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Diffstat (limited to 'tex/context/base/mkiv/typo-dir.lua')
| -rw-r--r-- | tex/context/base/mkiv/typo-dir.lua | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/tex/context/base/mkiv/typo-dir.lua b/tex/context/base/mkiv/typo-dir.lua new file mode 100644 index 000000000..482b7114d --- /dev/null +++ b/tex/context/base/mkiv/typo-dir.lua @@ -0,0 +1,207 @@ +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" +} + +-- When we started with this, there were some issues in luatex so we needed to take care of +-- intereferences. Some has been improved but we stil might end up with each node having a +-- dir property. Now, the biggest problem is that there is an official bidi algorithm but +-- some searching on the web shows that there are many confusing aspects and therefore +-- proposals circulate about (sometimes imcompatible ?) improvements. In the end it all boils +-- down to the lack of willingness to tag an input source. Of course tagging of each number +-- and fenced strip is somewhat over the top, but now it has to be captured in logic. Texies +-- normally have no problem with tagging but we need to handle any input. So, what we have +-- done here (over the years) is starting from what we expect to see happen, especially with +-- respect to punctation, numbers and fences. Eventually alternative algorithms will be provides +-- so that users can choose (the reason why suggestion sfor improvements circulate on the web +-- is that it is non trivial to predict the expected behaviour so one hopes that the ditor +-- and the rest of the machinery match somehow. Anyway, the fun of tex is that it has no hard +-- coded behavior. And ... we also want to have more debugging and extras and ... so we want +-- a flexible approach. In the end we will have: +-- +-- = full tagging (mechanism turned off) +-- = half tagging (the current implementation) +-- = unicode version x interpretation (several depending on the evolution) + +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 +local formatters = string.formatters + +local nodes, node = nodes, node + +local trace_textdirections = false trackers.register("typesetters.directions.text", function(v) trace_textdirections = v end) +local trace_mathdirections = false trackers.register("typesetters.directions.math", function(v) trace_mathdirections = v end) +local trace_directions = false trackers.register("typesetters.directions", function(v) trace_textdirections = v trace_mathdirections = v end) + +local report_textdirections = logs.reporter("typesetting","text directions") +local report_mathdirections = logs.reporter("typesetting","math directions") + +local hasbit = number.hasbit + +local texsetattribute = tex.setattribute +local unsetvalue = attributes.unsetvalue + +local tasks = nodes.tasks +local tracers = nodes.tracers +local setcolor = tracers.colors.set +local resetcolor = tracers.colors.reset + +local implement = interfaces.implement + +local directions = typesetters.directions or { } +typesetters.directions = directions + +local a_directions = attributes.private('directions') + +local variables = interfaces.variables +local v_global = variables["global"] +local v_local = variables["local"] +local v_on = variables.on +local v_yes = variables.yes + +local m_enabled = 2^6 -- 64 +local m_global = 2^7 +local m_fences = 2^8 + +local handlers = { } +local methods = { } +local lastmethod = 0 + +local function installhandler(name,handler) + local method = methods[name] + if not method then + lastmethod = lastmethod + 1 + method = lastmethod + methods[name] = method + end + handlers[method] = handler + return method +end + +directions.handlers = handlers +directions.installhandler = installhandler + +local function tomode(specification) + local scope = specification.scope + local mode + if scope == v_global or scope == v_on then + mode = m_enabled + m_global + elseif scope == v_local then + mode = m_enabled + else + return 0 + end + local method = methods[specification.method] + if method then + mode = mode + method + else + return 0 + end + if specification.fences == v_yes then + mode = mode + m_fences + end + return mode +end + +local function getglobal(a) + return a and a > 0 and hasbit(a,m_global) +end + +local function getfences(a) + return a and a > 0 and hasbit(a,m_fences) +end + +local function getmethod(a) + return a and a > 0 and a % m_enabled or 0 +end + +directions.tomode = tomode +directions.getglobal = getglobal +directions.getfences = getfences +directions.getmethod = getmethod +directions.installhandler = installhandler + +-- beware: in dha we have character properties and in dua|b we have direction properties + +function directions.setcolor(current,direction,reversed,mirror) + if mirror then + setcolor(current,"bidi:mirrored") + elseif direction == "l" then + setcolor(current,reversed and "bidi:left:reversed" or "bidi:left:original") + elseif direction == "r" then + setcolor(current,reversed and "bidi:right:reversed" or "bidi:right:original") + else + resetcolor(current) + end +end + +implement { + name = "getbidimode", + actions = { tomode, context }, + arguments = { + { + { "scope" }, + { "method" }, + { "fences" }, + } + } +} + +local enabled = false + +local starttiming = statistics.starttiming +local stoptiming = statistics.stoptiming + +function directions.handler(head) -- ,_,_,_,direction) -- nodes not nuts | 5th arg is direction + if not head.next then + return head, false + end + local attr = head[a_directions] + if not attr or attr == 0 then + return head, false + end + local method = getmethod(attr) + local handler = handlers[method] + if not handler then + return head, false + end + starttiming(directions) + local head, done = handler(head) + stoptiming(directions) + return head, done +end + +statistics.register("text directions", function() + if enabled then + return statistics.elapsedseconds(directions) + end +end) + +-- function directions.enable() +-- tasks.enableaction("processors","directions.handler") +-- end + +function directions.set(n) -- todo: names and numbers + if not enabled then + if trace_textdirections then + report_textdirections("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 + texsetattribute(a_directions,n) +end + +implement { + name = "setdirection", + arguments = "integer", + actions = directions.set +} |