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if not modules then modules = { } end modules ['strc-tag'] = {
version = 1.001,
comment = "companion to strc-tag.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- This is rather experimental code.
local insert, remove, unpack, concat = table.insert, table.remove, table.unpack, table.concat
local gsub, find, topattern, format = string.gsub, string.find, string.topattern, string.format
local lpegmatch = lpeg.match
local texattribute = tex.attribute
local trace_tags = false trackers.register("structures.tags", function(v) trace_tags = v end)
local report_tags = logs.new("tags")
local attributes, structures = attributes, structures
local a_tagged = attributes.private('tagged')
local a_image = attributes.private('image')
local unsetvalue = attributes.unsetvalue
local codeinjections = backends.codeinjections
local taglist, labels, stack, chain, ids, enabled = { }, { }, { }, { }, { }, false -- no grouping assumed
structures.tags = structures.tags or { }
local tags = structures.tags
tags.taglist = taglist -- can best be hidden
function tags.start(tag,label,detail)
--~ labels[label or tag] = tag
labels[tag] = label ~= "" and label or tag
if detail and detail ~= "" then
tag = tag .. ":" .. detail
end
if not enabled then
codeinjections.enabletags(tags,labels)
enabled = true
end
local n = (ids[tag] or 0) + 1
ids[tag] = n
chain[#chain+1] = tag .. "-" .. n -- insert(chain,tag .. ":" .. n)
local t = #tags + 1
stack[#stack+1] = t -- insert(stack,t)
taglist[t] = { unpack(chain) } -- we can add key values for alt and actualtext if needed
texattribute[a_tagged] = t
return t
end
function tags.stop()
local t = stack[#stack] stack[#stack] = nil -- local t = remove(stack)
if not t then
if trace_tags then
report_tags("ignoring end tag, previous chain: %s",#chain > 0 and concat(chain[#chain]) or "none")
end
t = unsetvalue
else
chain[#chain] = nil -- remove(chain)
end
texattribute[a_tagged] = t
return t
end
function structures.atlocation(str)
local location = gsub(concat(taglist[texattribute[a_tagged]],"-"),"%-%d+","")
return find(location,topattern(str)) ~= nil
end
function tags.handler(head) -- we need a dummy
return head, false
end
statistics.register("structure elements", function()
if enabled then
return format("%s element chains identified",#tags)
else
return nil
end
end)
directives.register("backend.addtags", function(v)
if not enabled then
codeinjections.enabletags(tags,labels)
enabled = true
end
end)
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