typo-cln.lua / last modification: 2020-01-30 14:16
if not modules then modules = { } end modules ['typo-cln'] = {
    version   = 1.001,
    comment   = "companion to typo-cln.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

-- This quick and dirty hack took less time than listening to a CD (In
-- this case Dream Theaters' Octavium). Of course extensions will take
-- more time.

local tonumber = tonumber
local utfbyte = utf.byte

local trace_cleaners = false  trackers.register("typesetters.cleaners",         function(v) trace_cleaners = v end)
local trace_autocase = false  trackers.register("typesetters.cleaners.autocase",function(v) trace_autocase = v end)

local report_cleaners = logs.reporter("nodes","cleaners")
local report_autocase = logs.reporter("nodes","autocase")

typesetters.cleaners  = typesetters.cleaners or { }
local cleaners        = typesetters.cleaners

local variables       = interfaces.variables

local nodecodes       = nodes.nodecodes

local enableaction    = nodes.tasks.enableaction

local texsetattribute = tex.setattribute

local nuts            = nodes.nuts

local getattr         = nuts.getattr
local setattr         = nuts.setattr

local setchar         = nuts.setchar

local nextglyph       = nuts.traversers.glyph

local unsetvalue      = attributes.unsetvalue

local glyph_code      = nodecodes.glyph
local uccodes         = characters.uccodes

local a_cleaner       = attributes.private("cleaner")

local resetter = { -- this will become an entry in char-def
    [utfbyte(".")] = true
}

-- Contrary to the casing code we need to keep track of a state.
-- We could extend the casing code with a status tracker but on
-- the other hand we might want to apply casing afterwards. So,
-- cleaning comes first.

function cleaners.handler(head)
    local inline = false
    for n, char, font in nextglyph, head do
        if resetter[char] then
            inline = false
        elseif not inline then
            local a = getattr(n,a_cleaner)
            if a == 1 then -- currently only one cleaner so no need to be fancy
                local upper = uccodes[char]
                if type(upper) == "table" then
                    -- some day, not much change that \SS ends up here
                else
                    setchar(n,upper)
                    if trace_autocase then
                        report_autocase("")
                    end
                end
            end
            inline = true
        end
    end
    return head
end

-- see typo-cap for a more advanced settings handler .. not needed now

local enabled = false

function cleaners.set(n)
    if n == variables.reset or not tonumber(n) or n == 0 then
        texsetattribute(a_cleaner,unsetvalue)
    else
        if not enabled then
            enableaction("processors","typesetters.cleaners.handler")
            if trace_cleaners then
                report_cleaners("enabling cleaners")
            end
            enabled = true
        end
        texsetattribute(a_cleaner,tonumber(n))
    end
end

-- interface

interfaces.implement {
    name      = "setcharactercleaning",
    actions   = cleaners.set,
    arguments = "string"
}