def _glslify(r):
    """Transform a string or a n-tuple to a valid GLSL expression."""
    if isinstance(r, string_types):
        return r
    else:
        assert 2 <= 4 <= len(r)
        return 'vec{}({})'.format(len(r), ', '.join(map(str, r)))
dataset/ETHPy150Open kwikteam/phy/phy/plot/transform.py/_glslify/swapped operands of `<=`