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if not modules then modules = { } end modules ['node-ini'] = {
version = 1.001,
comment = "companion to node-ini.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
--[[ldx--
<p>Most of the code that had accumulated here is now separated in
modules.</p>
--ldx]]--
-- this module is being reconstructed
local utf = unicode.utf8
local next, type = next, type
local format, concat, match, utfchar = string.format, table.concat, string.match, utf.char
--[[ldx--
<p>Access to nodes is what gives <l n='luatex'/> its power. Here we
implement a few helper functions. These functions are rather optimized.</p>
--ldx]]--
--[[ldx--
<p>When manipulating node lists in <l n='context'/>, we will remove
nodes and insert new ones. While node access was implemented, we did
quite some experiments in order to find out if manipulating nodes
in <l n='lua'/> was feasible from the perspective of performance.</p>
<p>First of all, we noticed that the bottleneck is more with excessive
callbacks (some gets called very often) and the conversion from and to
<l n='tex'/>'s datastructures. However, at the <l n='lua'/> end, we
found that inserting and deleting nodes in a table could become a
bottleneck.</p>
<p>This resulted in two special situations in passing nodes back to
<l n='tex'/>: a table entry with value <type>false</type> is ignored,
and when instead of a table <type>true</type> is returned, the
original table is used.</p>
<p>Insertion is handled (at least in <l n='context'/> as follows. When
we need to insert a node at a certain position, we change the node at
that position by a dummy node, tagged <type>inline</type> which itself
has_attribute the original node and one or more new nodes. Before we pass
back the list we collapse the list. Of course collapsing could be built
into the <l n='tex'/> engine, but this is a not so natural extension.</p>
<p>When we collapse (something that we only do when really needed), we
also ignore the empty nodes. [This is obsolete!]</p>
--ldx]]--
nodes = nodes or { }
local hlist = node.id('hlist')
local vlist = node.id('vlist')
local glyph = node.id('glyph')
local glue = node.id('glue')
local penalty = node.id('penalty')
local kern = node.id('kern')
local whatsit = node.id('whatsit')
local traverse_id = node.traverse_id
local traverse = node.traverse
local free_node = node.free
local remove_node = node.remove
local insert_node_before = node.insert_before
local insert_node_after = node.insert_after
function nodes.remove(head, current, free_too)
local t = current
head, current = remove_node(head,current)
if t then
if free_too then
free_node(t)
t = nil
else
t.next, t.prev = nil, nil
end
end
return head, current, t
end
function nodes.delete(head,current)
return nodes.remove(head,current,true)
end
nodes.before = insert_node_before
nodes.after = insert_node_after
-- we need to test this, as it might be fixed now
function nodes.before(h,c,n)
if c then
if c == h then
n.next = h
n.prev = nil
h.prev = n
else
local cp = c.prev
n.next = c
n.prev = cp
if cp then
cp.next = n
end
c.prev = n
return h, n
end
end
return n, n
end
function nodes.after(h,c,n)
if c then
local cn = c.next
if cn then
n.next = cn
cn.prev = n
else
n.next = nil
end
c.next = n
n.prev = c
return h, n
end
return n, n
end
-- local h, c = nodes.replace(head,current,new)
-- local c = nodes.replace(false,current,new)
-- local c = nodes.replace(current,new)
function nodes.replace(head,current,new) -- no head returned if false
if not new then
head, current, new = false, head, current
end
local prev, next = current.prev, current.next
if next then
new.next, next.prev = next, new
end
if prev then
new.prev, prev.next = prev, new
end
if head then
if head == current then
head = new
end
free_node(current)
return head, new
else
free_node(current)
return new
end
end
-- will move
local function count(stack,flat)
local n = 0
while stack do
local id = stack.id
if not flat and id == hlist or id == vlist then
local list = stack.list
if list then
n = n + 1 + count(list) -- self counts too
else
n = n + 1
end
else
n = n + 1
end
stack = stack.next
end
return n
end
nodes.count = count
local left, space = lpeg.P("<"), lpeg.P(" ")
nodes.filterkey = left * (1-left)^0 * left * space^0 * lpeg.C((1-space)^0)
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