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if not modules then modules = { } end modules ['typo-brk'] = {
version = 1.001,
comment = "companion to typo-brk.tex",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- this code dates from the beginning and is kind of experimental; it
-- will be optimized and improved soon
local next, type = next, type
local format = string.format
local has_attribute = node.has_attribute
local unset_attribute = node.unset_attribute
local set_attribute = node.set_attribute
local copy_node = node.copy
local insert_node_before = node.insert_before
local insert_node_after = node.insert_after
local make_penalty_node = nodes.penalty
local make_glue_node = nodes.glue
local make_disc_node = nodes.disc
local glyph = node.id("glyph")
local kern = node.id("kern")
breakpoints = breakpoints or { }
breakpoints.mapping = breakpoints.mapping or { }
breakpoints.methods = breakpoints.methods or { }
breakpoints.enabled = false
breakpoints.attribute = attributes.private("breakpoint")
storage.register("breakpoints/mapping", breakpoints.mapping, "breakpoints.mapping")
local mapping = breakpoints.mapping
function breakpoints.setreplacement(id,char,kind,before,after,language)
local map = mapping[id]
if not map then
map = { }
mapping[id] = map
end
local cmap = map[char]
if not cmap then
cmap = { }
map[char] = cmap
end
cmap[language or ""] = { kind or 1, before or 1, after or 1 }
end
breakpoints.methods[1] = function(head,start)
if start.prev and start.next then
insert_node_before(head,start,make_penalty_node(10000))
insert_node_before(head,start,make_glue_node(0))
insert_node_after(head,start,make_glue_node(0))
insert_node_after(head,start,make_penalty_node(0))
end
return head, start
end
breakpoints.methods[2] = function(head,start) -- ( => (-
if start.prev and start.next then
local tmp = start
start = make_disc_node()
start.prev, start.next = tmp.prev, tmp.next
tmp.prev.next, tmp.next.prev = start, start
tmp.prev, tmp.next = nil, nil
start.replace = tmp
local tmp, hyphen = copy_node(tmp), copy_node(tmp)
hyphen.char = languages.prehyphenchar(tmp.lang)
tmp.next, hyphen.prev = hyphen, tmp
start.post = tmp
insert_node_before(head,start,make_penalty_node(10000))
insert_node_before(head,start,make_glue_node(0))
insert_node_after(head,start,make_glue_node(0))
insert_node_after(head,start,make_penalty_node(10000))
end
return head, start
end
breakpoints.methods[3] = function(head,start) -- ) => -)
if start.prev and start.next then
local tmp = start
start = make_disc_node()
start.prev, start.next = tmp.prev, tmp.next
tmp.prev.next, tmp.next.prev = start, start
tmp.prev, tmp.next = nil, nil
start.replace = tmp
local tmp, hyphen = copy_node(tmp), copy_node(tmp)
hyphen.char = languages.prehyphenchar(tmp.lang)
tmp.prev, hyphen.next = hyphen, tmp
start.pre = hyphen
insert_node_before(head,start,make_penalty_node(10000))
insert_node_before(head,start,make_glue_node(0))
insert_node_after(head,start,make_glue_node(0))
insert_node_after(head,start,make_penalty_node(10000))
end
return head, start
end
breakpoints.methods[4] = function(head,start) -- - => - - -
if start.prev and start.next then
local tmp = start
start = make_disc_node()
start.prev, start.next = tmp.prev, tmp.next
tmp.prev.next, tmp.next.prev = start, start
tmp.prev, tmp.next = nil, nil
-- maybe prehyphenchar etc
start.pre = copy_node(tmp)
start.post = copy_node(tmp)
start.replace = tmp
insert_node_before(head,start,make_penalty_node(10000))
insert_node_before(head,start,make_glue_node(0))
insert_node_after(head,start,make_glue_node(0))
insert_node_after(head,start,make_penalty_node(10000))
end
return head, start
end
function breakpoints.process(namespace,attribute,head)
local done, numbers = false, languages.numbers
local start, n = head, 0
while start do
local id = start.id
if id == glyph then
local attr = has_attribute(start,attribute)
if attr and attr > 0 then
unset_attribute(start,attribute) -- maybe test for subtype > 256 (faster)
-- look ahead and back n chars
local map = mapping[attr]
if map then
local cmap = map[start.char]
if cmap then
local smap = cmap[numbers[start.lang]] or cmap[""]
if smap then
if n >= smap[2] then
local m = smap[3]
local next = start.next
while next do -- gamble on same attribute
local id = next.id
if id == glyph then -- gamble on same attribute
if map[next.char] then
break
elseif m == 1 then
local method = breakpoints.methods[smap[1]]
if method then
head, start = method(head,start)
done = true
end
break
else
m = m - 1
next = next.next
end
elseif id == kern and next.subtype == 0 then
next = next.next
-- ignore intercharacter kerning, will go way
else
-- we can do clever and set n and jump ahead but ... not now
break
end
end
end
n = 0
else
n = n + 1
end
else
n = n + 1
end
else
n = 0
end
end
elseif id == kern and start.subtype == 0 then
-- ignore intercharacter kerning, will go way
else
n = 0
end
start = start.next
end
return head, done
end
chars.handle_breakpoints = nodes.install_attribute_handler {
name = "breakpoint",
namespace = breakpoints,
processor = breakpoints.process,
}
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