[conf] move colorization to post_linebreak_filter

Addresses this behavior: http://tex.stackexchange.com/q/238539/14066

This is a breaking change but it hardly matters since font-based
colorization is deprecated and the old behavior can be restored by means
of a configuration setting.

1 files changed, 30 insertions, 2 deletions

diff --git a/src/luaotfload-configuration.lua b/src/luaotfload-configuration.lua
index 657d671..7791503 100644
--- a/src/luaotfload-configuration.lua
+++ b/src/luaotfload-configuration.lua
@@ -144,6 +144,23 @@ local registered_loaders = {
   tl2013     = "tl2013",
 }
 
+--[[doc--
+
+  The ``post_linebreak_filter`` has been made the default callback for
+  hooking the colorizer into. This helps with the linebreaking whose
+  inserted hyphens would remain unaffected by the coloring otherwise.
+
+  http://tex.stackexchange.com/q/238539/14066
+
+--doc]]--
+
+local permissible_color_callbacks = {
+  default               = "post_linebreak_filter",
+  pre_linebreak_filter  = "pre_linebreak_filter",
+  post_linebreak_filter = "post_linebreak_filter",
+  pre_output_filter     = "pre_output_filter",
+}
+
 
 -------------------------------------------------------------------------------
 ---                                DEFAULTS
@@ -479,9 +496,20 @@ local option_spec = {
     color_callback = {
       in_t      = string_t,
       out_t     = string_t,
-      transform = function (cb)
+      transform = function (cb_spec)
         --- These are the two that make sense.
-        return cb == "pre_output_filter" and cb or "pre_linebreak_filter"
+        local cb = permissible_color_callbacks[cb_spec]
+        if cb then
+          logreport ("log", 3, "conf",
+                     "Using callback \"%s\" for font colorization.",
+                     cb)
+          return cb
+        end
+        logreport ("log", 0, "conf",
+                    "Requested callback identifier \"%s\" invalid, "
+                    .. "falling back to default.",
+                    cb_spec)
+        return permissible_color_callbacks.default
       end,
     },
   },