[SoM] Unicode mapping should be more flexible

[stephen-hawley]

SoM has built-in unicode mapping in UnicodeMapper.cs.

This needs some refactoring.
First, the static definition should be moved to an external file
Second, the mapping is current char -> String. The .NET char holds one UTF16 code point, ideally the mapping should allow UTF32 code points rather than UTF16 since swift allows > 16 bit code points. See the definition of a swift identifier here.
Finally, there should be a command line option to allow user-selectable mappings from an input file.
Suggest -unicode-mapping:file which should be allowed multiple times and each subsequent one can override previous definitions.

File format? Why not XML.

<?xml version="1.0" encoding="utf-8"?>
    <unicodemapping version="1.0">
        <map from="" to="" />
    </unicodemapping>

[chamons]

So I did some looking, and I think we should punt on this for awhile.

Here's what I found:

• We call this code in one place
• However, that is static and called by many (20+) places
• Thus, we have two and 1/2 options, either:
  • Hold onto static configuration data which is setup sometime after startup (yuck)
  • Update every called to have to pass the xml file through (double yuck)
  • Make it non-static and make all callers have an instance to call on, store data there
• There was some discussion if we could just bypass this by harvesting data somewhere to get a "full list of emoji with names".
• Turns out this isn't too bad: I wrote up a prototype].
• It is not complete, to begin with we don't sanitize the names into valid C# method names (remove spaces, &, etc).

So the real question is do we:

• Punt on this for now
• Generate a full list and make it not user editable
• Refactor the code to somehow get the xml config passed through.

Thoughts?

https://github.com/chamons/emojidump

[chamons]

Ok, correction we already have static data in the hard coded list, so adding the "load this xml and addrange it in", isn't too far from what we have already.

[chamons]

Splitting the rest of this issue into https://github.com/xamarin/maccore/issues/833