[racket-dev] massive penalty for (except-in (planet ...) ...) require ?

From: John Clements (clements at brinckerhoff.org)
Date: Thu Feb 17 17:18:51 EST 2011

On Feb 17, 2011, at 2:12 PM, Carl Eastlund wrote:

> I don't know precisely what is going on here, but I know from looking
> at expanded code that straightforward module requires become
> straightforward #%requires, while modifications like renaming wind up
> expanding out each individual binding as a separate #%require.  So it
> seems plausible that except-in, rename-in, etc. might seriously impact
> compile time.

Also, FWIW: this is a hard-link planet package, not a normally installed one.

John

> 
> Carl Eastlund
> 
> On Thu, Feb 17, 2011 at 5:04 PM, John Clements
> <clements at brinckerhoff.org> wrote:
>> Running a particular file has been crushingly slow for me, and I finally traced it down
>> (apparently) to the addition of an "except-in" wrapper around a planet require.  Adding the
>> wrapper changes a consistently sub-1-second compile-and run into a big thrashing
>> memory-fest. Is there some kind of invasive renaming that must occur when an "except-in"
>> annotation is added to a require?
>> 
>> John

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