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|
if not modules then modules = { } end modules ['typo-dir'] = {
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"
}
local next, type = next, type
local format, insert, sub, find, match = string.format, table.insert, string.sub, string.find, string.match
local utfchar = utf.char
-- vertical space handler
local nodes, node = nodes, node
local trace_directions = false trackers.register("typesetters.directions", function(v) trace_directions = v end)
local report_directions = logs.reporter("typesetting","directions")
local has_attribute = node.has_attribute
local unset_attribute = node.unset_attribute
local set_attribute = node.set_attribute
local traverse_id = node.traverse_id
local insert_node_before = node.insert_before
local insert_node_after = node.insert_after
local remove_node = nodes.remove
local texattribute = tex.attribute
local unsetvalue = attributes.unsetvalue
local nodecodes = nodes.nodecodes
local whatcodes = nodes.whatcodes
local mathcodes = nodes.mathcodes
local tasks = nodes.tasks
local glyph_code = nodecodes.glyph
local whatsit_code = nodecodes.whatsit
local math_code = nodecodes.math
local localpar_code = whatcodes.localpar
local dir_code = whatcodes.dir
local nodepool = nodes.pool
local new_textdir = nodepool.textdir
local beginmath_code = mathcodes.beginmath
local endmath_code = mathcodes.endmath
local fonthashes = fonts.hashes
local fontdata = fonthashes.identifiers
local fontchar = fonthashes.characters
local chardata = characters.data
local chardirs = characters.directions -- maybe make a special mirror table
--~ 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
typesetters.directions = typesetters.directions or { }
local directions = typesetters.directions
local a_state = attributes.private('state')
local a_directions = attributes.private('directions')
local skipmath = true
local strip = false
-- todo: delayed inserts here
-- todo: get rid of local functions here
-- beware, math adds whatsits afterwards so that will mess things up
local finish, autodir, embedded, override, done = nil, 0, 0, 0, false
local list, glyphs = nil, false
local finished, finidir, finipos = nil, nil, 1
local head, current, inserted = nil, nil, nil
local function finish_auto_before()
head, inserted = insert_node_before(head,current,new_textdir("-"..finish))
finished, finidir = inserted, finish
if trace_directions then
insert(list,#list,format("auto finish inserted before: %s",finish))
finipos = #list-1
end
finish, autodir, done = nil, 0, true
end
local function finish_auto_after()
head, current = insert_node_after(head,current,new_textdir("-"..finish))
finished, finidir = current, finish
if trace_directions then
list[#list+1] = format("auto finish inserted after: %s",finish)
finipos = #list
end
finish, autodir, done = nil, 0, true
end
local function force_auto_left_before()
if finish then
finish_auto_before()
end
if embedded >= 0 then
finish, autodir, done = "TLT", 1, true
else
finish, autodir, done = "TRT", -1, true
end
if finidir == finish then
head = remove_node(head,finished,true)
if trace_directions then
list[finipos] = list[finipos] .. " (deleted afterwards)"
insert(list,#list,format("start text dir %s (embedded: %s)",finish,embedded))
end
else
head, inserted = insert_node_before(head,current,new_textdir("+"..finish))
if trace_directions then
insert(list,#list,format("start text dir %s (embedded: %s)",finish,embedded))
end
end
end
local function force_auto_right_before()
if finish then
finish_auto_before()
end
if embedded <= 0 then
finish, autodir, done = "TRT", -1, true
else
finish, autodir, done = "TLT", 1, true
end
if finidir == finish then
head = remove_node(head,finished,true)
if trace_directions then
list[finipos] = list[finipos] .. " (deleted afterwards)"
insert(list,#list,format("start text dir %s (embedded: %s)",finish,embedded))
end
else
head, inserted = insert_node_before(head,current,new_textdir("+"..finish))
if trace_directions then
insert(list,#list,format("start text dir %s (embedded: %s)",finish,embedded))
end
end
end
-- todo: use new dir functions
function directions.process(namespace,attribute,start) -- todo: make faster
if not start.next then
return start, false
end
head, current, inserted = start, start, nil
finish, autodir, embedded, override, done = nil, 0, 0, 0, false
list, glyphs = trace_directions and { }, false
finished, finidir, finipos = nil, nil, 1
local stack, top, obsolete = { }, 0, { }
local lro, rlo, prevattr, inmath = false, false, 0, false
while current do
local id = current.id
if skipmath and id == math_code then
local subtype = current.subtype
if subtype == beginmath_code then
inmath = true
elseif subtype == endmath_code then
inmath = false
else
-- todo
end
current = current.next
elseif inmath then
current = current.next
else
local attr = has_attribute(current,attribute)
if attr and attr > 0 then
-- unset_attribute(current,attribute) -- slow, needed?
if attr == 1 then
-- bidi parsing mode
elseif attr ~= prevattr then
-- no pop, grouped driven (2=normal,3=lro,4=rlo)
if attr == 3 then
if trace_directions then
list[#list+1] = format("override right -> left (lro) (bidi=%s)",attr)
end
lro, rlo = true, false
elseif attr == 4 then
if trace_directions then
list[#list+1] = format("override left -> right (rlo) (bidi=%s)",attr)
end
lro, rlo = false, true
else
if trace_directions and
current ~= head then list[#list+1] = format("override reset (bidi=%s)",attr)
end
lro, rlo = false, false
end
prevattr = attr
end
end
if id == glyph_code then
glyphs = true
if attr and attr > 0 then
local char = current.char
local d = chardirs[char]
if rlo or override > 0 then
if d == "l" then
if trace_directions then
list[#list+1] = format("char %s (%s / U+%04X) of class %s overidden to r (bidi=%s)",utfchar(char),char,char,d,attr)
end
d = "r"
elseif trace_directions then
if d == "lro" or d == "rlo" or d == "pdf" then -- else side effects on terminal
list[#list+1] = format("override char of class %s (bidi=%s)",d,attr)
else -- todo: rle lre
list[#list+1] = format("char %s (%s / U+%04X) of class %s (bidi=%s)",utfchar(char),char,char,d,attr)
end
end
elseif lro or override < 0 then
if d == "r" or d == "al" then
set_attribute(current,a_state,4) -- maybe better have a special bidi attr value -> override (9) -> todo
if trace_directions then
list[#list+1] = format("char %s (%s / U+%04X) of class %s overidden to l (bidi=%s) (state=isol)",utfchar(char),char,char,d,attr)
end
d = "l"
elseif trace_directions then
if d == "lro" or d == "rlo" or d == "pdf" then -- else side effects on terminal
list[#list+1] = format("override char of class %s (bidi=%s)",d,attr)
else -- todo: rle lre
list[#list+1] = format("char %s (%s / U+%04X) of class %s (bidi=%s)",utfchar(char),char,char,d,attr)
end
end
elseif trace_directions then
if d == "lro" or d == "rlo" or d == "pdf" then -- else side effects on terminal
list[#list+1] = format("override char of class %s (bidi=%s)",d,attr)
else -- todo: rle lre
list[#list+1] = format("char %s (%s / U+%04X) of class %s (bidi=%s)",utfchar(char),char,char,d,attr)
end
end
if d == "on" then
local mirror = chardata[char].mirror -- maybe make a special mirror table
if mirror and fontchar[current.font][mirror] then
-- todo: set attribute
if autodir < 0 then
current.char = mirror
done = true
--~ elseif left or autodir > 0 then
--~ if not is_right(current.prev) then
--~ current.char = mirror
--~ done = true
--~ end
end
end
elseif d == "l" or d == "en" then -- european number
if autodir <= 0 then -- could be option
force_auto_left_before()
end
elseif d == "r" or d == "al" then -- arabic number
if autodir >= 0 then
force_auto_right_before()
end
elseif d == "an" then -- arabic number
-- actually this is language dependent ...
-- if autodir <= 0 then
-- force_auto_left_before()
-- end
if autodir >= 0 then
force_auto_right_before()
end
elseif d == "lro" then -- Left-to-Right Override -> right becomes left
if trace_directions then
list[#list+1] = "override right -> left"
end
top = top + 1
stack[top] = { override, embedded }
override = -1
obsolete[#obsolete+1] = current
elseif d == "rlo" then -- Right-to-Left Override -> left becomes right
if trace_directions then
list[#list+1] = "override left -> right"
end
top = top + 1
stack[top] = { override, embedded }
override = 1
obsolete[#obsolete+1] = current
elseif d == "lre" then -- Left-to-Right Embedding -> TLT
if trace_directions then
list[#list+1] = "embedding left -> right"
end
top = top + 1
stack[top] = { override, embedded }
embedded = 1
obsolete[#obsolete+1] = current
elseif d == "rle" then -- Right-to-Left Embedding -> TRT
if trace_directions then
list[#list+1] = "embedding right -> left"
end
top = top + 1
stack[top] = { override, embedded }
embedded = -1 -- was 1
obsolete[#obsolete+1] = current
elseif d == "pdf" then -- Pop Directional Format
-- override = 0
if top > 0 then
local s = stack[top]
override, embedded = s[1], s[2]
top = top - 1
if trace_directions then
list[#list+1] = format("state: override: %s, embedded: %s, autodir: %s",override,embedded,autodir)
end
else
if trace_directions then
list[#list+1] = "pop (error, too many pops)"
end
end
obsolete[#obsolete+1] = current
end
elseif trace_directions then
local char = current.char
local d = chardirs[char]
list[#list+1] = format("char %s (%s / U+%04X) of class %s (no bidi)",utfchar(char),char,char,d or "?")
end
elseif id == whatsit_code then
if finish then
finish_auto_before()
end
local subtype = current.subtype
if subtype == localpar_code then
local dir = current.dir
local d = sub(dir,2,2)
if d == 'R' then -- find(dir,".R.") / dir == "TRT"
autodir = -1
else
autodir = 1
end
-- embedded = autodir
if trace_directions then
list[#list+1] = format("pardir %s",dir)
end
elseif subtype == dir_code then
local dir = current.dir
-- local sign = sub(dir,1,1)
-- local dire = sub(dir,3,3)
local sign, dire = match(dir,"^(.).(.)")
if dire == "R" then
if sign == "+" then
finish, autodir = "TRT", -1
else
finish, autodir = nil, 0
end
else
if sign == "+" then
finish, autodir = "TLT", 1
else
finish, autodir = nil, 0
end
end
if trace_directions then
list[#list+1] = format("textdir %s",dir)
end
end
else
if trace_directions then
list[#list+1] = format("node %s (subtype %s)",nodecodes[id],current.subtype)
end
if finish then
finish_auto_before()
end
end
local cn = current.next
if not cn then
if finish then
finish_auto_after()
end
end
current = cn
end
end
if trace_directions and glyphs then
report_directions("start log")
for i=1,#list do
report_directions("%02i: %s",i,list[i])
end
report_directions("stop log")
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 head, done
end
--~ local function is_right(n) -- keep !
--~ if n then
--~ local id = n.id
--~ if id == glyph_code then
--~ local attr = has_attribute(n,attribute)
--~ if attr and attr > 0 then
--~ local d = chardirs[n.char]
--~ if d == "r" or d == "al" then -- override
--~ return true
--~ end
--~ end
--~ end
--~ end
--~ return false
--~ end
--~ function directions.enable()
--~ tasks.enableaction("processors","directions.handler")
--~ end
local enabled = false
function directions.set(n) -- todo: names and numbers
if not enabled then
if trace_directions then
report_breakpoints("enabling directions handler")
end
tasks.enableaction("processors","typesetters.directions.handler")
enabled = true
end
if not n or n == 0 then
n = unsetvalue
-- maybe tracing
end
texattribute[a_directions] = n
end
commands.setdirection = directions.set
directions.handler = nodes.installattributehandler {
name = "directions",
namespace = directions,
processor = directions.process,
}
|