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.
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.
Scalar\String_ and Scalar\Encapsed now have an additional "kind"
attribute, which may be one of:
* String_::KIND_SINGLE_QUOTED
* String_::KIND_DOUBLE_QUOTED
* String_::KIND_NOWDOC
* String_::KIND_HEREDOC
Additionally, if the string kind is one of the latter two, an
attribute "docLabel" is provided, which contains the doc string
label (STR in <<<STR) that was originally used.
The pretty printer will try to take the original kind of the string,
as well as the used doc string label into account.
A Nop statement will be inserted into statement lists if there are
any trailing comments in the list (which would otherwise not be
associated with any node).
The pretty printer output currently still contains a superfluous
newline.
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.
