On 16 August 2015 at 18:35, Blake McBride <[email protected]> wrote:
> My own opinion: > > 1. Very strongly - *⍴,'A̲'* has got to equal 1 no matter what !! > You may think so, but if you want to be consistent on that, you would have to implement a completely new character set and abandon Unicode. I'll give you an example. What would you want ⍴,'ä' to be? Right now, that could return either 1 or 2 depending on whether the ä was using the precomposed character (U+00E4) or the combining mark (U+0061, U+0308). Visually, these are identical, and generally you'd expect them to compare equal. In Unicode, the comparison of equivalent (but with different characters) strings are done by performing a normalisation step prior to comparison. There are 4 different types of normalisation <http://unicode.org/reports/tr15/>, with different behaviour. Now, the ä character has a precomposed form in Unicode, and if you couple that with the NFC normalisation form, you'd get the above expression to return 1. *However,* the reason for ä working is only because there is a precomposed form available. The combining underline does not have that. So if you want to suggest that the expression applied on an underlined character should return 1, you *also* have to provide a suggestion as to what ⎕UCS X should return. Remember that ⎕UCS has to satisfy (X=⎕UCS ⎕UCS X). Regards, Elias
