[fontloader] sync with Context as of 2016-04-11

After some discussion, Hans came up with these extensions to the new
reader. We get access to more items from the hideous “name” table. On
the one hand, this means more brokenness to endure and a less sane
matter to work with. But since our tracker was devoid of font-matching
related bug reports for some time, it’s the right move nonetheless.

In addition to the name table junk, the font loader now also includes
the “version” field in the output of “getinfo()”. It’s meaningless per
se, but it sure helps to distinguish historical bugs from the ones that
matter.

**UNTESTED**

1 files changed, 31 insertions, 15 deletions

diff --git a/src/fontloader/misc/fontloader-font-ots.lua b/src/fontloader/misc/fontloader-font-ots.lua
index 4d5e8ec..d67db6d 100644
--- a/src/fontloader/misc/fontloader-font-ots.lua
+++ b/src/fontloader/misc/fontloader-font-ots.lua
@@ -2716,8 +2716,8 @@ function otf.dataset(tfmdata,font) -- generic variant, overloaded in context
     return rl
 end
 
-local function report_disc(n)
-    report_run("kern: %s > %s",disc,languages.serializediscretionary(disc))
+local function report_disc(what,n)
+    report_run("%s: %s > %s",what,n,languages.serializediscretionary(n))
 end
 
 local function kernrun(disc,k_run,font,attr,...)
@@ -2725,7 +2725,7 @@ local function kernrun(disc,k_run,font,attr,...)
     -- we catch <font 1><disc font 2>
     --
     if trace_kernruns then
-        report_disc("kern")
+        report_disc("kern",disc)
     end
     --
     local prev, next = getboth(disc)
@@ -2819,7 +2819,7 @@ end
 
 local function comprun(disc,c_run,...)
     if trace_compruns then
-        report_disc("comp")
+        report_disc("comp",disc)
     end
     --
     local pre, post, replace = getdisc(disc)
@@ -2866,31 +2866,35 @@ end
 
 local function testrun(disc,t_run,c_run,...)
     if trace_testruns then
-        report_disc("test")
+        report_disc("test",disc)
     end
     local prev, next = getboth(disc)
     if not next then
         -- weird discretionary
         return
     end
-    local pre, post, replace, pretail, posttail, replacetail = getdisc(disc)
+    local pre, post, replace, pretail, posttail, replacetail = getdisc(disc,true)
     local done = false
     if replace and prev then
-        -- only look ahead
-     -- local nest = getprev(replace)
+        -- this is a bit strange as we only do replace here and not post
+        -- anyway, we only look ahead ... the idea is that we discard a
+        -- disc when there is a ligature crossing the replace boundary
         setlink(replacetail,next)
-        if t_run(replace,next,...) then
-            setfield(disc,"replace",nil) -- beware, side effects of nest so first
+        local ok, overflow = t_run(replace,next,...)
+        if ok and overflow then
+            -- so, we can have crossed the boundary
+            setfield(disc,"replace",nil)
             setlink(prev,replace)
-            setlink(replacetail,next)
+         -- setlink(replacetail,next)
             setboth(disc)
             flush_node_list(disc)
             return replace, true -- restart .. tricky !
         else
+            -- we stay inside the disc
             setnext(replacetail)
             setprev(next,disc)
         end
- --       pre, post, replace, pretail, posttail, replacetail = getdisc(disc)
+     -- pre, post, replace, pretail, posttail, replacetail = getdisc(disc,true)
     end
     --
     -- like comprun
@@ -2945,7 +2949,7 @@ end
 -- local function discrun(disc,drun,krun)
 --     local prev, next = getboth(disc)
 --     if trace_discruns then
---        report_disc("disc")
+--        report_disc("disc",disc)
 --     end
 --     if next and prev then
 --         setnext(prev,next)
@@ -3043,7 +3047,13 @@ local function t_run_single(start,stop,font,attr,lookupcache)
                     -- if we need more than ligatures we can outline the code and use functions
                     local s = getnext(start)
                     local l = nil
+                    local d = 0
                     while s do
+                        if s == stop then
+                            d = 1
+                        elseif d > 0 then
+                            d = d + 1
+                        end
                         local lg = lookupmatch[getchar(s)]
                         if lg then
                             l = lg
@@ -3053,7 +3063,7 @@ local function t_run_single(start,stop,font,attr,lookupcache)
                         end
                     end
                     if l and l.ligature then
-                        return true
+                        return true, d > 1
                     end
                 end
             end
@@ -3168,7 +3178,13 @@ local function t_run_multiple(start,stop,font,attr,steps,nofsteps)
                             -- if we need more than ligatures we can outline the code and use functions
                             local s = getnext(start)
                             local l = nil
+                            local d = 0
                             while s do
+                                if s == stop then
+                                    d = 1
+                                elseif d > 0 then
+                                    d = d + 1
+                                end
                                 local lg = lookupmatch[getchar(s)]
                                 if lg then
                                     l = lg
@@ -3178,7 +3194,7 @@ local function t_run_multiple(start,stop,font,attr,steps,nofsteps)
                                 end
                             end
                             if l and l.ligature then
-                                return true
+                                return true, d > 1
                             end
                         end
                     else