Expr\List will now contain ArrayItems instead of plain variables.
I'm reusing ArrayItem, because code handling list() must also handle
arrays, and this allows both to go through the same code path.
This also renames Expr\List->vars to ->items.
TODO: Should Expr\List be dropped in favor of Expr\Array with an
extra flag?
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.
To distinguish array() and [] syntax. The pretty printer respects
this attribute. The shortArraySyntax pretty printer option acts as
a default in case the attribute is not specified.
Kind specifies whether the number was formatted as decimal, octal,
binary or hex. The pretty printer reproduces the number kind (but
not necessarily the exact formatting).
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.
This should be enough for all cases, because: A double has 53 bits
of mantissa (including the implicit 1 bit), which is 53*ln(2)/ln(10)
= 15.95 decimal digits. However the leading decimal digit may encode
less than the usual 3.32 bits, which will push this over the edge to
requiring 17 decimal digits.
This adds an additional "returnType" subnode to Stmt\Function_,
Stmt\ClassMethod and Expr\Closure, as well as the corresponding
support in the name resolver and pretty printer.
