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

From: Carl Eastlund (cce at ccs.neu.edu)
Date: Thu Feb 17 17:12:51 EST 2011

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.

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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