1 files changed, 135 insertions, 0 deletions

diff --git a/src/FbTk/LResourceHelper.lua b/src/FbTk/LResourceHelper.lua
new file mode 100644
index 0000000..f336e05
--- /dev/null
+++ b/src/FbTk/LResourceHelper.lua
@@ -0,0 +1,135 @@
+read_resource, write_resource, res_magic = ...;
+
+local cat_magic = {};
+
+local function myerror(table, msg)
+    error(getmetatable(table)._fullname .. ': ' .. msg);
+end;
+
+local function check_arg(table, key)
+    if type(key) ~= 'string' then
+        myerror(table, 'expecting strings as keys.');
+    end;
+    if string.match(key, "^_") then
+        myerror(table, 'resource names must not begin with "_".');
+    end;
+    local t = getmetatable(table)[key];
+    return t, getmetatable(t);
+end;
+
+local new_cat;
+local function newindex(table, key, value)
+    local meta = getmetatable(table);
+    local t, mt = check_arg(table, key);
+
+    if type(value) == 'table' then
+        if mt == res_magic then
+            myerror(table, '"' .. key .. '" is a resource.');
+        end;
+        if mt == nil or mt._magic ~= cat_magic then
+            t = new_cat(table, key);
+        end;
+        for k,v in pairs(value) do
+            t[k] = v;
+        end;
+    else
+        if mt ~= nil and mt._magic == cat_magic and mt._state == 1 then
+            myerror(table, '"' .. key .. '" is a category.');
+        elseif mt == res_magic then
+            write_resource(t, value);
+        else
+            meta[key] = value;
+        end;
+    end;
+end;
+
+local function index(table, key)
+    local t, mt = check_arg(table, key);
+
+    if mt == res_magic then
+        return read_resource(t);
+    end;
+
+    return t;
+end;
+
+new_cat = function(table, key)
+    local meta = getmetatable(table);
+    local mt = {
+        __newindex = newindex, __index = index,
+        _magic = cat_magic, _fullname = meta._fullname .. '.' .. key, _state = 0
+    };
+    meta[key] = setmetatable({}, mt);
+    return meta[key];
+end;
+
+local function register_resource(root, name, object)
+    local meta = getmetatable(root);
+    meta._state = 1;
+
+    local head, tail = string.match(name, '^(%a+)%.?(.*)');
+    local t = meta[head];
+    if tail == '' then
+        meta[head] = object;
+        if getmetatable(object) == res_magic then
+            write_resource(object, t);
+        end;
+        return t;
+    end;
+
+    if t == nil then
+        t = new_cat(root, head);
+    end;
+    return register_resource(t, tail, object);
+end;
+
+local function dump_value(val)
+    if type(val) == "string" then
+        return string.format('%q', val);
+    elseif type(val) == "number" then
+        return string.format('%g', val);
+    else
+        error('Unsupported value type: ' .. type(val));
+    end;
+end;
+
+local function dump_(root, fd)
+    local meta = getmetatable(root);
+    if not string.match(meta._fullname, "^[%a.]+$") then
+        error("Someone has been messing with metatables.");
+    end;
+
+    for k, v in pairs(meta) do
+        if type(k) == "string" and string.match(k, "^%a+$") then
+            local mt = getmetatable(v);
+
+            fd:write(meta._fullname, '.', k, ' = ');
+            if mt ~= nil and mt._magic == cat_magic then
+                fd:write('{}\n');
+                dump(v);
+                fd:write('\n');
+            else
+                if mt == res_magic then
+                    v = read_resource(v);
+                end;
+                fd:write(dump_value(v), '\n');
+            end;
+        end;
+    end;
+end;
+
+local function dump(root, file)
+    local fd = io.open(file, 'w');
+    dump_(root, fd);
+    fd:close();
+end;
+
+local function make_root(name)
+    local t = {
+        __newindex = newindex, __index = index,
+        _magic = cat_magic, _fullname = name, _state = 0
+    };
+    getfenv()[name] = setmetatable({}, t);
+end;
+
+return make_root, register_resource, dump;