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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          = nodecodes.glue
40local glyph_code         = nodecodes.glyph
41local hlist_code         = nodecodes.hlist
42local vlist_code         = nodecodes.vlist
43
44local spaceskip_code     = gluecodes.spaceskip
45local xspaceskip_code    = gluecodes.xspaceskip
46
local a_characters       = attributes.private("characters")
48
49local nofreplaced        = 0
50
51-- todo: nbsp etc
52-- todo: collapse kerns (not needed, backend does this)
53-- todo: maybe cache as we now create many nodes
54-- todo: check for subtype related to spacing (13/14 but most seems to be user anyway)
55
56local trace = false   trackers.register("backend.spaces", function(v) trace = v end)
57local slot  = nil
58
59local function injectspaces(head)
60    -- This can become two fast loops or we just move this to the backend where we can
61    -- also check for spaces (it actually is rather old code that relates to tagging
62    -- and so, which was implemented rather early in the mkiv saga). It can also become
63    -- a helper.
64    local p, p_id
65    local n = head
66    while n do
67        local id = getid(n)
68        if id == glue_code then
69            if p and getid(p) == glyph_code then
70                local s = getsubtype(n)
71                if s == spaceskip_code or s == xspaceskip_code then
72                    local g = copy_node(p)
                    local a = getattr(n,a_characters)
74                    setchar(g,slot)
75                    setlink(p,g,n)
76                    setwidth(n,getwidth(n) - getwidth(g)) -- use criterium
77                    if a then
                        setattr(g,a_characters,a)
79                    end
                    setattr(n,a_characters,0)
81                    nofreplaced = nofreplaced + 1
82                end
83            end
84        elseif id == hlist_code or id == vlist_code then
85            injectspaces(getlist(n),slot)
86        end
87        p_id = id
88        p = n
89        n = getnext(n)
90    end
91    return head
92end
93
94nodes.handlers.accessibility = function(head)
95    if trace then
96        if not slot then
97            slot = fonts.helpers.privateslot("visualspace")
98        end
99    else
100        slot = 32
101    end
102    return injectspaces(head,slot)
103end
104
105statistics.register("inserted spaces in output",function()
106    if nofreplaced > 0 then
107        return nofreplaced
108    end
109end)
110