diff options
Diffstat (limited to 'tex/context/base/typo-dir.lua')
| -rw-r--r-- | tex/context/base/typo-dir.lua | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/tex/context/base/typo-dir.lua b/tex/context/base/typo-dir.lua new file mode 100644 index 000000000..7fae75975 --- /dev/null +++ b/tex/context/base/typo-dir.lua @@ -0,0 +1,453 @@ +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 utf = unicode.utf8 + +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 trace_directions = false trackers.register("typesetters.directions", function(v) trace_directions = v end) + +local report_directions = logs.new("directions") + +local nodes, node = nodes, node + +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 fontdata = fonts.ids +local fontchar = fonts.chr +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 +--~ print(id,attribute,has_attribute(current,attribute)) + 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 + 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_right_before() + force_auto_left_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)",node.type(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 + +function directions.set(n) + if trace_directions then + report_breakpoints("enabling directions handler") + end + tasks.enableaction("processors","typesetters.directions.handler") + function directions.set(n) + texattribute[a_directions] = n == 0 and unsetvalue or n + end + directions.set(n) +end + +directions.handler = nodes.install_attribute_handler { + name = "directions", + namespace = directions, + processor = directions.process, +} |