Previously zero-length nop nodes used the lookahead start attributes
and current end attributes. This choice ends up being somewhat weird,
because the end attributes will be the at the last non-whitespace,
non-comment token, which might be quite far back. More problematically,
we may not have encountered any non-discarded token if we're at the
start of the file, in which case we will have no end attributes to
assign.
Change things to use a canonical "zero-length" node representation,
where the end position (token & file) will be exactly one before the
start position.
Fixes#589.
Move doc string parsing logic from rebuildParsers.php and
String_::parseDocString() into ParserAbstract. This stuff is
going to get complicated now.
For now only implement the validation of the indentation on the
end label.
The parser will now always generate Identifier nodes (for
non-namespaced identifiers). This obsoletes the useIdentifierNodes
parser option.
Node constructors still accepts strings and will implicitly create
an Identifier wrapper. Identifier implement __toString(), so that
outside of strict-mode many things continue to work without changes.
Use class_name production and emit the same error as for
"extends self" and "extends parent". It's weird that "extends
static" gives a different result than those two.
The dispatch using $this->{'reduceRule' . $rule}() is very expensive
because it involves
* One allocation when converting $rule to a string
* Another allocation when concatenating the two strings
* Lowercasing during the method call
* Various uncached method checks, e.g. visibility.
Using an array of closures for semantic action dispatch is
significantly more efficient.
We're accessing $this->stackPos a lot, and property accesses are
much more expensive than local variable acesses. Its cheaper to
use a local var and pass it as an argument to semantic actions.
Instead assign attributes on Nop nodes and in the pretty printer
specially handle end<start offsets. It's a somewhat weird case,
but not wrong per se given the meaning the offsets have.
For representing Identifiers that have an implicit leading $.
With this done, maybe go one step further?
* Rename VarLikeIdentifier -> VarIdentifier / VarName
* Use VarIdentifier / VarName also as an inner node in Variable.
Not sure if this adds any real value.
The parameter case is a bit weird, because the subnode is called
"name" here, rather than "var". Nothing we can do about that in
this version though.
The two parser options might be merged. I've kept it separate,
because I think this variable representation should become the
default (or even only representation) in the future, while I'm
less sure about the Identifier thing.
In this mode non-namespaced names that are currently represented
using strings will be represented using Identifier nodes instead.
Identifier nodes have a string $name subnode and coerce to string.
This allows preserving attributes and in particular location
information on identifiers.
Nearly all special errors are now handled gracefully, i.e. the
parser will be able to continue after encountering them. In some
cases the associated error range has been improved using the new
end attribute stack.
To achieve this the error handling code has been moved out of the
node constructors and into special methods in the parser.
It's likely that an error after -> will trigger another one due to
missing semicolon without shifting a single token. We prevent an
immediate failure in this case by manually setting errorState to 2,
which will suppress the duplicate error message, but allow error
recovery.
