Only determine needed emulators based on PHP version once, and
add an adaptor that allows treating forward and reverse emulation
the same.
Previously the isEmulationNeeded() check was too conservative,
as it also considered emulators that are not relevant for the
version. Though possibly that check should just be dropped
altogether.
a) Don't check for !== false, preg_match() return 0 if there is
no match. This effectively means that the check was always true.
b) Check for hex characters only if there's an 0x prefix. 1_1 is
very likely a numeric separator, but a_b might well be part of
an identifier.
Fixes#639.
This was recently fixed in PHP via
310708845f
so we should fix it here as well.
I'm not adding a dedicated test as it will fail until new PHP versions
are released. This is indirectly tested through the php-src tester.
This only implements the token emulation part, it does not yet
handle the indentation stripping.
Emulating this feature on old PHP versions is really tough and is
not going to work perfectly, but hopefully this implementation is
"good enough".
Add ErrorHandler interface, as well as ErrorHandler\Throwing
and ErrorHandler\Collecting. The error handler is passed to
Parser::parse(). This supersedes the throwOnError option.
NameResolver now accepts an ErrorHandler in the ctor.
These were necessary back in the day when we had to emulate some
complex functionality such as nowdoc strings. Now we can simply
directly translate certain token sequences.
The motivation for this change is to avoid preprocessing of the source
code, which would complicate offset-aware error handling inside the
lexer as offsets would no longer be correct.
As these are shared between Php5 and Php7 parsers they should be
in some common place, otherwise we'd have to always reference either
one or the other.
