Node hierarchies, and the inspection thereof

Sorry if this belongs in Ruby Core, though I don’t really think it does
since it’s more about writing gems than it is Ruby itself.

I’ve been looking (on and off) for the past several months for a way to
accomplish this topic’s namesake. There are many gems for Ruby 1.8x and
a few that even support earlier previews of 1.9.1, but I haven’t found
any that support the current version (1.9.2) or even the official 1.9.1
release.

For reference, a few of the better-known examples of what I’m looking
for are:

ParseTree - http://rubyforge.org/projects/parsetree/
RubyNode - http://rubynode.rubyforge.org/api.html

I understand that at some point, ‘node.h’ was removed from the public
API. This is one of the reasons that most of these gems don’t support
the current release. So I guess my questions are…

  1. Are there ANY gems out there that have found a way to inspect the
    node hierarchy in 1.9 that I might have missed?

  2. The ruby-debug19 gem seems to get around the missing header files by
    relying on the ruby_core_source gem. I didn’t look at it in much detail,
    but that gem seems to pull in the missing headers directly. That said,
    if one were to take this approach, would it be feasible at all to
    implement the functionality I’m looking for? Or is something missing at
    a much more fundamental level? I’ve tried to hack a proof of concept
    together (several times) and they seem to almost work, but invariably
    seem to end with a segfault. Even the “rb_parser_dump_tree” function in
    the Ruby19 node.c gives me a segfault, though it does make it plainly
    obvious that it was never meant for public consumption.

  3. Is there any resource, in addition to reading the Ruby source code
    itself, that might document the various macros in node.h? I’ve been able
    to figure some of them out but others have me downright stumped. I
    suspect my lack of understanding these macros may be related to the
    inevitable segfaulting of my code (though that still doesn’t explain the
    rb_parser_dump_tree segfaults).

  4. Is this really a big deal? I have some really interesting ideas for
    gems that I’d dearly like to implement, but I’m afraid to bother with
    them because relying on RubyNode or ParseTree would make my work totally
    incompatible with Ruby 1.9. Are people actually using 1.9 in the field
    yet? For example, while Rails 3 does support 1.9.2 officially, is anyone
    actually planning to use it with 1.9 or will the user base be sticking
    with 1.8.7 for the foreseeable future (hopefully long enough for the
    missing node stuff to be added back into 1.9)?

Sorry for the novel. I guess I’m just at a point where I don’t know
whether to shrug off this issue and stick with 1.8; implement it myself;
wait for someone else (or a new version of Ruby); or drop my ideas
altogether (which would be truly disappointing, but is unavoidable if
node inspection is gone forever).

Thanks for the help,
Colin MacKenzie IV

I’ve been looking (on and off) for the past several months for a way to
accomplish this topic’s namesake. There are many gems for Ruby 1.8x and
a few that even support earlier previews of 1.9.1, but I haven’t found
any that support the current version (1.9.2) or even the official 1.9.1
release.

Currently there’s no way to get the nodes of methods with 1.9.{1,2}
It might be added in 1.9.3
You can get to the code by using Method#source_location at times, then
re-parse.
GL!
-r

Roger P. wrote:

I’ve been looking (on and off) for the past several months for a way to
accomplish this topic’s namesake. There are many gems for Ruby 1.8x and
a few that even support earlier previews of 1.9.1, but I haven’t found
any that support the current version (1.9.2) or even the official 1.9.1
release.

Currently there’s no way to get the nodes of methods with 1.9.{1,2}
It might be added in 1.9.3
You can get to the code by using Method#source_location at times, then
re-parse.
GL!
-r

That’s what I suspected, but was hoping I’d just missed something. :frowning:

Any idea what the actual likelihood is of this finding its way into
1.9.3? As mentioned, I’d hate to write code that can’t be brought in
line with the latest release.

Thanks for the help, and also for pointing out Method#source_location.
Maybe I can use RubyNode or some such for 1.8, and fall back to
#source_location in 1.9.x. Not ideal, but better than nothing!

-cm4

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