provide hook for custom font resolver

2 files changed, 17 insertions, 4 deletions

diff --git a/luaotfload-features.lua b/luaotfload-features.lua
index cbdc36b..c405ae5 100644
--- a/luaotfload-features.lua
+++ b/luaotfload-features.lua
@@ -1003,9 +1003,11 @@ local prefixed          = P"name:" * ws * Cg(fontname, "name")
 --- with paths already, so we’ll add a less strict rule here.  anyways,
 --- we’ll emit a warning.
                         + P"file:" * ws * Cg(unsupported, "path")
-                        + P"file:" * ws * Cg(fontname,    "file")
+                        + P"file:" * ws * Cg(fontname, "file")
 --- EXPERIMENTAL: kpse lookup
-                        + P"kpse:" * ws * Cg(fontname,    "kpse")
+                        + P"kpse:" * ws * Cg(fontname, "kpse")
+--- EXPERIMENTAL: custom lookup
+                        + P"my:" * ws * Cg(fontname, "my")
 local unprefixed        = Cg(fontname, "anon")
 local path_lookup       = lbrk * Cg(C((1-rbrk)^1), "path") * rbrk
 
@@ -1071,7 +1073,7 @@ local import_values = {
     { "mode",   true },
 }
 
-local lookup_types = { "anon", "file", "kpse", "name", "path" }
+local lookup_types = { "anon", "file", "kpse", "my", "name", "path" }
 
 local select_lookup = function (request)
     for i=1, #lookup_types do
diff --git a/luaotfload.dtx b/luaotfload.dtx
index 83885a0..7beca09 100644
--- a/luaotfload.dtx
+++ b/luaotfload.dtx
@@ -1917,7 +1917,7 @@ request_resolvers.path = function (specification)
 end
 
 %    \end{macrocode}
-% {\bfseries EXPERIMENTAL}
+% {\bfseries EXPERIMENTAL}:
 % \identifier{kpse}-only resolver, for those who can do without system
 % fonts.
 %
@@ -1944,6 +1944,17 @@ request_resolvers.kpse = function (specification)
 end
 
 %    \end{macrocode}
+% Also {\bfseries EXPERIMENTAL}:
+% custom file resolvers via callback.
+%
+%    \begin{macrocode}
+create_callback("luaotfload.resolve_font", "simple", dummy_function)
+
+request_resolvers.my = function (specification)
+    call_callback("luaotfload.resolve_font", specification)
+end
+
+%    \end{macrocode}
 % We create a callback for patching fonts on the fly, to be used by other
 % packages.
 % It initially contains the empty function that we are going to override