Attempt to restore tlig and co

1 files changed, 334 insertions, 0 deletions

diff --git a/otfl-font-otc.lua b/otfl-font-otc.lua
new file mode 100644
index 0000000..ae463e7
--- /dev/null
+++ b/otfl-font-otc.lua
@@ -0,0 +1,334 @@
+if not modules then modules = { } end modules ['font-otc'] = {
+    version   = 1.001,
+    comment   = "companion to font-otf.lua (context)",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local format, insert = string.format, table.insert
+local type, next = type, next
+local lpegmatch = lpeg.match
+
+-- we assume that the other otf stuff is loaded already
+
+local trace_loading       = false  trackers.register("otf.loading", function(v) trace_loading = v end)
+local report_otf          = logs.reporter("fonts","otf loading")
+
+local fonts               = fonts
+local otf                 = fonts.handlers.otf
+local otffeatures         = fonts.constructors.newfeatures("otf")
+local registerotffeature  = otffeatures.register
+local setmetatableindex   = table.setmetatableindex
+
+-- In the userdata interface we can not longer tweak the loaded font as
+-- conveniently as before. For instance, instead of pushing extra data in
+-- in the table using the original structure, we now have to operate on
+-- the mkiv representation. And as the fontloader interface is modelled
+-- after fontforge we cannot change that one too much either.
+
+local types = {
+    substitution = "gsub_single",
+    ligature     = "gsub_ligature",
+    alternate    = "gsub_alternate",
+}
+
+setmetatableindex(types, function(t,k) t[k] = k return k end) -- "key"
+
+local everywhere = { ["*"] = { ["*"] = true } } -- or: { ["*"] = { "*" } }
+local noflags    = { }
+
+local function addfeature(data,feature,specifications)
+    local descriptions = data.descriptions
+    local resources    = data.resources
+    local lookups      = resources.lookups
+    local gsubfeatures = resources.features.gsub
+    if gsubfeatures and gsubfeatures[feature] then
+        -- already present
+    else
+        local sequences    = resources.sequences
+        local fontfeatures = resources.features
+        local unicodes     = resources.unicodes
+        local lookuptypes  = resources.lookuptypes
+        local splitter     = lpeg.splitter(" ",unicodes)
+        local done         = 0
+        local skip         = 0
+        if not specifications[1] then
+            -- so we accept a one entry specification
+            specifications = { specifications }
+        end
+        -- subtables are tables themselves but we also accept flattened singular subtables
+        for s=1,#specifications do
+            local specification = specifications[s]
+            local valid         = specification.valid
+            if not valid or valid(data,specification,feature) then
+                local initialize = specification.initialize
+                if initialize then
+                    -- when false is returned we initialize only once
+                    specification.initialize = initialize(specification) and initialize or nil
+                end
+                local askedfeatures = specification.features or everywhere
+                local subtables     = specification.subtables or { specification.data } or { }
+                local featuretype   = types[specification.type or "substitution"]
+                local featureflags  = specification.flags or noflags
+                local added         = false
+                local featurename   = format("ctx_%s_%s",feature,s)
+                local st = { }
+                for t=1,#subtables do
+                    local list = subtables[t]
+                    local full = format("%s_%s",featurename,t)
+                    st[t] = full
+                    if featuretype == "gsub_ligature" then
+                        lookuptypes[full] = "ligature"
+                        for code, ligature in next, list do
+                            local unicode = tonumber(code) or unicodes[code]
+                            local description = descriptions[unicode]
+                            if description then
+                                local slookups = description.slookups
+                                if type(ligature) == "string" then
+                                    ligature = { lpegmatch(splitter,ligature) }
+                                end
+                                local present = true
+                                for i=1,#ligature do
+                                    if not descriptions[ligature[i]] then
+                                        present = false
+                                        break
+                                    end
+                                end
+                                if present then
+                                    if slookups then
+                                        slookups[full] = ligature
+                                    else
+                                        description.slookups = { [full] = ligature }
+                                    end
+                                    done, added = done + 1, true
+                                else
+                                    skip = skip + 1
+                                end
+                            end
+                        end
+                    elseif featuretype == "gsub_single" then
+                        lookuptypes[full] = "substitution"
+                        for code, replacement in next, list do
+                            local unicode = tonumber(code) or unicodes[code]
+                            local description = descriptions[unicode]
+                            if description then
+                                local slookups = description.slookups
+                                replacement = tonumber(replacement) or unicodes[replacement]
+                                if descriptions[replacement] then
+                                    if slookups then
+                                        slookups[full] = replacement
+                                    else
+                                        description.slookups = { [full] = replacement }
+                                    end
+                                    done, added = done + 1, true
+                                end
+                            end
+                        end
+                    end
+                end
+                if added then
+                    -- script = { lang1, lang2, lang3 } or script = { lang1 = true, ... }
+                    for k, v in next, askedfeatures do
+                        if v[1] then
+                            askedfeatures[k] = table.tohash(v)
+                        end
+                    end
+                    sequences[#sequences+1] = {
+                        chain     = 0,
+                        features  = { [feature] = askedfeatures },
+                        flags     = featureflags,
+                        name      = featurename,
+                        subtables = st,
+                        type      = featuretype,
+                    }
+                    -- register in metadata (merge as there can be a few)
+                    if not gsubfeatures then
+                        gsubfeatures  = { }
+                        fontfeatures.gsub = gsubfeatures
+                    end
+                    local k = gsubfeatures[feature]
+                    if not k then
+                        k = { }
+                        gsubfeatures[feature] = k
+                    end
+                    for script, languages in next, askedfeatures do
+                        local kk = k[script]
+                        if not kk then
+                            kk = { }
+                            k[script] = kk
+                        end
+                        for language, value in next, languages do
+                            kk[language] = value
+                        end
+                    end
+                end
+            end
+        end
+        if trace_loading then
+            report_otf("enhance: registering feature '%s', %s glyphs affected, %s glyphs skipped",feature,done,skip)
+        end
+    end
+end
+
+otf.enhancers.addfeature = addfeature
+
+local extrafeatures = { }
+
+function otf.addfeature(name,specification)
+    extrafeatures[name] = specification
+end
+
+local function enhance(data,filename,raw)
+    for feature, specification in next, extrafeatures do
+        addfeature(data,feature,specification)
+    end
+end
+
+otf.enhancers.register("check extra features",enhance)
+
+-- tlig --
+
+local tlig = {
+    endash        = "hyphen hyphen",
+    emdash        = "hyphen hyphen hyphen",
+ -- quotedblleft  = "quoteleft quoteleft",
+ -- quotedblright = "quoteright quoteright",
+ -- quotedblleft  = "grave grave",
+ -- quotedblright = "quotesingle quotesingle",
+ -- quotedblbase  = "comma comma",
+}
+
+local tlig_specification = {
+    type     = "ligature",
+    features = everywhere,
+    data     = tlig,
+    flags    = noflags,
+}
+
+otf.addfeature("tlig",tlig_specification)
+
+registerotffeature {
+    name        = 'tlig',
+    description = 'tex ligatures',
+}
+
+-- trep
+
+local trep = {
+ -- [0x0022] = 0x201D,
+    [0x0027] = 0x2019,
+ -- [0x0060] = 0x2018,
+}
+
+local trep_specification = {
+    type      = "substitution",
+    features  = everywhere,
+    data      = trep,
+    flags     = noflags,
+}
+
+otf.addfeature("trep",trep_specification)
+
+registerotffeature {
+    name        = 'trep',
+    description = 'tex replacements',
+}
+
+-- tcom
+
+if characters.combined then
+
+    local tcom = { }
+
+    local function initialize()
+        characters.initialize()
+        for first, seconds in next, characters.combined do
+            for second, combination in next, seconds do
+                tcom[combination] = { first, second }
+            end
+        end
+        -- return false
+    end
+
+    local tcom_specification = {
+        type       = "ligature",
+        features   = everywhere,
+        data       = tcom,
+        flags      = noflags,
+        initialize = initialize,
+    }
+
+    otf.addfeature("tcom",tcom_specification)
+
+    registerotffeature {
+        name        = 'tcom',
+        description = 'tex combinations',
+    }
+
+end
+
+-- anum
+
+local anum_arabic = {
+    [0x0030] = 0x0660,
+    [0x0031] = 0x0661,
+    [0x0032] = 0x0662,
+    [0x0033] = 0x0663,
+    [0x0034] = 0x0664,
+    [0x0035] = 0x0665,
+    [0x0036] = 0x0666,
+    [0x0037] = 0x0667,
+    [0x0038] = 0x0668,
+    [0x0039] = 0x0669,
+}
+
+local anum_persian = {
+    [0x0030] = 0x06F0,
+    [0x0031] = 0x06F1,
+    [0x0032] = 0x06F2,
+    [0x0033] = 0x06F3,
+    [0x0034] = 0x06F4,
+    [0x0035] = 0x06F5,
+    [0x0036] = 0x06F6,
+    [0x0037] = 0x06F7,
+    [0x0038] = 0x06F8,
+    [0x0039] = 0x06F9,
+}
+
+local function valid(data)
+    local features = data.resources.features
+    if features then
+        for k, v in next, features do
+            for k, v in next, v do
+                if v.arab then
+                    return true
+                end
+            end
+        end
+    end
+end
+
+local anum_specification = {
+    {
+        type     = "substitution",
+        features = { arab = { URD = true, dflt = true } },
+        data     = anum_arabic,
+        flags    = noflags, -- { },
+        valid    = valid,
+    },
+    {
+        type     = "substitution",
+        features = { arab = { URD = true } },
+        data     = anum_persian,
+        flags    = noflags, -- { },
+        valid    = valid,
+    },
+}
+
+otf.addfeature("anum",anum_specification) -- todo: only when there is already an arab script feature
+
+registerotffeature {
+    name        = 'anum',
+    description = 'arabic digits',
+}