if not modules then modules = { } end modules ['m-database'] = {
    version   = 1.001,
    comment   = "companion to m-database.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

local sub, gmatch, format = string.sub, string.gmatch, string.format
local concat = table.concat
local lpegpatterns, lpegmatch, lpegsplitat = lpeg.patterns, lpeg.match, lpeg.splitat
local lpegP, lpegC, lpegS, lpegCt = lpeg.P, lpeg.C, lpeg.S, lpeg.Ct
local stripstring = string.strip

-- One also needs to enable context.trace, here we only plug in some code (maybe
-- some day this tracker will also toggle the main context tracer.

local trace_flush = false  trackers.register("module.database.flush", function(v) trace_flush = v end)

local report_database = logs.reporter("database")

buffers.database = buffers.database or { }

local l_tab   = lpegpatterns.tab
local l_space = lpegpatterns.space
local l_comma = lpegpatterns.comma
local l_empty = lpegS("\t\n\r ")^0 * lpegP(-1)

local v_yes   = interfaces.variables.yes

local separators = { -- not interfaced
    tab    = l_tab,
    tabs   = l_tab^1,
    comma  = l_comma,
    space  = l_space,
    spaces = l_space^1,
}

function buffers.database.process(settings)
    local data
    if settings.type == "file" then
        local filename = resolvers.finders.byscheme("any",settings.database)
        data = filename ~= "" and io.loaddata(filename)
        data = data and string.splitlines(data)
    else
        data = buffers.getlines(settings.database)
    end
    if data and #data > 0 then
        if trace_flush then
            context.pushlogger(report_database)
        end
        local separatorchar, quotechar, commentchar = settings.separator, settings.quotechar, settings.commentchar
        local before, after = settings.before or "", settings.after or ""
        local first, last = settings.first or "", settings.last or ""
        local left, right = settings.left or "", settings.right or ""
        local setups = settings.setups or ""
        local strip = settings.strip == v_yes or false
        local command = settings.command
        separatorchar = (not separatorchar and ",") or separators[separatorchar] or separatorchar
        local separator = type(separatorchar) == "string" and lpegS(separatorchar) or separatorchar
        local whatever  = lpegC((1 - separator)^0)
        if quotechar and quotechar ~= "" then
            local quotedata = nil
            for chr in gmatch(quotechar,".") do
                local quotechar = lpegP(chr)
                local quoteword = l_space^0 * quotechar * lpegC((1 - quotechar)^0) * quotechar * l_space^0
                if quotedata then
                    quotedata = quotedata + quoteword
                else
                    quotedata = quoteword
                end
            end
            whatever = quotedata + whatever
        end
        local checker = commentchar ~= "" and lpegS(commentchar)
        local splitter = lpegCt(whatever * (separator * whatever)^0)
        local found = false
        for i=1,#data do
            local line = data[i]
            if not lpegmatch(l_empty,line) and (not checker or not lpegmatch(checker,line)) then
                local list = lpegmatch(splitter,line)
                if not found then
                    if setups ~= "" then
                        context.begingroup()
                        context.setups { setups }
                    end
                    context(before)
                    found = true
                end
                if trace_flush then
                    local result, r = { }, 0
                    r = r + 1 ; result[r] = first
                    for j=1,#list do
                        local str = strip and stripstring(list[j]) or list[j]
                        r = r + 1 ; result[r] = left
                        if command == "" then
                            r = r + 1 ; result[r] = str
                        else
                            r = r + 1 ; result[r] = command
                            r = r + 1 ; result[r] = "{"
                            r = r + 1 ; result[r] = str
                            r = r + 1 ; result[r] = "}"
                        end
                        r = r + 1 ; result[r] = right
                    end
                    r = r + 1 ; result[r] = last
                    context(concat(result))
                else
                    context(first)
                    for j=1,#list do
                        local str = strip and stripstring(list[j]) or list[j]
                        context(left)
                        if command == "" then
                            context(str)
                        else
                            context(command)
                            context(false,str)
                        end
                        context(right)
                    end
                    context(last)
                end
            end
        end
        if found then
            context(after)
            if setups ~= "" then
                context.endgroup()
            end
        end
        if trace_flush then
            context.poplogger()
        end
    else
        -- message
    end
end
