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.
Previously the pretty printer added unnecessary and odd-looking parentheses
when several operators with the same precedence were chained:
'a' . 'b' . 'c' . 'd' . 'e'
// was printed as
'a' . ('b' . ('c' . ('d' . 'e')))
Another issue reported as part of #39 was that assignments inside closures
were wrapped in parentheses:
function() {
$a = $b;
}
// was printed as
function() {
($a = $b);
}
This was caused by the automatic precedence handling, which just regarded
the closure as an ordinal nested expression.
With the new system the $predenceMap of PrettyPrinterAbstract contains both
precedence and associativity and there is a new method pPrec() which prints
a node taking precedence and associativity into account.
For simpler usage there are additional function pInfixOp(), pPrefixOp() and
pPostfixOp().
Prints not going through pPrec() do not have any precedence handling (fixing
the closure issue).
