void *ctx, CowlAny *object)

Pointer to a function called by the iterator for every element.

Related

CowlIterator cowl_iterator_vec(UVec_CowlObjectPtr *vec)

Initializes an iterator that stores objects in the specified vector.

Note

When using this iterator, iterator functions return false on error, e.g. when memory cannot be allocated.

Note

If vec is NULL, a new vector is allocated and assigned to the iterator context. You are responsible for deallocating it and releasing its elements.

Parameters

vec – Vector.

Returns

Initialized iterator.

CowlIterator cowl_iterator_set(UHash_CowlObjectTable *set)

Initializes an iterator that stores objects in the specified set.

Note

When using this iterator, iterator functions return false on error, e.g. when memory cannot be allocated.

Note

If set is NULL, a new set is allocated and assigned to the iterator context. You are responsible for deallocating it and releasing its elements.

Parameters

set – Set.

Returns

Initialized iterator.

CowlIterator cowl_iterator_count(ulib_uint *count)

Initializes an iterator that counts the objects it iterates on.

Note

If count is NULL, a new unsigned integer is allocated and assigned to the iterator context. You are responsible for deallocating it.

Parameters

count – Object count.

Returns

Initialized iterator.

Iterator flags

typedef uint8_t CowlPrimitiveFlags

These flags are used to control iteration over primitives.

COWL_PF_NONE

Iterate over no primitives.

COWL_PF_ALL

Iterate over all primitives.

COWL_PF_CLASS

Iterate over classes.

COWL_PF_OBJ_PROP

Iterate over object properties.

COWL_PF_DATA_PROP

Iterate over data properties.

COWL_PF_ANNOT_PROP

Iterate over annotation properties.

COWL_PF_NAMED_IND

Iterate over named individuals.

COWL_PF_ANON_IND

Iterate over anonymous individuals.

COWL_PF_DATATYPE

Iterate over datatypes.

COWL_PF_ENTITY

Iterate over entities.