For 5.19.2 ARABIC:
Remove from Portable Constraints:
X must contain at least one Roman numeral, and only contain Roman numerals.
Add Constraint:
X must only contain Roman numerals, or an empty string.
In Semantics:
Remove the sentence
The symbols V, L and D may not be followed by a symbol of greater or equal value.
Change
The following identity holds ...
to
The following identity shall hold ...
Add:
If X is an empty string, 0 is returned.
[rationale for empty string: that is what ROMAN produces for 0]
For 5.19.17 ROMAN:
Change Portable Constraint
from
N>=1
to
N>=0
In Semantics:
Add:
If N is 0, an empty string is returned.
[rationale: Excel, Gnumeric, OOo and KSpread return an empty string for 0]
Change
The following identity holds ...
to
The following identity shall hold ...