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if not modules then modules = { } end modules ['typo-dha'] = {
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"
}
-- Some analysis by Idris:
--
-- 1. Assuming the reading- vs word-order distinction (bidi-char types) is governing;
-- 2. Assuming that 'ARAB' represents an actual arabic string in raw input order, not word-order;
-- 3. Assuming that 'BARA' represent the correct RL word order;
--
-- Then we have, with input: LATIN ARAB
--
-- \textdir TLT LATIN ARAB => LATIN BARA
-- \textdir TRT LATIN ARAB => LATIN BARA
-- \textdir TRT LRO LATIN ARAB => LATIN ARAB
-- \textdir TLT LRO LATIN ARAB => LATIN ARAB
-- \textdir TLT RLO LATIN ARAB => NITAL ARAB
-- \textdir TRT RLO LATIN ARAB => NITAL ARAB
-- elseif d == "es" then -- European Number Separator
-- elseif d == "et" then -- European Number Terminator
-- elseif d == "cs" then -- Common Number Separator
-- elseif d == "nsm" then -- Non-Spacing Mark
-- elseif d == "bn" then -- Boundary Neutral
-- elseif d == "b" then -- Paragraph Separator
-- elseif d == "s" then -- Segment Separator
-- elseif d == "ws" then -- Whitespace
-- elseif d == "on" then -- Other Neutrals
-- todo : delayed inserts here
-- todo : get rid of local functions here
-- beware: math adds whatsits afterwards so that will mess things up
-- todo : use new dir functions
-- todo : make faster
-- todo : move dir info into nodes
-- todo : swappable tables and floats i.e. start-end overloads (probably loop in builders)
-- todo : check if we still have crashes in luatex when non-matched (used to be the case)
-- I removed the original tracing code and now use the colorful one. If I ever want to change
-- something I will just inject prints for tracing.
local nodes, node = nodes, node
local trace_directions = false trackers.register("typesetters.directions.default", function(v) trace_directions = v end)
local report_directions = logs.reporter("typesetting","text directions")
local nuts = nodes.nuts
local tonut = nuts.tonut
local tonode = nuts.tonode
local nutstring = nuts.tostring
local getnext = nuts.getnext
local getprev = nuts.getprev
local getfont = nuts.getfont
local getchar = nuts.getchar
local getid = nuts.getid
local getsubtype = nuts.getsubtype
local getlist = nuts.getlist
local getfield = nuts.getfield
local setfield = nuts.setfield
local getattr = nuts.getattr
local getprop = nuts.getprop
local setprop = nuts.setprop
local insert_node_before = nuts.insert_before
local insert_node_after = nuts.insert_after
local remove_node = nuts.remove
local end_of_math = nuts.end_of_math
local nodepool = nuts.pool
local nodecodes = nodes.nodecodes
local whatcodes = nodes.whatcodes
local mathcodes = nodes.mathcodes
local glyph_code = nodecodes.glyph
local whatsit_code = nodecodes.whatsit
local math_code = nodecodes.math
local penalty_code = nodecodes.penalty
local kern_code = nodecodes.kern
local glue_code = nodecodes.glue
local hlist_code = nodecodes.hlist
local vlist_code = nodecodes.vlist
local localpar_code = whatcodes.localpar
local dir_code = whatcodes.dir
local new_textdir = nodepool.textdir
local hasbit = number.hasbit
local formatters = string.formatters
local insert = table.insert
local fonthashes = fonts.hashes
local fontdata = fonthashes.identifiers
local fontchar = fonthashes.characters
local chardirections = characters.directions
local charmirrors = characters.mirrors
local charclasses = characters.textclasses
local directions = typesetters.directions
local setcolor = directions.setcolor
local getglobal = directions.getglobal
local a_state = attributes.private('state')
local a_directions = attributes.private('directions')
local strip = false
local s_isol = fonts.analyzers.states.isol
local function stopdir(finish)
return new_textdir(finish == "TRT" and "-TRT" or "-TLT")
end
local function startdir(finish)
return new_textdir(finish == "TRT" and "+TRT" or "+TLT")
end
local function process(start)
local head = tonut(start) -- we have a global head
local current = head
local inserted = nil
local finish = nil
local autodir = 0
local embedded = 0
local override = 0
local pardir = 0
local textdir = 0
local done = false
local finished = nil
local finidir = nil
local stack = { }
local top = 0
local obsolete = { }
local lro = false
local lro = false
local prevattr = false
local fences = { }
local function finish_auto_before()
head, inserted = insert_node_before(head,current,stopdir(finish))
finished, finidir, autodir = inserted, finish, 0
finish, done = nil, true
end
local function finish_auto_after()
head, current = insert_node_after(head,current,stopdir(finish))
finished, finidir, autodir = current, finish, 0
finish, done = nil, true
end
local function force_auto_left_before(direction)
if finish then
head, inserted = insert_node_before(head,current,stopdir(finish))
finished = inserted
finidir = finish
end
if embedded >= 0 then
finish, autodir = "TLT", 1
else
finish, autodir = "TRT", -1
end
done = true
if finidir == finish then
head = remove_node(head,finished,true)
else
head, inserted = insert_node_before(head,current,startdir(finish))
end
end
local function force_auto_right_before(direction)
if finish then
head, inserted = insert_node_before(head,current,stopdir(finish))
finished = inserted
finidir = finish
end
if embedded <= 0 then
finish, autodir = "TRT", -1
else
finish, autodir = "TLT", 1
end
done = true
if finidir == finish then
head = remove_node(head,finished,true)
else
head, inserted = insert_node_before(head,current,startdir(finish))
end
end
local function nextisright(current)
current = getnext(current)
local id = getid(current)
if id == glyph_code then
local character = getchar(current)
local direction = chardirections[character]
return direction == "r" or direction == "al" or direction == "an"
end
end
local function previsright(current)
current = getprev(current)
local id = getid(current)
if id == glyph_code then
local character = getchar(current)
local direction = chardirections[character]
return direction == "r" or direction == "al" or direction == "an"
end
end
while current do
local id = getid(current)
if id == math_code then
current = getnext(end_of_math(getnext(current)))
else
local attr = getattr(current,a_directions)
if attr and attr > 0 and attr ~= prevattr then
if not getglobal(a) then
lro, rlo = false, false
end
prevattr = attr
end
if id == glyph_code then
if attr and attr > 0 then
local character = getchar(current)
local direction = chardirections[character]
local reversed = false
if rlo or override > 0 then
if direction == "l" then
direction = "r"
reversed = true
end
elseif lro or override < 0 then
if direction == "r" or direction == "al" then
setprop(current,a_state,s_isol)
direction = "l"
reversed = true
end
end
if direction == "on" then
local mirror = charmirrors[character]
if mirror and fontchar[getfont(current)][mirror] then
local class = charclasses[character]
if class == "open" then
if nextisright(current) then
if autodir >= 0 then
force_auto_right_before(direction)
end
setfield(current,"char",mirror)
done = true
elseif autodir < 0 then
setfield(current,"char",mirror)
done = true
else
mirror = false
end
local fencedir = autodir == 0 and textdir or autodir
fences[#fences+1] = fencedir
elseif class == "close" and #fences > 0 then
local fencedir = fences[#fences]
fences[#fences] = nil
if fencedir < 0 then
setfield(current,"char",mirror)
done = true
force_auto_right_before(direction)
else
mirror = false
end
elseif autodir < 0 then
setfield(current,"char",mirror)
done = true
else
mirror = false
end
end
if trace_directions then
setcolor(current,direction,false,mirror)
end
elseif direction == "l" then
if trace_directions then
setcolor(current,"l",reversed)
end
if autodir <= 0 then -- could be option
force_auto_left_before(direction)
end
elseif direction == "r" then
if trace_directions then
setcolor(current,"r",reversed)
end
if autodir >= 0 then
force_auto_right_before(direction)
end
elseif direction == "en" then -- european number
if trace_directions then
setcolor(current,"l")
end
if autodir <= 0 then -- could be option
force_auto_left_before(direction)
end
elseif direction == "al" then -- arabic number
if trace_directions then
setcolor(current,"r")
end
if autodir >= 0 then
force_auto_right_before(direction)
end
elseif direction == "an" then -- arabic number
if trace_directions then
setcolor(current,"r")
end
if autodir >= 0 then
force_auto_right_before(direction)
end
elseif direction == "lro" then -- Left-to-Right Override -> right becomes left
top = top + 1
stack[top] = { override, embedded }
override = -1
obsolete[#obsolete+1] = current
elseif direction == "rlo" then -- Right-to-Left Override -> left becomes right
top = top + 1
stack[top] = { override, embedded }
override = 1
obsolete[#obsolete+1] = current
elseif direction == "lre" then -- Left-to-Right Embedding -> TLT
top = top + 1
stack[top] = { override, embedded }
embedded = 1
obsolete[#obsolete+1] = current
elseif direction == "rle" then -- Right-to-Left Embedding -> TRT
top = top + 1
stack[top] = { override, embedded }
embedded = -1
obsolete[#obsolete+1] = current
elseif direction == "pdf" then -- Pop Directional Format
if top > 0 then
local s = stack[top]
override, embedded = s[1], s[2]
top = top - 1
end
obsolete[#obsolete+1] = current
elseif trace_directions then
setcolor(current)
end
else
-- we do nothing
end
elseif id == whatsit_code then
local subtype = getsubtype(current)
if subtype == localpar_code then
local dir = getfield(current,"dir")
if dir == 'TRT' then
autodir = -1
elseif dir == 'TLT' then
autodir = 1
end
pardir = autodir
textdir = pardir
elseif subtype == dir_code then
-- todo: also treat as lro|rlo and stack
if finish then
finish_auto_before()
end
local dir = getfield(current,"dir")
if dir == "+TRT" then
finish, autodir = "TRT", -1
elseif dir == "-TRT" then
finish, autodir = nil, 0
elseif dir == "+TLT" then
finish, autodir = "TLT", 1
elseif dir == "-TLT" then
finish, autodir = nil, 0
end
textdir = autodir
else
if finish then
finish_auto_before()
end
end
elseif finish then
finish_auto_before()
end
local cn = getnext(current)
if cn then
-- we're okay
elseif finish then
finish_auto_after()
end
current = cn
end
end
if done and strip then
local n = #obsolete
if n > 0 then
for i=1,n do
remove_node(head,obsolete[i],true)
end
report_directions("%s character nodes removed",n)
end
end
return tonode(head), done
end
directions.installhandler(interfaces.variables.default,process)
|