Re: [PATCH 01/18] qapi: Smarter camel_to_upper() to reduce need for 'prefix'

[Kevin Wolf]

Am 30.07.2024 um 10:10 hat Markus Armbruster geschrieben:
> camel_to_upper() converts its argument from camel case to upper case
> with '_' between words.  Used for generated enumeration constant
> prefixes.
> 
> When some of the words are spelled all caps, where exactly to insert
> '_' is guesswork.  camel_to_upper()'s guesses are bad enough in places
> to make people override them with a 'prefix' in the schema.
> 
> Rewrite it to guess better:
> 
> 1. Insert '_' after a non-upper case character followed by an upper
>    case character:
> 
>        OneTwo -> ONE_TWO
>        One2Three -> ONE2_THREE
> 
> 2. Insert '_' before the last upper case character followed by a
>    non-upper case character:
> 
>        ACRONYMWord -> ACRONYM_Word
> 
>    Except at the beginning (as in OneTwo above), or when there is
>    already one:
> 
>        AbCd -> AB_CD

Maybe it's just me, but the exception "at the beginning" (in the sense
of "after the first character") seems to be exactly where I thought
"that looks strange" while going through your list below. In particular,
I'd expect X_DBG_* instead of XDBG_*. I also thought that the Q_*
spelling made more sense, though this might be less clear. But in case
of doubt, less exceptions seems like a good choice.

> +    # Copy remainder of ``value`` to ``ret`` with '_' inserted
> +    for ch in value[1:]:
> +        if ch.isupper() == upc:
> +            pass
> +        elif upc:
> +            # ``ret`` ends in upper case, next char isn't: insert '_'
> +            # before the last upper case char unless there is one
> +            # already, or it's at the beginning
> +            if len(ret) > 2 and ret[-2] != '_':
> +                ret = ret[:-1] + '_' + ret[-1]

I think in the code this means I would have expected len(ret) >= 2.

Kevin