if not modules then modules = { } end modules ['typo-duc'] = {
version = 1.001,
comment = "companion to typo-dir.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files",
comment = "Unicode bidi (sort of) variant c",
}
-- This is a follow up on typo-uda which itself is a follow up on t-bidi by Khaled Hosny which
-- in turn is based on minibidi.c from Arabeyes. This is a further optimizations, as well as
-- an update on some recent unicode bidi developments. There is (and will) also be more control
-- added. As a consequence this module is somewhat slower than its precursor which itself is
-- slower than the one-pass bidi handler. This is also a playground and I might add some plugin
-- support. However, in the meantime performance got a bit better and this third variant is again
-- some 10% faster than the second variant.
-- todo (cf html):
--
-- normal The element does not offer a additional level of embedding with respect to the bidirectional algorithm. For inline elements implicit reordering works across element boundaries.
-- embed If the element is inline, this value opens an additional level of embedding with respect to the bidirectional algorithm. The direction of this embedding level is given by the direction property.
-- bidi-override For inline elements this creates an override. For block container elements this creates an override for inline-level descendants not within another block container element. This means that inside the element, reordering is strictly in sequence according to the direction property; the implicit part of the bidirectional algorithm is ignored.
-- isolate This keyword indicates that the element's container directionality should be calculated without considering the content of this element. The element is therefore isolated from its siblings. When applying its bidirectional-resolution algorithm, its container element treats it as one or several U+FFFC Object Replacement Character, i.e. like an image.
-- isolate-override This keyword applies the isolation behavior of the isolate keyword to the surrounding content and the override behavior o f the bidi-override keyword to the inner content.
-- plaintext This keyword makes the elements directionality calculated without considering its parent bidirectional state or the value of the direction property. The directionality is calculated using the P2 and P3 rules of the Unicode Bidirectional Algorithm.
-- This value allows to display data which has already formatted using a tool following the Unicode Bidirectional Algorithm.
--
-- todo: check for introduced errors
-- todo: reuse list, we have size, so we can just change values (and auto allocate when not there)
-- todo: reuse the stack
-- todo: no need for a max check
-- todo: collapse bound similar ranges (not ok yet)
-- todo: combine some sweeps
-- todo: removing is not needed when we inject at the same spot (only chnage the dir property)
-- todo: isolated runs (isolating runs are similar to bidi=local in the basic analyzer)
-- todo: check unicode addenda (from the draft):
--
-- Added support for canonical equivalents in BD16.
-- Changed logic in N0 to not check forwards for context in the case of enclosed text opposite the embedding direction.
-- Major extension of the algorithm to allow for the implementation of directional isolates and the introduction of new isolate-related values to the Bidi_Class property.
-- Adds BD8, BD9, BD10, BD11, BD12, BD13, BD14, BD15, and BD16, Sections 2.4 and 2.5, and Rules X5a, X5b, X5c and X6a.
-- Extensively revises Section 3.3.2, Explicit Levels and Directions and its existing X rules to formalize the algorithm for matching a PDF with the embedding or override initiator whose scope it terminates.
-- Moves Rules X9 and X10 into a separate new Section 3.3.3, Preparations for Implicit Processing.
-- Modifies Rule X10 to make the isolating run sequence the unit to which subsequent rules are applied.
-- Modifies Rule W1 to change an NSM preceded by an isolate initiator or PDI into ON.
-- Adds Rule N0 and makes other changes to Section 3.3.5, Resolving Neutral and Isolate Formatting Types to resolve bracket pairs to the same level.
local insert, remove, unpack, concat = table.insert, table.remove, table.unpack, table.concat
local utfchar = utf.char
local setmetatable = setmetatable
local formatters = string.formatters
local directiondata = characters.directions
local mirrordata = characters.mirrors
local textclassdata = characters.textclasses
local nuts = nodes.nuts
local getnext = nuts.getnext
local getid = nuts.getid
local getsubtype = nuts.getsubtype
local getlist = nuts.getlist
local getchar = nuts.getchar
local getattr = nuts.getattr
local getprop = nuts.getprop
local getdirection = nuts.getdirection
local isglyph = nuts.isglyph
local setprop = nuts.setprop
local setchar = nuts.setchar
local setdirection = nuts.setdirection
local setattrlist = nuts.setattrlist
local properties = nodes.properties.data
local remove_node = nuts.remove
local insert_node_after = nuts.insert_after
local insert_node_before = nuts.insert_before
local start_of_par = nuts.start_of_par
local nodepool = nuts.pool
local new_direction = nodepool.direction
local nodecodes = nodes.nodecodes
local gluecodes = nodes.gluecodes
local glyph_code = nodecodes.glyph
local glue_code = nodecodes.glue
local hlist_code = nodecodes.hlist
local vlist_code = nodecodes.vlist
local math_code = nodecodes.math
local dir_code = nodecodes.dir
local localpar_code = nodecodes.localpar
local parfillskip_code = gluecodes.parfillskip
local dirvalues = nodes.dirvalues
local lefttoright_code = dirvalues.lefttoright
local righttoleft_code = dirvalues.righttoleft
local maximum_stack = 0xFF
local a_directions = attributes.private('directions')
local directions = typesetters.directions
local setcolor = directions.setcolor
local getfences = directions.getfences
local remove_controls = true directives.register("typesetters.directions.removecontrols",function(v) remove_controls = v end)
----- analyze_fences = true directives.register("typesetters.directions.analyzefences", function(v) analyze_fences = v end)
local report_directions = logs.reporter("typesetting","directions three")
local trace_directions = false trackers.register("typesetters.directions", function(v) trace_directions = v end)
local trace_details = false trackers.register("typesetters.directions.details", function(v) trace_details = v end)
local trace_list = false trackers.register("typesetters.directions.list", function(v) trace_list = v end)
-- strong (old):
--
-- l : left to right
-- r : right to left
-- lro : left to right override
-- rlo : left to left override
-- lre : left to right embedding
-- rle : left to left embedding
-- al : right to legt arabic (esp punctuation issues)
--
-- weak:
--
-- en : english number
-- es : english number separator
-- et : english number terminator
-- an : arabic number
-- cs : common number separator
-- nsm : nonspacing mark
-- bn : boundary neutral
--
-- neutral:
--
-- b : paragraph separator
-- s : segment separator
-- ws : whitespace
-- on : other neutrals
--
-- interesting: this is indeed better (and more what we expect i.e. we already use this split
-- in the old original (also these isolates)
--
-- strong (new):
--
-- l : left to right
-- r : right to left
-- al : right to left arabic (esp punctuation issues)
--
-- explicit: (new)
--
-- lro : left to right override
-- rlo : left to left override
-- lre : left to right embedding
-- rle : left to left embedding
-- pdf : pop dir format
-- lri : left to right isolate
-- rli : left to left isolate
-- fsi : first string isolate
-- pdi : pop directional isolate
local whitespace = {
lre = true,
rle = true,
lro = true,
rlo = true,
pdf = true,
bn = true,
ws = true,
}
local b_s_ws_on = {
b = true,
s = true,
ws = true,
on = true
}
-- tracing
local function show_list(list,size,what)
local what = what or "direction"
local joiner = utfchar(0x200C)
local result = { }
for i=1,size do
local entry = list[i]
local character = entry.char
local direction = entry[what]
if character == 0xFFFC then
local first = entry.id
local last = entry.last
local skip = entry.skip
if last then
result[i] = formatters["%-3s:%s %s..%s (%i)"](direction,joiner,nodecodes[first],nodecodes[last],skip or 0)
else
result[i] = formatters["%-3s:%s %s (%i)"](direction,joiner,nodecodes[first],skip or 0)
end
elseif character >= 0x202A and character <= 0x202C then
result[i] = formatters["%-3s:%s %U"](direction,joiner,character)
else
result[i] = formatters["%-3s:%s %c %U"](direction,joiner,character,character)
end
end
return concat(result,joiner .. " | " .. joiner)
end
-- preparation
local function show_done(list,size)
local joiner = utfchar(0x200C)
local result = { }
local format = formatters["<%s>"]
for i=1,size do
local entry = list[i]
local character = entry.char
local begindir = entry.begindir
local enddir = entry.enddir
if begindir then
result[#result+1] = format(begindir)
end
if entry.remove then
-- continue
elseif character == 0xFFFC then
result[#result+1] = format("?")
elseif character == 0x0020 then
result[#result+1] = format(" ")
elseif character >= 0x202A and character <= 0x202C then
result[#result+1] = format(entry.original)
else
result[#result+1] = utfchar(character)
end
if enddir then
result[#result+1] = format(enddir)
end
end
return concat(result,joiner)
end
-- keeping the list and overwriting doesn't save much runtime, only a few percent
-- char is only used for mirror, so in fact we can as well only store it for
-- glyphs only
--
-- tracking what direction is used and skipping tests is not faster (extra kind of
-- compensates gain)
local mt_space = { __index = { char = 0x0020, direction = "ws", original = "ws", level = 0, skip = 0 } }
local mt_lre = { __index = { char = 0x202A, direction = "lre", original = "lre", level = 0, skip = 0 } }
local mt_rle = { __index = { char = 0x202B, direction = "rle", original = "rle", level = 0, skip = 0 } }
local mt_pdf = { __index = { char = 0x202C, direction = "pdf", original = "pdf", level = 0, skip = 0 } }
local mt_object = { __index = { char = 0xFFFC, direction = "on", original = "on", level = 0, skip = 0 } }
local stack = table.setmetatableindex("table") -- shared
local list = { } -- shared
local function build_list(head,where)
-- P1
local current = head
local size = 0
while current do
size = size + 1
local id = getid(current)
local p = properties[current]
if p and p.directions then
-- tricky as dirs can be injected in between
local skip = 0
local last = id
current = getnext(current)
while current do
local id = getid(current)
local p = properties[current]
if p and p.directions then
skip = skip + 1
last = id
current = getnext(current)
else
break
end
end
if id == last then -- the start id
list[size] = setmetatable({ skip = skip, id = id },mt_object)
else
list[size] = setmetatable({ skip = skip, id = id, last = last },mt_object)
end
elseif id == glyph_code then
local chr = getchar(current)
local dir = directiondata[chr]
-- could also be a metatable
list[size] = { char = chr, direction = dir, original = dir, level = 0 }
current = getnext(current)
-- if not list[dir] then list[dir] = true end -- not faster when we check for usage
elseif id == glue_code then -- and how about kern
list[size] = setmetatable({ },mt_space)
current = getnext(current)
elseif id == dir_code then
local dir, pop = getdirection(current)
if dir == lefttoright_code then
list[size] = setmetatable({ },pop and mt_pdf or mt_lre)
elseif dir == righttoleft_code then
list[size] = setmetatable({ },pop and mt_pdf or mt_rle)
else
list[size] = setmetatable({ id = id },mt_object)
end
current = getnext(current)
elseif id == math_code then
local skip = 0
current = getnext(current)
while getid(current) ~= math_code do
skip = skip + 1
current = getnext(current)
end
skip = skip + 1
current = getnext(current)
list[size] = setmetatable({ id = id, skip = skip },mt_object)
else -- disc_code: we assume that these are the same as the surrounding
local skip = 0
local last = id
current = getnext(current)
while n do
local id = getid(current)
if id ~= glyph_code and id ~= glue_code and id ~= dir_code then
skip = skip + 1
last = id
current = getnext(current)
else
break
end
end
if id == last then -- the start id
list[size] = setmetatable({ id = id, skip = skip },mt_object)
else
list[size] = setmetatable({ id = id, skip = skip, last = last },mt_object)
end
end
end
return list, size
end
-- new
-- we could support ( ] and [ ) and such ...
-- ש ) ל ( א 0-0
-- ש ( ל ] א 0-0
-- ש ( ל ) א 2-4
-- ש ( ל [ א ) כ ] 2-6
-- ש ( ל ] א ) כ 2-6
-- ש ( ל ) א ) כ 2-4
-- ש ( ל ( א ) כ 4-6
-- ש ( ל ( א ) כ ) 2-8,4-6
-- ש ( ל [ א ] כ ) 2-8,4-6
local fencestack = table.setmetatableindex("table")
local function resolve_fences(list,size,start,limit)
-- N0: funny effects, not always better, so it's an option
local nofstack = 0
for i=start,limit do
local entry = list[i]
if entry.direction == "on" then
local char = entry.char
local mirror = mirrordata[char]
if mirror then
local class = textclassdata[char]
entry.mirror = mirror
entry.class = class
if class == "open" then
nofstack = nofstack + 1
local stacktop = fencestack[nofstack]
stacktop[1] = mirror
stacktop[2] = i
elseif nofstack == 0 then
-- skip
elseif class == "close" then
while nofstack > 0 do
local stacktop = fencestack[nofstack]
if stacktop[1] == char then
local open = stacktop[2]
local close = i
list[open ].paired = close
list[close].paired = open
break
else
-- do we mirror or not
end
nofstack = nofstack - 1
end
end
end
end
end
end
-- local function test_fences(str)
-- local list = { }
-- for s in string.gmatch(str,".") do
-- local b = utf.byte(s)
-- list[#list+1] = { c = s, char = b, direction = directiondata[b] }
-- end
-- resolve_fences(list,#list,1,#size)
-- inspect(list)
-- end
--
-- test_fences("a(b)c(d)e(f(g)h)i")
-- test_fences("a(b[c)d]")
-- the action
local function get_baselevel(head,list,size,direction)
if direction == lefttoright_code or direction == righttoleft_code then
return direction, true
elseif getid(head) == localpar_code and start_of_par(head) then
direction = getdirection(head)
if direction == lefttoright_code or direction == righttoleft_code then
return direction, true
end
end
-- for old times sake we we handle strings too
if direction == "TLT" then
return lefttoright_code, true
elseif direction == "TRT" then
return righttoleft_code, true
end
-- P2, P3
for i=1,size do
local entry = list[i]
local direction = entry.direction
if direction == "r" or direction == "al" then -- and an ?
return righttoleft_code, true
elseif direction == "l" then
return lefttoright_code, true
end
end
return lefttoright_code, false
end
local function resolve_explicit(list,size,baselevel)
-- if list.rle or list.lre or list.rlo or list.lro then
-- X1
local level = baselevel
local override = "on"
local nofstack = 0
for i=1,size do
local entry = list[i]
local direction = entry.direction
-- X2
if direction == "rle" then
if nofstack < maximum_stack then
nofstack = nofstack + 1
local stacktop = stack[nofstack]
stacktop[1] = level
stacktop[2] = override
level = level + (level % 2 == 1 and 2 or 1) -- least_greater_odd(level)
override = "on"
entry.level = level
entry.direction = "bn"
entry.remove = true
elseif trace_directions then
report_directions("stack overflow at position %a with direction %a",i,direction)
end
-- X3
elseif direction == "lre" then
if nofstack < maximum_stack then
nofstack = nofstack + 1
local stacktop = stack[nofstack]
stacktop[1] = level
stacktop[2] = override
level = level + (level % 2 == 1 and 1 or 2) -- least_greater_even(level)
override = "on"
entry.level = level
entry.direction = "bn"
entry.remove = true
elseif trace_directions then
report_directions("stack overflow at position %a with direction %a",i,direction)
end
-- X4
elseif direction == "rlo" then
if nofstack < maximum_stack then
nofstack = nofstack + 1
local stacktop = stack[nofstack]
stacktop[1] = level
stacktop[2] = override
level = level + (level % 2 == 1 and 2 or 1) -- least_greater_odd(level)
override = "r"
entry.level = level
entry.direction = "bn"
entry.remove = true
elseif trace_directions then
report_directions("stack overflow at position %a with direction %a",i,direction)
end
-- X5
elseif direction == "lro" then
if nofstack < maximum_stack then
nofstack = nofstack + 1
local stacktop = stack[nofstack]
stacktop[1] = level
stacktop[2] = override
level = level + (level % 2 == 1 and 1 or 2) -- least_greater_even(level)
override = "l"
entry.level = level
entry.direction = "bn"
entry.remove = true
elseif trace_directions then
report_directions("stack overflow at position %a with direction %a",i,direction)
end
-- X7
elseif direction == "pdf" then
if nofstack > 0 then
local stacktop = stack[nofstack]
level = stacktop[1]
override = stacktop[2]
nofstack = nofstack - 1
entry.level = level
entry.direction = "bn"
entry.remove = true
elseif trace_directions then
report_directions("stack underflow at position %a with direction %a",
i, direction)
else
report_directions("stack underflow at position %a with direction %a: %s",
i, direction, show_list(list,size))
end
-- X6
else
entry.level = level
if override ~= "on" then
entry.direction = override
end
end
end
-- X8 (reset states and overrides after paragraph)
end
local function resolve_weak(list,size,start,limit,orderbefore,orderafter)
-- W1: non spacing marks get the direction of the previous character
-- if list.nsm then
for i=start,limit do
local entry = list[i]
if entry.direction == "nsm" then
if i == start then
entry.direction = orderbefore
else
entry.direction = list[i-1].direction
end
end
end
-- end
-- W2: mess with numbers and arabic
-- if list.en then
for i=start,limit do
local entry = list[i]
if entry.direction == "en" then
for j=i-1,start,-1 do
local prev = list[j]
local direction = prev.direction
if direction == "al" then
entry.direction = "an"
break
elseif direction == "r" or direction == "l" then
break
end
end
end
end
-- end
-- W3
-- if list.al then
for i=start,limit do
local entry = list[i]
if entry.direction == "al" then
entry.direction = "r"
end
end
-- end
-- W4: make separators number
-- if list.es or list.cs then
-- skip
if false then
for i=start+1,limit-1 do
local entry = list[i]
local direction = entry.direction
if direction == "es" then
if list[i-1].direction == "en" and list[i+1].direction == "en" then
entry.direction = "en"
end
elseif direction == "cs" then
local prevdirection = list[i-1].direction
if prevdirection == "en" then
if list[i+1].direction == "en" then
entry.direction = "en"
end
elseif prevdirection == "an" and list[i+1].direction == "an" then
entry.direction = "an"
end
end
end
else -- only more efficient when we have es/cs
local runner = start + 2
if runner <= limit then
local before = list[start]
local entry = list[start + 1]
local after = list[runner]
while after do
local direction = entry.direction
if direction == "es" then
if before.direction == "en" and after.direction == "en" then
entry.direction = "en"
end
elseif direction == "cs" then
local prevdirection = before.direction
if prevdirection == "en" then
if after.direction == "en" then
entry.direction = "en"
end
elseif prevdirection == "an" and after.direction == "an" then
entry.direction = "an"
end
end
before = current
current = after
after = list[runner]
runner = runner + 1
end
end
end
-- end
-- W5
-- if list.et then
local i = start
while i <= limit do
if list[i].direction == "et" then
local runstart = i
local runlimit = runstart
for i=runstart,limit do
if list[i].direction == "et" then
runlimit = i
else
break
end
end
local rundirection = runstart == start and sor or list[runstart-1].direction
if rundirection ~= "en" then
rundirection = runlimit == limit and orderafter or list[runlimit+1].direction
end
if rundirection == "en" then
for j=runstart,runlimit do
list[j].direction = "en"
end
end
i = runlimit
end
i = i + 1
end
-- end
-- W6
-- if list.es or list.cs or list.et then
for i=start,limit do
local entry = list[i]
local direction = entry.direction
if direction == "es" or direction == "et" or direction == "cs" then
entry.direction = "on"
end
end
-- end
-- W7
for i=start,limit do
local entry = list[i]
if entry.direction == "en" then
local prev_strong = orderbefore
for j=i-1,start,-1 do
local direction = list[j].direction
if direction == "l" or direction == "r" then
prev_strong = direction
break
end
end
if prev_strong == "l" then
entry.direction = "l"
end
end
end
end
local function resolve_neutral(list,size,start,limit,orderbefore,orderafter)
-- N1, N2
for i=start,limit do
local entry = list[i]
if b_s_ws_on[entry.direction] then
-- this needs checking
local leading_direction, trailing_direction, resolved_direction
local runstart = i
local runlimit = runstart
-- for j=runstart,limit do
for j=runstart+1,limit do
if b_s_ws_on[list[j].direction] then
-- runstart = j
runlimit = j
else
break
end
end
if runstart == start then
leading_direction = orderbefore
else
leading_direction = list[runstart-1].direction
if leading_direction == "en" or leading_direction == "an" then
leading_direction = "r"
end
end
if runlimit == limit then
trailing_direction = orderafter
else
trailing_direction = list[runlimit+1].direction
if trailing_direction == "en" or trailing_direction == "an" then
trailing_direction = "r"
end
end
if leading_direction == trailing_direction then
-- N1
resolved_direction = leading_direction
else
-- N2 / does the weird period
resolved_direction = entry.level % 2 == 1 and "r" or "l"
end
for j=runstart,runlimit do
list[j].direction = resolved_direction
end
i = runlimit
end
i = i + 1
end
end
local function resolve_implicit(list,size,start,limit,orderbefore,orderafter,baselevel)
for i=start,limit do
local entry = list[i]
local level = entry.level
local direction = entry.direction
if level % 2 ~= 1 then -- even
-- I1
if direction == "r" then
entry.level = level + 1
elseif direction == "an" or direction == "en" then
entry.level = level + 2
end
else
-- I2
if direction == "l" or direction == "en" or direction == "an" then
entry.level = level + 1
end
end
end
end
local function resolve_levels(list,size,baselevel,analyze_fences)
-- X10
local start = 1
while start < size do
local level = list[start].level
local limit = start + 1
while limit < size and list[limit].level == level do
limit = limit + 1
end
local prev_level = start == 1 and baselevel or list[start-1].level
local next_level = limit == size and baselevel or list[limit+1].level
local orderbefore = (level > prev_level and level or prev_level) % 2 == 1 and "r" or "l"
local orderafter = (level > next_level and level or next_level) % 2 == 1 and "r" or "l"
-- W1 .. W7
resolve_weak(list,size,start,limit,orderbefore,orderafter)
-- N0
if analyze_fences then
resolve_fences(list,size,start,limit)
end
-- N1 .. N2
resolve_neutral(list,size,start,limit,orderbefore,orderafter)
-- I1 .. I2
resolve_implicit(list,size,start,limit,orderbefore,orderafter,baselevel)
start = limit
end
-- L1
for i=1,size do
local entry = list[i]
local direction = entry.original
-- (1)
if direction == "s" or direction == "b" then
entry.level = baselevel
-- (2)
for j=i-1,1,-1 do
local entry = list[j]
if whitespace[entry.original] then
entry.level = baselevel
else
break
end
end
end
end
-- (3)
for i=size,1,-1 do
local entry = list[i]
if whitespace[entry.original] then
entry.level = baselevel
else
break
end
end
-- L4
if analyze_fences then
for i=1,size do
local entry = list[i]
if entry.level % 2 == 1 then -- odd(entry.level)
if entry.mirror and not entry.paired then
entry.mirror = false
end
-- okay
elseif entry.mirror then
entry.mirror = false
end
end
else
for i=1,size do
local entry = list[i]
if entry.level % 2 == 1 then -- odd(entry.level)
local mirror = mirrordata[entry.char]
if mirror then
entry.mirror = mirror
end
end
end
end
end
local stack = { }
local function insert_dir_points(list,size)
-- L2, but no actual reversion is done, we simply annotate where
-- begindir/endddir node will be inserted.
local maxlevel = 0
local toggle = true
for i=1,size do
local level = list[i].level
if level > maxlevel then
maxlevel = level
end
end
for level=0,maxlevel do
local started -- = false
local begindir -- = nil
local enddir -- = nil
local prev -- = nil
if toggle then
begindir = lefttoright_code
enddir = lefttoright_code
toggle = false
else
begindir = righttoleft_code
enddir = righttoleft_code
toggle = true
end
for i=1,size do
local entry = list[i]
if entry.level >= level then
if not started then
entry.begindir = begindir
started = true
end
else
if started then
prev.enddir = enddir
started = false
end
end
prev = entry
end
end
-- make sure to close the run at end of line
local last = list[size]
if not last.enddir then
local n = 0
for i=1,size do
local entry = list[i]
local e = entry.enddir
local b = entry.begindir
if e then
n = n - 1
end
if b then
n = n + 1
stack[n] = b
end
end
if n > 0 then
if trace_list and n > 1 then
report_directions("unbalanced list")
end
last.enddir = stack[n]
end
end
end
-- We flag nodes that can be skipped when we see them again but because whatever
-- mechanism can injetc dir nodes that then are not flagged, we don't flag dir
-- nodes that we inject here.
local function apply_to_list(list,size,head,pardir)
local index = 1
local current = head
if trace_list then
report_directions("start run")
end
while current do
if index > size then
report_directions("fatal error, size mismatch")
break
end
local id = getid(current)
local entry = list[index]
local begindir = entry.begindir
local enddir = entry.enddir
local p = properties[current]
if p then
p.directions = true
else
properties[current] = { directions = true }
end
if id == glyph_code then
local mirror = entry.mirror
if mirror then
setchar(current,mirror)
end
if trace_directions then
local direction = entry.direction
if trace_list then
local original = entry.original
local char = entry.char
local level = entry.level
if direction == original then
report_directions("%2i : %C : %s",level,char,direction)
else
report_directions("%2i : %C : %s -> %s",level,char,original,direction)
end
end
setcolor(current,direction,false,mirror)
end
elseif id == hlist_code or id == vlist_code then
setdirection(current,pardir) -- is this really needed?
elseif id == glue_code then
if enddir and getsubtype(current) == parfillskip_code then
-- insert the last enddir before \parfillskip glue
head = insert_node_before(head,current,new_direction(enddir,true))
enddir = false
end
elseif begindir then
if id == localpar_code and start_of_par(current) then
-- localpar should always be the 1st node
head, current = insert_node_after(head,current,new_direction(begindir))
begindir = nil
end
end
if begindir then
head = insert_node_before(head,current,new_direction(begindir))
end
local skip = entry.skip
if skip and skip > 0 then
for i=1,skip do
current = getnext(current)
local p = properties[current]
if p then
p.directions = true
else
properties[current] = { directions = true }
end
end
end
if enddir then
head, current = insert_node_after(head,current,new_direction(enddir,true))
end
if not entry.remove then
current = getnext(current)
elseif remove_controls then
-- X9
head, current = remove_node(head,current,true)
else
current = getnext(current)
end
index = index + 1
end
if trace_list then
report_directions("stop run")
end
return head
end
-- If needed we can optimize for only_one. There is no need to do anything
-- when it's not a glyph. Otherwise we only need to check mirror and apply
-- directions when it's different from the surrounding. Paragraphs always
-- have more than one node. Actually, we only enter this function when we
-- do have a glyph!
local function process(head,direction,only_one,where)
-- for the moment a whole paragraph property
local attr = getattr(head,a_directions)
local analyze_fences = getfences(attr)
--
local list, size = build_list(head,where)
local baselevel, dirfound = get_baselevel(head,list,size,direction)
if trace_details then
report_directions("analyze: baselevel %a",baselevel == righttoleft_code and "r2l" or "l2r")
report_directions("before : %s",show_list(list,size,"original"))
end
resolve_explicit(list,size,baselevel)
resolve_levels(list,size,baselevel,analyze_fences)
insert_dir_points(list,size)
if trace_details then
report_directions("after : %s",show_list(list,size,"direction"))
report_directions("result : %s",show_done(list,size))
end
return apply_to_list(list,size,head,baselevel)
end
local variables = interfaces.variables
directions.installhandler(variables.one, process) -- for old times sake
directions.installhandler(variables.two, process) -- for old times sake
directions.installhandler(variables.three, process) -- for old times sake
directions.installhandler(variables.unicode,process)
