wide finder?

[PA <petite.abeille@...>]

Hello,

What would be an effective way to implement Tim Bray's Wide Finder in 
Lua?

http://www.tbray.org/ongoing/When/200x/2007/09/20/Wide-Finder
http://www.tbray.org/tmp/o10k.ap

Here is a rather slow implementation:

local aMap = {}
local aList = {}

for aPage in io.read( '*a' ):gmatch( 'GET /ongoing/When/200x/([^%.]+) ' 
) do
    aMap[ aPage ] = ( aMap[ aPage ] or 0 ) + 1
end

for aPage, aCount in pairs( aMap ) do
    aList[ #aList + 1 ] = { aCount, aPage }
end

table.sort( aList, function( first, second ) return first[ 1 ] > 
second[ 1 ] end )

for anIndex = 1, 10 do
    print( aList[ anIndex ][ 1 ], aList[ anIndex ][ 2 ] )
end

LuaProfiler reports that the above Lua implementation is spending it's 
time as follow:

gmatch 60%
read   23%
sort   15%

-- Naive Lua implementation
% /usr/bin/time lua widefinder.lua < o10k.txt
        0.42 real         0.32 user         0.05 sys

-- Tim Bray ruby implementation
% /usr/bin/time ruby widefinder.rb < o10k.txt
        0.18 real         0.15 user         0.02 sys

-- Bill de hÓra python implementation
% /usr/bin/time python widefinder.py o10k.txt
        0.27 real         0.16 user         0.07 sys