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-rw-r--r--Master/texmf-dist/tex/context/base/attr-neg.lua95
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diff --git a/Master/texmf-dist/tex/context/base/attr-neg.lua b/Master/texmf-dist/tex/context/base/attr-neg.lua
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+if not modules then modules = { } end modules ['attr-neg'] = {
+ version = 1.001,
+ comment = "companion to attr-neg.mkiv",
+ author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+ copyright = "PRAGMA ADE / ConTeXt Development Team",
+ license = "see context related readme files"
+}
+
+-- this module is being reconstructed and code will move to other places
+-- we can also do the nsnone via a metatable and then also se index 0
+
+local format = string.format
+
+
+local attributes, nodes = attributes, nodes
+
+local states = attributes.states
+local tasks = nodes.tasks
+local nodeinjections = backends.nodeinjections
+local settexattribute = tex.setattribute
+local variables = interfaces.variables
+local allocate = utilities.storage.allocate
+local setmetatableindex = table.setmetatableindex
+
+--- negative / positive
+
+attributes.negatives = attributes.negatives or { }
+local negatives = attributes.negatives
+
+local a_negative = attributes.private("negative")
+
+negatives.data = allocate()
+negatives.attribute = a_negative
+
+negatives.registered = allocate {
+ [variables.positive] = 1,
+ [variables.negative] = 2,
+}
+
+local data = negatives.data
+local registered = negatives.registered
+
+local function extender(negatives,key)
+ if key == "none" then
+ local d = data[1]
+ negatives.none = d
+ return d
+ end
+end
+
+local function reviver(data,n)
+ if n == 1 then
+ local d = nodeinjections.positive() -- called once
+ data[1] = d
+ return d
+ elseif n == 2 then
+ local d = nodeinjections.negative() -- called once
+ data[2] = d
+ return d
+ end
+end
+
+setmetatableindex(negatives, extender)
+setmetatableindex(negatives.data, reviver)
+
+negatives.handler = nodes.installattributehandler {
+ name = "negative",
+ namespace = negatives,
+ initializer = states.initialize,
+ finalizer = states.finalize,
+ processor = states.process,
+}
+
+local function register(stamp)
+ return registered[stamp] or registered.positive
+end
+
+local function enable()
+ tasks.enableaction("shipouts","attributes.negatives.handler")
+end
+
+negatives.register = register
+negatives.enable = enable
+
+-- interface
+
+local enabled = false
+
+function commands.triggernegative(stamp)
+ if not enabled then
+ enable()
+ enabled = true
+ end
+ settexattribute(a_negative,register(stamp))
+end