Fix the dumb LaTeX bibliography

sortedcitations.lua

-- This script attempts to automatically sort the \bibitem{}s in the bibliography of a .tex file according to occurrences of \cite{}.
-- Pretty much everyone wants this, but LaTeX you to use extra files or sort by hand. This is annoying for small projects which only
-- need to use a single .tex file.

-- Assumptions: all \cite{} and \bibitem{} occurrences are in one file; only one \bibitem{} on each line; string.lower() works with 
-- your citation handles.

tfile = [==[ PASTE .tex FILE HERE ]==] -- or use file i/o and io:lines() instead of the first call to gmatch()

local orders, count, lines = {}, 1, {}

for line in tfile:gmatch"[^\r\n]+" do
    for val in line:gmatch"\\cite{([^}]+)}" do
        for v in val:gmatch"[^, ]+" do -- handle multiple citations in one \cite{...}
            v = v:lower() 
            if not orders[v] then
                orders[v] = count
                count = count + 1
            end
        end
    end
    local bib = line:match"\\bibitem{([^}]+)}"
    if bib then
        print(bib)
        lines[bib:lower()] = line
    end
end

local items = {}
for item, order in pairs(orders) do items[order] = item end
for order, item in ipairs(items) do print(lines[item]) end