Perl-Critic
handle scoped namespaces
The documentation spells out limitations of PPI::Statement::Package - there is no current support for scoped namespaces or determining the current namespace at a current node.
Here's an example to consider:
print "package here is ", __PACKAGE__, "\n"; # main
package Foo;
print "package here is ", __PACKAGE__, "\n"; # Foo
{
print "package here is ", __PACKAGE__, "\n"; # Foo
package Alpha;
print "package here is ", __PACKAGE__, "\n"; # Alpha
}
print "package here is ", __PACKAGE__, "\n"; # Foo
package Bar;
print "package here is ", __PACKAGE__, "\n"; # Bar
What can we do in PPI to figure out the active namespace at each line?
Currently the user needs to manually write a recursive iterator to keep track
of the scopes. It would be very handy if ::Node objects had a ->namespace
interface -- one common usecase would be to associate our $variable
declarations with a package name (e.g. $VERSION, which several Dist::Zilla
plugins would want to do.)
Idea: while walking the node tree, we "just" need to make a note whenever we see a package statement and record what namespace it is... any later sibling node, or any child node, can be marked as part of this namespace.
If by "marking" you mean actually add information to the tree, we can't because the information could be quite unstable (and it would be mean potentially a lot of extra references)
Can you perhaps clarify "mark"?
Can you perhaps clarify "mark"?
Interface-wise, one should be able to do $node->namespace to find out the effective namespace this (sub)expression is active in.
As to how this would be implemented, I don't know! The easiest thing would be to add an extra field to the node hash, but it might be useful to instead have a reference to the node containing the 'package' statement (if so, they'd have to be weak references of course).
I think the instability you refer to is that nodes can be moved around, so their effective namespace might change -- so, whenever a node is moved, the recorded namespace for it and all children (recursively) would have to be stripped.
It should be sufficient to calculate the namespace lazily - it can be recorded whenever we traverse the tree, but otherwise, only calculated on request, so if a lot of nodes are being moved around, there isn't extra overhead.
I don't know enough about PPI guts to anticipate other problems. Perhaps others can, or it may simply be necessary to start implementing this to find out!
Is there anything special to using the term "namespace" as opposed to "package"? I can imagine having both $node->package (for a PPI::Statement::Package) and $node->package_name (for a string).
