gistfile1.lua

local function pack(...)
  return arg
end --function

local function as_table(s)
  return pack(s:byte(1, #s))
end --function

-- Levenshtein distance
local function distance_between_words(t1,t2)
  local l1 = #t1
  local l2 = #t2
  local mt = {}
  local cost = 0
  -- Initial matrix
  for i = 0, l1 do
    mt[i] = {}
    mt[i][0] = i
  end --for
  for j = 0, l2 do
    mt[0][j] = j
  end --for
  for j = 1, l2 do
    for i = 1, l1 do
      if(t1[i] == t2[j])
        then cost = 0
        else cost = 1
      end --if
      mt[i][j] = math.min(
        mt[i-1][j] + 1,     -- insertion
        mt[i][j-1] + 1,     -- deletion
        mt[i-1][j-1] + cost -- substitution
      )
    end --for i
  end --for j
  return mt[l1][l2]
end --function

-- Loads an Unix-like dictionary in words
f = io.open(arg[1],"r")
local words = {}
for line in f:lines() do
  words[#words + 1] = line
end --for


-- KISS
local r = {}
local mine = arg[2]
local mine_as_table = as_table(mine)
for k, w in ipairs(words) do
  r[k] = {w, distance_between_words(mine_as_table, as_table(w))}
end --for

local function r_order(a, b)
  return (a[2] < b[2])
end --function

table.sort(r, r_order)
for _, wc in ipairs(r) do
  print(wc[1], wc[2])
end --for

--[[
-- For each word, this evaluates its distance from every other word
local total = #words
local dist = {}
local t1
local t2
for counter, w1 in pairs(words) do
  print("Done "..(counter/total))
  dist[w1] = {}
  t1 = as_table(w1)
  for _, w2 in pairs(words) do
    if(w2 ~= w1) then
      if(dist[w2]) then -- already computed distances for w2
        dist[w1][w2] = dist[w2][w1]
      else
        t2 = as_table(w2)
        dist[w1][w2] = dist_between_words(t1,t2)
      end --if
    end --if
  end --for w2
end --for w1
--]]

gistfile2.txt

First version:
% time lua test.lua web2 a >! bench
lua test.lua web2 a >| bench  14,72s user 0,19s system 98% cpu 15,166 total
% time lua test.lua web2 albator >! bench
lua test.lua web2 albator >| bench  64,38s user 0,56s system 97% cpu 1:06,72 total

local'ing all functions:
% time lua test.lua web2 a >! bench
lua test.lua web2 a >| bench  14,75s user 0,21s system 97% cpu 15,350 total

Switching to min3:
% time lua test.lua web2 a >! bench
lua test.lua web2 a >| bench  9,83s user 0,15s system 98% cpu 10,150 total

Switching to math.min (slower than min3!):
% time lua test.lua web2 a >! bench
lua test.lua web2 a >| bench  9,94s user 0,15s system 98% cpu 10,259 total