[css3-text] @text-transform order

How would we define the order to apply multiple @text-transform rules?

@text-transform a { "abc" to "cde"; }
@text-transform b { "abc" to "fgh"; }
<span style="text-transform: a b;">a</style>

Would it be "h" or "f"? I guess UA applies rules from left to right and therefore "h"?

Is it technically feasible to use the same rule for built-in values?

<span style="text-transform: a b uppercase;">a</style>
=> becomes "H"
<span style="text-transform: uppercase a b;">a</style>
=> becomes "A"

I also think prohibiting combinations could be an option for Level 3.

Thoughts?


Regards,
Koji