Fuzzy substring match in lua

fuzzy.lua

function fuzzySubstringMatch(str,match,maxDiscrepancies)
    local minIdx
    local minDiscrepancies = 1 / 0
    for idx=1,#str do
        local curIdx = idx
        local discrepancies = 0
        local matchIdx = 1
        while matchIdx <= #match do
            local srcChar,srcCharNext = str:byte(curIdx + matchIdx - 1,curIdx + matchIdx)
            local matchChar,matchCharNext = match:byte(matchIdx,matchIdx + 1)

            if srcChar ~= matchChar then
                discrepancies = discrepancies + 1
                
                if matchChar == srcCharNext then
                    -- addition
                    curIdx = curIdx + 1
                elseif matchCharNext == srcChar then
                    -- deletion
                    curIdx = curIdx - 1
                else
                    -- all other cases treat as substitution
                end
            end

            if discrepancies > maxDiscrepancies then break end

            matchIdx = matchIdx + 1
        end

        if discrepancies <= maxDiscrepancies then
            minDiscrepancies = math.min(minDiscrepancies,discrepancies)
            if minDiscrepancies == discrepancies then
                minIdx = idx
            end
        end
    end

    return minDiscrepancies,minIdx
end