[racket] 5.3's "mzc optimizer" log-debug, and log "facility" in general

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Thu Aug 30 12:53:50 EDT 2012

(Sorry guys, I should have read ahead in my mailbox. Please disregard.)

On Thu, Aug 30, 2012 at 11:52 AM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> On Thu, Aug 30, 2012 at 9:32 AM, Greg Hendershott
> <greghendershott at gmail.com> wrote:
>> Thanks, Robby.
>> Do you mean I could do something like this?
>> (define (enable-log-output level)
>>   (let ([r (make-log-receiver (current-logger) level)])
>>     (thread
>>      (lambda ()
>>        (let loop ()
>>          (match (sync r)
>>                 [(vector lvl msg v)
>>                  (printf "; [~a] ~a\n" lvl msg)])
>>          (loop))))))
>> (enable-log-output 'debug)
> Yes, I think so.
>> If so, then:
>> 1. I don't see what you mean re being able to do more than string
>> munging. `v' is a continuation-mark-set. Is that the struct you mean?
> Yes, but perhaps this isn't helpful, as you'd need to use you own
> logging macros to put something other than the continuation marks in
> there. Maybe that makes this a non-starter for you.
>> But stipulating I could filter in whatever fashion ...
>> 2. Putting this in every source file doesn't seem practical? I'm
>> talking about doing interactive development, using XREPL's ,log
>> command. Open a file, evaluate it, make some changes, maybe use ,log
>> to tweak the log output level, evaluate, move on to another file. That
>> sort of work-flow.
> IIUC, this is something you'd do instead of using ,log. You can
> require some helper library with the function in it, or probably Eli
> has some way to add more commands or something like that. Or maybe
> even a patch to ,log that'd let you specify a regexp in the case that
> string munging was the best option?
>> 3. I have to ask users of my collections to use code like this, to
>> avoid getting "drowned" in my log-debug output? That doesn't sound
>> good.
> You could designate a specific logger that you log to, instead of
> logging to the current-logger. This would also require you to call you
> own macros, not log-debug and co.
>> ,log already does filtering on one "dimension" ("severity") without
>> touching your source, which is great. It seems odd to have to use
>> per-file code, in order to filter on another dimension ("facility" or
>> "module").
> I don't think there is any per-module requirement.
> Robby
>> On Thu, Aug 30, 2012 at 8:55 AM, Robby Findler
>> <robby at eecs.northwestern.edu> wrote:
>>> On Thu, Aug 30, 2012 at 6:29 AM, Greg Hendershott
>>> <greghendershott at gmail.com> wrote:
>>>> I have some code with copious log-debug calls. Occasionally I set
>>>> ",log debug" to see the output.
>>>> New in 5.3, I'm seeing many dozens of outputs like the following:
>>>> ; [debug] mzc optimizer: inlining: involving: core727 in: unpack728 in
>>>> module: 's3 size: 149 threshold: 320
>>>> These are interleaved with and badly obscuring my own debug output.
>>>> I've been trying to ignore these and live with it the last couple
>>>> weeks, but it's proving difficult.
>>>> 1. Narrow question: Is there a way I can disable the mzc debug output,
>>>> while preserving my own?
>>> You can set up your own log receiver and filter out the messages that
>>> you want (note that you can filter based on racket data structures,
>>> not just string munging as log messages have a value associated with
>>> them that you can query).
>>> Robby

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