Change inflection on unions

[Emilgardis]

PascalCase doesn't work when we have overloaded registers named
FOO_11 and FOO1_1.

This happens in

• Freescale MKL81Z7
• Freescale MKL82Z7
• Freescale MK81F25615
• Freescale MK82F25615
  on LTC0_PK* registers.

I'm not sure if {ident}Union is the best choice anymore as FOO_BARUnion doesn't seem as good as it possibly could be.

cc @jamesmunns @wez

[wez]

Bummer. I'm not super opinionated on the naming here. Should we embrace uppercase and go for FOO_BAR_UNION?

[Emilgardis]

I switched it over to {}_UNION, @jamesmunns you talked briefly about the naming in #192
I ran this against svd2rust-regress and it's all clear, however I'm not sure if this naming is ideal

[jamesmunns]

Hey, ACKing that I've seen this, I don't have strong opinions on naming (other than it should be consistent).

I think I need some time to grok what is going on here, and see if I can think of anything clever. I probably will be able to get to this by Monday (feel free to re-ping me if I have forgotten :) )

[Emilgardis]

ping @jamesmunns

[jamesmunns]

Argh. I knew there was something I was forgetting. Thanks @Emilgardis.

I'm not crazy about naming the unions as upper case, as that is typically used for constants, and is a bit of a wierd interface for users. I'd rather have the naming "weird" for these edge cases, and less weird for normal usage, rather than making it equally weird for everyone.

I don't want to hold up something that works, because I don't have particularly strong feelings about naming either.

I guess my one bike shed thought would be to introduce something like Pascal_Snake_Case for unions, which would look like this:

<name>LTC0_PKA1_1</name> => Ltc0_Pka1_1_Union
<name>LTC0_PKA_11</name> => Ltc0_Pka_11_Union

Or replacing _ with a word, such as Sub:

<name>LTC0_PKA1_1</name> => Ltc0SubPka1Sub1SubUnion
<name>LTC0_PKA_11</name> => Ltc0SubPkaSub11SubUnion

But honestly this is even bad, as it introduces a new, weird naming convention, or inserts a lot of noise into words.

If no one really cares, lets go with UPPER_CASE for now, and have a follow up discussion before we move union support into the stable part of svd2rust

edit: add the _Union suffix to the examples

[Emilgardis]

@jamesmunns re unions, we may want to move away from them, see #218

I'll wait a bit and then r+, let's see if anyone has a better solution

[Emilgardis]

#L10, unused import ToSanitizedPascalCase

[Emilgardis]

passed locally with svd2rust-regress, merging manually