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1if not modules then modules = { } end modules ['node-acc'] = {
2    version   = 1.001,
3    comment   = "companion to node-ini.mkiv",
4    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
5    copyright = "PRAGMA ADE / ConTeXt Development Team",
6    license   = "see context related readme files"
7}
8
9-- see mkiv lua module for some experimental unused code
10
11local nodes, node = nodes, node
12
13local tasks              = nodes.tasks
14
15local nuts               = nodes.nuts
16local tonut              = nodes.tonut
17local tonode             = nodes.tonode
18
19local getid              = nuts.getid
20local getsubtype         = nuts.getsubtype
21local getattr            = nuts.getattr
22local getlist            = nuts.getlist
23local getchar            = nuts.getchar
24local getnext            = nuts.getnext
25
26local setattr            = nuts.setattr
27local setlink            = nuts.setlink
28local setchar            = nuts.setchar
29local getwidth           = nuts.getwidth
30local setwidth           = nuts.setwidth
31
32local nextglyph          = nuts.traversers.glyph
33
34local copy_node          = nuts.copy
35
36local nodecodes          = nodes.nodecodes
37local gluecodes          = nodes.gluecodes
38
39local glue_code          <const> = nodecodes.glue
40local glyph_code         <const> = nodecodes.glyph
41local hlist_code         <const> = nodecodes.hlist
42local vlist_code         <const> = nodecodes.vlist
43
44local spaceskip_code     <const> = gluecodes.spaceskip
45local xspaceskip_code    <const> = gluecodes.xspaceskip
46
47local a_characters       <const> = attributes.private("characters")
48
49local nofreplaced        = 0
50
51local trace = false   trackers.register("backend.contenttostring", function(v) trace = v end)
52local slot  = nil
53
54-- todo : use getnextglyph
55
56local function injectspaces(head)
57    -- This can become two fast loops or we just move this to the backend where we can
58    -- also check for spaces (it actually is rather old code that relates to tagging
59    -- and so, which was implemented rather early in the mkiv saga). It can also become
60    -- a helper.
61    local p, p_id
62    local n = head
63    while n do
64        local id = getid(n)
65        if id == glue_code then
66            if p and getid(p) == glyph_code then
67                local s = getsubtype(n)
68                if s == spaceskip_code or s == xspaceskip_code then
69                    local g = copy_node(p)
70                    local a = getattr(n,a_characters)
71                    setchar(g,slot)
72                    setlink(p,g,n)
73                    setwidth(n,getwidth(n) - getwidth(g)) -- use criterium
74                    if a then
75                        setattr(g,a_characters,a)
76                    end
77                    setattr(n,a_characters,0) -- really? better change s into normal
78                    nofreplaced = nofreplaced + 1
79                end
80            end
81        elseif id == hlist_code or id == vlist_code then
82            injectspaces(getlist(n),slot)
83        end
84        p_id = id
85        p = n
86        n = getnext(n)
87    end
88    return head
89end
90
91nodes.handlers.accessibility = function(head)
92    if trace then
93        if not slot then
94            slot = fonts.helpers.privateslot("visualspace")
95        end
96    else
97        slot = 32
98    end
99    return injectspaces(head,slot)
100end
101
102statistics.register("inserted spaces in output",function()
103    if nofreplaced > 0 then
104        return nofreplaced
105    end
106end)
107