scalars and 0-dim arrays in expressions #621
Description
0-dim arrays are treated like scalars when evaluating an expression, but an expression cannot be evaluated without an array operand. That means, that if all the operands are scalars or 0-dim arrays, an error will be raised. Keep in mind that the reductions along the whole axis return a 0-dim array (as the Array API standard says). This should be fixed in order to compute simple operations.