[Pre-RFC] Opt-in JSON comments and trailing commas

Hello!

I would like to discuss a draft RFC that adds two independent and
opt-in flags to ext/json for PHP 8.7:

• JSON_ALLOW_COMMENTS
• JSON_ALLOW_TRAILING_COMMAS

Both flags would be accepted by json_decode() and json_validate().
Strict JSON would remain the default. Comments are limited to // and
non-nesting /* ... */ at JSON whitespace boundaries. Trailing commas
permit one comma after the last element or member of a nonempty array
or object.

The implementation processes comments in the existing re2c scanner. It
handles trailing commas in the existing Bison grammar. It does not
preprocess or copy the input, so it preserves strings and original
source locations. The RFC uses two primary votes so that either
extension can be accepted independently.

Draft implementation is located here: https://github.com/php/php-src/pull/23336

Recently I also published a similar PHP library: https://github.com/otar/jsonc

I would particularly appreciate feedback on the API names and the
inclusion of json_validate(). Feedback on the specified UTF-8,
control-character, and error-location behavior would also be useful.

Otar

Does this essentially mean JSON5 support? If so, just call it that. (I am undecided on the best way to support that.)

--Larry Garfield