Can we get compile time routines?

[divinity76]

Description

I have a large multi-megabyte JSON that is currently parsed several times per second, I also have OPCache enabled, would save time if the parsing could be done at compile-time rather than runtime, would be nice if i could do something like

$data = compile_time_routine(function() {
    return json_decode(file_get_contents("large.json"), true);
});

instead of

$data = json_decode(file_get_contents("large.json"), true);

with it being equivalent at runtime to

$data = array(...whatever json_decode returned...);

another example would be

echo "opcache compiled at " . compile_time_routine(function(){return date(DateTime::RFC3339);});

being equivalent at runtime to

echo "opcache compiled at " . "2023-03-16T09:43:00+01:00";

(i did not give the function name/argument/details much thought fwiw)

[damianwadley]

If you don't mind putting more thought into how this sort of thing might work, that would make it easier to raise the subject on the internals mailing list for discussion. Which is the first step of the RFC process.
https://wiki.php.net/rfc/howto

In the meantime, it's fairly common to have build tools that generate PHP files. Such as

$data = json_decode(file_get_contents("large.json"), true);
file_put_contents("large.php", "<?php return " . var_export($data, true) . ";\n");