Feature #1395: Steppable Kernel::eval

• Status: Rejected
• Assignee: ko1 (Koichi Sasada)
• Target version: -

[mistergibson (G. Gibson)]

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I could really use a steppable eval in the kernel, or a steppable Kernel::Evaluator class. I think this would be very helpful.
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[marcandre (Marc-Andre Lafortune)]

• Category set to core
• Assignee set to matz (Yukihiro Matsumoto)
• Priority changed from Normal to 3

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=end

[mame (Yusuke Endoh)]

• Status changed from Open to Rejected

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Hi,

I could really use a steppable eval in the kernel, or a steppable Kernel::Evaluator class. I think this would be very helpful.

Sorry for late response, but what's "steppable eval" ?
When you register the Feature ticket, please elaborate your request and
use case you expect.

Guessingly, you may want to use Fiber to stop and restart the execution
explicitly, or set_trace_func to interrupt execution step by step.

I close the ticket once. If neither Fiber or set_trace_func can be used,
please re-register a new ticket with elaboration.

--
Yusuke Endoh [e-mail]
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[coatl (caleb clausen)]

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I can't speak for the OP, but what I imagine was intended is something lower-level and finer-grained than set_trace_func. It should allow you to step through code at the (YARV) virtual instruction level. That is, there'd be a callback which gets called before every virtual instruction with parameters telling you what the virtual instruction was and where you are in the containing method....

It's much too ambitious to consider for the 1.9.2 release but I think its well worth thinking about for later.
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[mame (Yusuke Endoh)]

• Category set to YARV
• Status changed from Rejected to Open
• Assignee changed from matz (Yukihiro Matsumoto) to ko1 (Koichi Sasada)
• Target version set to 3.0

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Hi,

2010/3/26 caleb clausen [e-mail]:

I can't speak for the OP, but what I imagine was intended is something lower-level and finer-grained than set_trace_func. It should allow you to step through code at the (YARV) virtual instruction level. That is, there'd be a callback which gets called before every virtual instruction with parameters telling you what the virtual instruction was and where you are in the containing method....

It's much too ambitious to consider for the 1.9.2 release but I think its well worth thinking about for later.

Hmm, ok. I reopen the ticket with change of the target to 2.0.

But, what purpose is it for? I can't think of no use case else
debugging YARV. Isn't current set_trace_func enough?

--
Yusuke ENDOH [e-mail]
=end

[rocky (Rocky Bernstein)]

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The existing low-level mechanisms in fact do cover this right now. Higher-level tools like debug.rb may need to be adjusted.

There are a couple support issues in Ruby that I think could be addressed slightly better. In particular making more of a distinction between when a RubyVM instruction sequence that refers to a real file versus an evaluated string which now shows up as filename "(eval)". Right now a number of programs will get confused if someone ever creates a Ruby file called "(eval)".

That said, in an experimental debugger that I have been working on (rbdbgr) stepping through eval strings works fine. There are some little bugs on my side. See "set string substitute" in
http://wiki.github.com/rocky/rbdbgr/cool-things

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[coatl (caleb clausen)]

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Assuming Rocky is correct, there's nothing to do; it's been done already. Too bad for me I didn't know about it. Seems like this can be closed now.
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[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned

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=end

[naruse (Yui NARUSE)]

• Project changed from Ruby master to 14
• Category deleted (YARV)
• Target version deleted (3.0)

[naruse (Yui NARUSE)]

• Project changed from 14 to Ruby master

[mame (Yusuke Endoh)]

• Status changed from Assigned to Rejected

Closed by reopener's request. Thanks.

--
Yusuke Endoh [e-mail]