2016-01-12 16:26:00

1 files changed, 450 insertions, 0 deletions

diff --git a/tex/context/base/mkiv/typo-dha.lua b/tex/context/base/mkiv/typo-dha.lua
new file mode 100644
index 000000000..30984a26c
--- /dev/null
+++ b/tex/context/base/mkiv/typo-dha.lua
@@ -0,0 +1,450 @@
+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  : 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)
+
+-- 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 getattr            = nuts.getattr
+local getprop            = nuts.getprop
+
+local setfield           = nuts.setfield
+local setprop            = nuts.setprop
+local setchar            = nuts.setchar
+
+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 mathcodes          = nodes.mathcodes
+
+local glyph_code         = nodecodes.glyph
+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 dir_code           = nodecodes.dir
+local localpar_code      = nodecodes.localpar
+
+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)
+    local n = new_textdir(finish == "TRT" and "-TRT" or "-TLT")
+    setprop(n,"direction",true)
+    return n
+end
+
+local function startdir(finish)
+    local n = new_textdir(finish == "TRT" and "+TRT" or "+TLT")
+    setprop(n,"direction",true)
+    return n
+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
+
+local function process(start)
+
+    local head     = tonut(start) -- we have a global head
+    local current  = head
+    local autodir  = 0
+    local embedded = 0
+    local override = 0
+    local pardir   = 0
+    local textdir  = 0
+    local done     = false
+    local stack    = { }
+    local top      = 0
+    local obsolete = { }
+    local rlo      = false
+    local lro      = false
+    local prevattr = false
+    local fences   = { }
+
+    while current do
+        local id   = getid(current)
+        local next = getnext(current)
+        if id == math_code then
+            current = getnext(end_of_math(next))
+        elseif getprop(current,"direction") then
+            -- this handles unhbox etc
+            current = next
+        else
+            local attr = getattr(current,a_directions)
+            if attr and attr > 0 then
+                if attr ~= prevattr then
+                    if not getglobal(a) then
+                        lro = false
+                        rlo = false
+                    end
+                    prevattr = attr
+                end
+            end
+            if id == glyph_code then
+                if attr and attr > 0 then
+                    local character = getchar(current)
+                    if character == 0 then
+                        -- skip signals
+                        setprop(current,"direction",true)
+                    else
+                        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) -- hm
+                                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
+                                        setchar(current,mirror)
+                                        setprop(current,"direction","r")
+                                    elseif autodir < 0 then
+                                        setchar(current,mirror)
+                                        setprop(current,"direction","r")
+                                    else
+                                        mirror = false
+                                        setprop(current,"direction","l")
+                                    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
+                                        setchar(current,mirror)
+                                        setprop(current,"direction","r")
+                                    else
+                                        setprop(current,"direction","l")
+                                        mirror = false
+                                    end
+                                elseif autodir < 0 then
+                                    setchar(current,mirror)
+                                    setprop(current,"direction","r")
+                                else
+                                    setprop(current,"direction","l")
+                                    mirror = false
+                                end
+                            else
+                                setprop(current,"direction",true)
+                            end
+                            if trace_directions then
+                                setcolor(current,direction,false,mirror)
+                            end
+                        elseif direction == "l" then
+                            if trace_directions then
+                                setcolor(current,"l",reversed)
+                            end
+                            setprop(current,"direction","l")
+                        elseif direction == "r" then
+                            if trace_directions then
+                                setcolor(current,"r",reversed)
+                            end
+                            setprop(current,"direction","r")
+                        elseif direction == "en" then -- european number
+                            if trace_directions then
+                                setcolor(current,"l")
+                            end
+                            setprop(current,"direction","l")
+                        elseif direction == "al" then -- arabic letter
+                            if trace_directions then
+                                setcolor(current,"r")
+                            end
+                            setprop(current,"direction","r")
+                        elseif direction == "an" then -- arabic number
+                            -- needs a better scanner as it can be a float
+                            if trace_directions then
+                                setcolor(current,"l") -- was r
+                            end
+                            setprop(current,"direction","n") -- was r
+                        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 = s[1]
+                                embedded = s[2]
+                                top      = top - 1
+                            else
+                                override = 0
+                                embedded = 0
+                            end
+                            obsolete[#obsolete+1] = current
+                        elseif trace_directions then
+                            setcolor(current)
+                            setprop(current,"direction",true)
+                        else
+                            setprop(current,"direction",true)
+                        end
+                    end
+                else
+                    setprop(current,"direction",true)
+                end
+            elseif id == glue_code then
+                setprop(current,"direction",'g')
+            elseif id == kern_code then
+                setprop(current,"direction",'k')
+            elseif id == dir_code then
+               local dir = getfield(current,"dir")
+                if dir == "+TRT" then
+                    autodir = -1
+                elseif dir == "+TLT" then
+                    autodir = 1
+                elseif dir == "-TRT" or dir == "-TLT" then
+                    if embedded and embedded~= 0 then
+                        autodir = embedded
+                    else
+                        autodir = 0
+                    end
+                else
+                    -- message
+                end
+                textdir = autodir
+                setprop(current,"direction",true)
+            elseif id == 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
+                setprop(current,"direction",true)
+            else
+                setprop(current,"direction",true)
+            end
+            current = next
+        end
+    end
+
+    -- todo: track if really needed
+    -- todo: maybe we need to set the property (as it can be a copied list)
+
+    if done and strip then
+        local n = #obsolete
+        if n > 0 then
+            for i=1,n do
+                remove_node(head,obsolete[i],true)
+            end
+            if trace_directions then
+                report_directions("%s character nodes removed",n)
+            end
+        end
+    end
+
+    local state    = false
+    local last     = false
+    local collapse = true
+    current        = head
+
+    -- todo: textdir
+    -- todo: inject before parfillskip
+
+    while current do
+        local id = getid(current)
+        if id == math_code then
+            -- todo: this might be tricky nesting
+            current = getnext(end_of_math(getnext(current)))
+        else
+            local cp = getprop(current,"direction")
+            if cp == "n" then
+                local swap = state == "r"
+                if swap then
+                    head = insert_node_before(head,current,startdir("TLT"))
+                end
+                setprop(current,"direction",true)
+                while true do
+                    local n = getnext(current)
+                    if n and getprop(n,"direction") == "n" then
+                        current = n
+                        setprop(current,"direction",true)
+                    else
+                        break
+                    end
+                end
+                if swap then
+                    head, current = insert_node_after(head,current,stopdir("TLT"))
+                end
+            elseif cp == "l" then
+                if state ~= "l" then
+                    if state == "r" then
+                        head = insert_node_before(head,last or current,stopdir("TRT"))
+                    end
+                    head  = insert_node_before(head,current,startdir("TLT"))
+                    state = "l"
+                    done  = true
+                end
+                last  = false
+            elseif cp == "r" then
+                if state ~= "r" then
+                    if state == "l" then
+                        head = insert_node_before(head,last or current,stopdir("TLT"))
+                    end
+                    head  = insert_node_before(head,current,startdir("TRT"))
+                    state = "r"
+                    done  = true
+                end
+                last  = false
+            elseif collapse then
+                if cp == "k" or cp == "g" then
+                    last = last or current
+                else
+                    last = false
+                end
+            else
+                if state == "r" then
+                    head = insert_node_before(head,current,stopdir("TRT"))
+                elseif state == "l" then
+                    head = insert_node_before(head,current,stopdir("TLT"))
+                end
+                state = false
+                last  = false
+            end
+            setprop(current,"direction",true)
+        end
+        local next = getnext(current)
+        if next then
+            current = next
+        else
+            if state == "r" then
+                head = insert_node_after(head,current,stopdir("TRT"))
+            elseif state == "l" then
+                head = insert_node_after(head,current,stopdir("TLT"))
+            end
+            break
+        end
+    end
+
+    return tonode(head), done
+
+end
+
+directions.installhandler(interfaces.variables.default,process)