Array operations

These operations are provided for working with array objects. Only the most commonly needed operations are supported. Generic operations such as AAdd and ACallMethod can be used as well to perform additional operations.

It is important to note that most of these operations only accept direct instances of std::Array, i.e. they do not support subtypes of Array. As a result of this limitation, these operations are fast, since they do not have to verify the type of argument objects and can directly access the internals of array objects without having to perform polymorphic method dispatches.

Code that wishes to remain faithful to Alore semantics and avoid explicit type checks may have to either use generic operations such as those described in section Collection operations or use two separate implementations, an efficient one for Array objects that uses operations described in this section, and a generic but less efficient one for objects of Array subtypes or other sequence types.

Creating

AValue AMakeArray(AThread *t, Assize_t len)

Create a std::Array object of the specified length. The object is initialized to contain nil values for all items.

Reading and updating

Assize_t AArrayLen(AValue v)

Return the length of an array. The argument must be a std::Array object, since this function performs no error checking. Subtypes of Array are not supported.

AValue AArrayItem(AValue v, Assize_t index)

Return the value of an item in an array. The first argument must be an std::Array object, and the index (0-based) must be non-negative and less than the length of the array. This function performs no error checking. Subtypes of Array are not supported.

void ASetArrayItem(AThread *t, AValue v, Assize_t index, AValue item)

Set the value of an item in an array. The second argument must be an std::Array object, and the index (0-based) must be non-negative and less than then length of the array. This function performs no error checking of the argument values. Subtypes of Array are not supported. Raise a direct exception if out of memory.

void AAppendArray(AThread *t, AValue v, AValue item)

Append an item to the end of an array, increasing the length of the array by one. The argument v must be std::Array object, since this function performs no error checking. Subtypes of Array are not supported either. Raise a direct exception if out of memory.

AValue ASubArray(AThread *t, AValue v, Assize_t i1, Assize_t i2)

Return the subarray i1:i2 of an array. The rules for indices are similar to when indexing subarrays in Alore code, and negative indices are supported. As an exception, the constant A_SLICE_END as the end index specifies a subarray extending to the end of the array. Subtypes of Array are not supported. Raise a direct exception on all error conditions.

Checking

ABool AIsArray(AValue v)

Return a boolean indicating whether the type of v is std::Array. This operations returns false for objects belonging to a subtype of Array. See also AIsArraySubType described below.

void AExpectArray(AThread *t, AValue v)

Check if the type of v is std::Array and raise a direct std::TypeError exception if it is not. The exception is raised also for objects belonging to a subtype Array.

ABool AIsArraySubType(AValue v)

Return a boolean indicating whether the type of v is std::Array or a subtype of Array.