Re: Bug Report: glob qualifier Lm-1 does not work

[Bart Schaefer <schaefer@brasslantern.com>]

On Sep 1,  6:01pm, Peter Stephenson wrote:
} Subject: Re: Bug Report: glob qualifier Lm-1 does not work
}
} In other words, files "less than 1 megabyte" have to be zero.  You'll see
} that it does indeed pick up files of zero size.
} 
} The logic behind the reason is that this makes *(Lm-1), *(Lm1) and
} *(Lm+1) disjunct sets, as you might naively expect (until you worked
} out the implications) [...] although you might have thought it would
} make more sense to round file sizes down rather than up.

I seem to recall that these semantics are intended to produce the same
results as the output of "find" with the same -/+ modifiers.  In my
zsh build tree,

    find . -size 2k -print
    print -l **/*(Lk2)

both ouptut the same 62 files, and with -2 both print the same 219
other files.  If not for that, it might make the most sense to round
to the *nearest* size (or whatever measure) rather than up or down.

E.g. right now if U is a multiplier expressed in bytes for a unit such
as "megabyte" and S is a file size in bytes as read from stat(), zsh
computes

    N = (S + (U - 1)) / U

using long integers so the result is truncated.  Looking for files less
(or greater or equal) X units then compares N to X.  But zsh could do

    N = (S + (U / 2)) / U

and preserve the property of distinct sets while treating files less
than half a megabyte in size as "less than one" megabytes.  However, I'm
not sure that would satisfy anyone either, because users couldd still
be confused as to why three-fourths of a megabyte is not less than one.

As I mentioned before, zsh instead could compare S to (X * U) without
rounding or truncating at all, which is probably what most people are
expecting; but then "files exactly 1 megabyte in size" becomes "too
precise."

Of course the ulitmate question here is, how does one express what
Roy actually intended when he wrote (Lm-1), other than by writing it
out longhand as (L-1048576)?  (And is even that what was intended?)
I think the answer is that you can't.  You must choose a multiplier
based on how precise a comparison you want.