1 files changed, 139 insertions, 0 deletions
diff --git a/tex/context/base/mkiv/good-mth.lua b/tex/context/base/mkiv/good-mth.lua
index 7533a17c3..661189350 100644
--- a/tex/context/base/mkiv/good-mth.lua
+++ b/tex/context/base/mkiv/good-mth.lua
@@ -7,6 +7,7 @@ if not modules then modules = { } end modules ['good-mth'] = {
 }
 
 local type, next = type, next
+local ceil = math.ceil
 
 local fonts = fonts
 
@@ -16,6 +17,21 @@ local report_goodies     = logs.reporter("fonts","goodies")
 local registerotffeature = fonts.handlers.otf.features.register
 local fontgoodies        = fonts.goodies or { }
 
+local fontcharacters     = fonts.hashes.characters
+
+local nuts               = nodes.nuts
+
+local setlink            = nuts.setlink
+
+local nodepool           = nuts.pool
+
+local new_kern           = nodepool.kern
+local new_glyph          = nodepool.glyph
+local new_hlist          = nodepool.hlist
+local new_vlist          = nodepool.vlist
+
+local insert_node_after  = nuts.insert_after
+
 -- experiment, we have to load the definitions immediately as they precede
 -- the definition so they need to be initialized in the typescript
 
@@ -171,3 +187,126 @@ registerotffeature {
 }
 
 -- fontgoodies.register("mathitalics", initialize)
+
+local function mathradicalaction(n,h,v,font,mchar,echar)
+    local characters = fontcharacters[font]
+    local mchardata  = characters[mchar]
+    local echardata  = characters[echar]
+    local ewidth     = echardata.width
+    local mwidth     = mchardata.width
+    local delta      = h - ewidth
+    local glyph      = new_glyph(font,echar)
+    local head       = glyph
+    if delta > 0 then
+        local count = ceil(delta/mwidth)
+        local kern  = (delta - count * mwidth) / count
+        for i=1,count do
+            local k = new_kern(kern)
+            local g = new_glyph(font,mchar)
+            setlink(k,head)
+            setlink(g,k)
+            head = g
+        end
+    end
+    local height = mchardata.height
+    local list   = new_hlist(head)
+    local kern   = new_kern(height-v)
+    list = setlink(kern,list)
+    local list = new_vlist(kern)
+    insert_node_after(n,n,list)
+end
+
+local function mathhruleaction(n,h,v,font,bchar,mchar,echar)
+    local characters = fontcharacters[font]
+    local bchardata  = characters[bchar]
+    local mchardata  = characters[mchar]
+    local echardata  = characters[echar]
+    local bwidth     = bchardata.width
+    local mwidth     = mchardata.width
+    local ewidth     = echardata.width
+    local delta      = h - ewidth - bwidth
+    local glyph      = new_glyph(font,echar)
+    local head       = glyph
+    if delta > 0 then
+        local count = ceil(delta/mwidth)
+        local kern  = (delta - count * mwidth) / (count+1)
+        for i=1,count do
+            local k = new_kern(kern)
+            local g = new_glyph(font,mchar)
+            setlink(k,head)
+            setlink(g,k)
+            head = g
+        end
+        local k = new_kern(kern)
+        setlink(k,head)
+        head = k
+    end
+    local g = new_glyph(font,bchar)
+    setlink(g,head)
+    head = g
+    local height = mchardata.height
+    local list   = new_hlist(head)
+    local kern   = new_kern(height-v)
+    list = setlink(kern,list)
+    local list = new_vlist(kern)
+    insert_node_after(n,n,list)
+end
+
+local function initialize(tfmdata)
+    local goodies = tfmdata.goodies
+    if goodies then
+        local resources = tfmdata.resources
+        local ruledata  = { }
+        for i=1,#goodies do
+            local mathematics = goodies[i].mathematics
+            if mathematics then
+                local rules = mathematics.rules
+                if rules then
+                    for tag, name in next, rules do
+                        ruledata[tag] = name
+                    end
+                end
+            end
+        end
+        if next(ruledata) then
+            local characters = tfmdata.characters
+            local unicodes   = resources.unicodes
+            if characters and unicodes then
+                local mathruleactions = resources.mathruleactions
+                if not mathruleactions then
+                    mathruleactions = { }
+                    resources.mathruleactions = mathruleactions
+                end
+                --
+                local mchar = unicodes[ruledata["radical.extender"] or false]
+                local echar = unicodes[ruledata["radical.end"]      or false]
+                if mchar and echar then
+                    mathruleactions.radicalaction = function(n,h,v,font)
+                        mathradicalaction(n,h,v,font,mchar,echar)
+                    end
+                end
+                --
+                local bchar = unicodes[ruledata["hrule.begin"]    or false]
+                local mchar = unicodes[ruledata["hrule.extender"] or false]
+                local echar = unicodes[ruledata["hrule.end"]      or false]
+                if bchar and mchar and echar then
+                    mathruleactions.hruleaction = function(n,h,v,font)
+                        mathhruleaction(n,h,v,font,bchar,mchar,echar)
+                    end
+                end
+                -- not that nice but we need to register it at the tex end
+             -- context.enablemathrules("\\fontclass")
+            end
+        end
+    end
+end
+
+registerotffeature {
+    name         = "mathrules",
+    description  = "check math rules",
+    default      = true,
+    initializers = {
+        base = initialize,
+        node = initialize,
+    }
+}