1 files changed, 165 insertions, 0 deletions
diff --git a/tex/context/base/l-lua.lua b/tex/context/base/l-lua.lua
index 7c78a4031..837f03d2a 100644
--- a/tex/context/base/l-lua.lua
+++ b/tex/context/base/l-lua.lua
@@ -147,3 +147,168 @@ function optionalrequire(...)
         return result
     end
 end
+
+-- Code moved from data-lua and changed into a plug-in.
+
+-- We overload the regular loader. We do so because we operate mostly in
+-- tds and use our own loader code. Alternatively we could use a more
+-- extensive definition of package.path and package.cpath but even then
+-- we're not done. Also, we now have better tracing.
+--
+-- -- local mylib = require("libtest")
+-- -- local mysql = require("luasql.mysql")
+
+local gsub, format = string.gsub, string.format
+
+local package    =  package
+local searchers  = package.searchers or package.loaders
+
+local libpaths   = nil
+local clibpaths  = nil
+local libhash    = { }
+local clibhash   = { }
+local libextras  = { }
+local clibextras = { }
+
+-- dummies
+
+local filejoin   = file and file.join        or function(path,name)   return path .. "/" .. name end
+local isreadable = file and file.is_readable or function(name)        local f = io.open(name) if f then f:close() return true end end
+local addsuffix  = file and file.addsuffix   or function(name,suffix) return name .. "." .. suffix end
+
+--
+
+local function cleanpath(path) -- hm, don't we have a helper for this?
+    return path
+end
+
+local helpers    = package.helpers or {
+    libpaths  = function() return { } end,
+    clibpaths = function() return { } end,
+    cleanpath = cleanpath,
+    trace     = false,
+    report    = function(...) print(format(...)) end,
+}
+package.helpers  = helpers
+
+local function getlibpaths()
+    return libpaths or helpers.libpaths(libhash)
+end
+
+local function getclibpaths()
+    return clibpaths or helpers.clibpaths(clibhash)
+end
+
+package.libpaths  = getlibpaths
+package.clibpaths = getclibpaths
+
+function package.extralibpath(...)
+    local libpaths  = getlibpaths()
+    local pathlist  = { ... }
+    local cleanpath = helpers.cleanpath
+    local trace     = helpers.trace
+    local report    = helpers.report
+    for p=1,#pathlist do
+        local paths = pathlist[p]
+        for i=1,#paths do
+            local path = cleanpath(paths[i])
+            if not libhash[path] then
+                if trace then
+                    libraries("! extra lua path '%s'",path)
+                end
+                libextras[#libextras+1] = path
+                libpaths [#libpaths +1] = path
+            end
+        end
+    end
+end
+
+function package.extraclibpath(...)
+    local clibpaths = getclibpaths()
+    local pathlist  = { ... }
+    local cleanpath = helpers.cleanpath
+    local trace     = helpers.trace
+    local report    = helpers.report
+    for p=1,#pathlist do
+        local paths = pathlist[p]
+        for i=1,#paths do
+            local path = cleanpath(paths[i])
+            if not clibhash[path] then
+                if trace then
+                    report("! extra lib path '%s'",path)
+                end
+                clibextras[#clibextras+1] = path
+                clibpaths [#clibpaths +1] = path
+            end
+        end
+    end
+end
+
+if not searchers[-2] then
+    -- use package-path and package-cpath
+    searchers[-2] = searchers[2]
+end
+
+searchers[2] = function(name)
+    return helpers.loaded(name)
+end
+
+local function loadedaslib(resolved,rawname)
+    return package.loadlib(resolved,"luaopen_" .. gsub(rawname,"%.","_"))
+end
+
+local function loadedbylua(name)
+    if helpers.trace then
+        helpers.report("! locating %q using normal loader",name)
+    end
+    return searchers[-2](name)
+end
+
+local function loadedbypath(name,rawname,paths,islib,what)
+    local trace  = helpers.trace
+    local report = helpers.report
+    if trace then
+        report("! locating %q as %q on %q paths",rawname,name,what)
+    end
+    for p=1,#paths do
+        local path = paths[p]
+        local resolved = filejoin(path,name)
+        if trace then -- mode detail
+            report("! checking for %q using %q path %q",name,what,path)
+        end
+        if isreadable(resolved) then
+            if trace then
+                report("! lib %q located on %q",name,resolved)
+            end
+            if islib then
+                return loadedaslib(resolved,rawname)
+            else
+                return loadfile(resolved)
+            end
+        end
+    end
+end
+
+local function notloaded(name)
+    if helpers.trace then
+        helpers.report("? unable to locate library %q",name)
+    end
+end
+
+helpers.loadedaslib  = loadedaslib
+helpers.loadedbylua  = loadedbylua
+helpers.loadedbypath = loadedbypath
+helpers.notloaded    = notloaded
+
+function helpers.loaded(name)
+    local thename   = gsub(name,"%.","/")
+    local luaname   = addsuffix(thename,"lua")
+    local libname   = addsuffix(thename,os.libsuffix)
+    local libpaths  = getlibpaths()
+    local clibpaths = getclibpaths()
+    return loadedbypath(luaname,name,libpaths,false,"lua")
+        or loadedbypath(luaname,name,clibpaths,false,"lua")
+        or loadedbypath(libname,name,clibpaths,true,"lib")
+        or loadedbylua(name)
+        or notloaded(name)
+end