The syntax for concatenating arrays:
array-concatenation : array-concatenation # complex-expr-term | complex-expr-term
Semantics: The result is an array of the same dimensionality as its constituents, but the size of the first dimension is the sum of the first dimension of its constituents. The constituents, therefore, cannot be scalars. In 2 or higher dimensions, the sizes of all trailing dimensions (past the first) must match to form a valid concatenation. This construction is valid for both meta-expressions and instance-references.
Example: 1D-arrays of size [M], [N], [P] would be concatenated to form a 1D-array of size [M+N+P]. 2D-arrays of size [M][Q], [N][Q], [P][Q] would be concatenated to form a 2D-array of size [M+N+P][Q].
Status: implemented