beta 2009.05.28 11:23

1 files changed, 186 insertions, 0 deletions

diff --git a/tex/context/base/typo-brk.lua b/tex/context/base/typo-brk.lua
new file mode 100644
index 000000000..d01b9d653
--- /dev/null
+++ b/tex/context/base/typo-brk.lua
@@ -0,0 +1,186 @@
+if not modules then modules = { } end modules ['typo-brk'] = {
+    version   = 1.001,
+    comment   = "companion to typo-brk.tex",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- this code dates from the beginning and is kind of experimental; it
+-- will be optimized and improved soon
+
+local next, type = next, type
+local format = string.format
+
+local has_attribute      = node.has_attribute
+local unset_attribute    = node.unset_attribute
+local set_attribute      = node.set_attribute
+local copy_node          = node.copy
+local insert_node_before = node.insert_before
+local insert_node_after  = node.insert_after
+local make_penalty_node  = nodes.penalty
+local make_glue_node     = nodes.glue
+local make_disc_node     = nodes.disc
+
+local glyph   = node.id("glyph")
+local kern    = node.id("kern")
+
+breakpoints         = breakpoints         or { }
+breakpoints.mapping = breakpoints.mapping or { }
+breakpoints.methods = breakpoints.methods or { }
+breakpoints.enabled = false
+
+storage.register("breakpoints/mapping", breakpoints.mapping, "breakpoints.mapping")
+
+local mapping = breakpoints.mapping
+
+function breakpoints.setreplacement(id,char,kind,before,after,language)
+    local map = mapping[id]
+    if not map then
+        map = { }
+        mapping[id] = map
+    end
+    local cmap = map[char]
+    if not cmap then
+        cmap = { }
+        map[char] = cmap
+    end
+    cmap[language or ""] = { kind or 1, before or 1, after or 1 }
+end
+
+breakpoints.methods[1] = function(head,start)
+    if start.prev and start.next then
+        insert_node_before(head,start,make_penalty_node(10000))
+        insert_node_before(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_penalty_node(0))
+    end
+    return head, start
+end
+breakpoints.methods[2] = function(head,start) -- ( => (-
+    if start.prev and start.next then
+        local tmp = start
+        start = make_disc_node()
+        start.prev, start.next = tmp.prev, tmp.next
+        tmp.prev.next, tmp.next.prev = start, start
+        tmp.prev, tmp.next = nil, nil
+        start.replace = tmp
+        local tmp, hyphen = copy_node(tmp), copy_node(tmp)
+        hyphen.char = languages.prehyphenchar(tmp.lang)
+        tmp.next, hyphen.prev = hyphen, tmp
+        start.post = tmp
+        insert_node_before(head,start,make_penalty_node(10000))
+        insert_node_before(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_penalty_node(10000))
+    end
+    return head, start
+end
+breakpoints.methods[3] = function(head,start) -- ) => -)
+    if start.prev and start.next then
+        local tmp = start
+        start = make_disc_node()
+        start.prev, start.next = tmp.prev, tmp.next
+        tmp.prev.next, tmp.next.prev = start, start
+        tmp.prev, tmp.next = nil, nil
+        start.replace = tmp
+        local tmp, hyphen = copy_node(tmp), copy_node(tmp)
+        hyphen.char = languages.prehyphenchar(tmp.lang)
+        tmp.prev, hyphen.next = hyphen, tmp
+        start.pre = hyphen
+        insert_node_before(head,start,make_penalty_node(10000))
+        insert_node_before(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_penalty_node(10000))
+    end
+    return head, start
+end
+breakpoints.methods[4] = function(head,start) -- - => - - -
+    if start.prev and start.next then
+        local tmp = start
+        start = make_disc_node()
+        start.prev, start.next = tmp.prev, tmp.next
+        tmp.prev.next, tmp.next.prev = start, start
+        tmp.prev, tmp.next = nil, nil
+        -- maybe prehyphenchar etc
+        start.pre = copy_node(tmp)
+        start.post = copy_node(tmp)
+        start.replace = tmp
+        insert_node_before(head,start,make_penalty_node(10000))
+        insert_node_before(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_glue_node(0))
+        insert_node_after(head,start,make_penalty_node(10000))
+    end
+    return head, start
+end
+
+function breakpoints.process(namespace,attribute,head)
+    local done, numbers = false,  languages.numbers
+    local start, n = head, 0
+    while start do
+        local id = start.id
+        if id == glyph then
+            local attr = has_attribute(start,attribute)
+            if attr and attr > 0 then
+                unset_attribute(start,attribute) -- maybe test for subtype > 256 (faster)
+                -- look ahead and back n chars
+                local map = mapping[attr]
+                if map then
+                    local cmap = map[start.char]
+                    if cmap then
+                        local smap = cmap[numbers[start.lang]] or cmap[""]
+                        if smap then
+                            if n >= smap[2] then
+                                local m = smap[3]
+                                local next = start.next
+                                while next do -- gamble on same attribute
+                                    local id = next.id
+                                    if id == glyph then -- gamble on same attribute
+                                        if map[next.char] then
+                                            break
+                                        elseif m == 1 then
+                                            local method = breakpoints.methods[smap[1]]
+                                            if method then
+                                                head, start = method(head,start)
+                                                done = true
+                                            end
+                                            break
+                                        else
+                                            m = m - 1
+                                            next = next.next
+                                        end
+                                    elseif id == kern and next.subtype == 0 then
+                                        next = next.next
+                                        -- ignore intercharacter kerning, will go way
+                                    else
+                                        -- we can do clever and set n and jump ahead but ... not now
+                                        break
+                                    end
+                                end
+                            end
+                            n = 0
+                        else
+                            n = n + 1
+                        end
+                    else
+                         n = n + 1
+                    end
+                else
+                    n = 0
+                end
+            end
+        elseif id == kern and start.subtype == 0 then
+            -- ignore intercharacter kerning, will go way
+        else
+            n = 0
+        end
+        start = start.next
+    end
+    return head, done
+end
+
+chars.handle_breakpoints = nodes.install_attribute_handler {
+    name = "breakpoint",
+    namespace = breakpoints,
+    processor = breakpoints.process,
+    }