util.multitable: Add :iter() method to iterate over results at a fixed depth (paramet...

diff --git a/util/multitable.lua b/util/multitable.lua
index 66b9bd8aba1a90481d80efcaa056773552a61f60..388f60f33a5c1330f03b470eae2afeb434e8ed5d 100644 (file)
--- a/util/multitable.lua
+++ b/util/multitable.lua
@@ -6,12 +6,9 @@
 -- COPYING file in the source package for more information.
 --
 
-
-
 local select = select;
-local t_insert = table.insert;
-local pairs = pairs;
-local next = next;
+local t_insert, t_remove = table.insert, table.remove;
+local unpack, pairs, next, type = unpack, pairs, next, type;
 
 module "multitable"
 
@@ -129,6 +126,41 @@ local function search_add(self, results, ...)
        return results;
 end
 
+function iter(self, ...)
+       local query = { ... };
+       local maxdepth = select("#", ...);
+       local stack = { self.data };
+       local keys = { };
+       local function it(self)
+               local depth = #stack;
+               local key = next(stack[depth], keys[depth]);
+               if key == nil then -- Go up the stack
+                       t_remove(stack);
+                       t_remove(keys);
+                       if depth > 1 then
+                               return it(self);
+                       end
+                       return; -- The end
+               else
+                       keys[depth] = key;
+               end
+               local value = stack[depth][key];
+               if depth == maxdepth then -- Result
+                       local result = {}; -- Collect keys forming path to result
+                       for i = 1, depth do
+                               result[i] = keys[i];
+                       end
+                       return unpack(result, 1, depth);
+               else
+                       if (query[depth] == nil or key == query[depth]) and type(value) == "table" then -- Descend
+                               t_insert(stack, value);
+                       end
+                       return it(self);
+               end
+       end;
+       return it, self;
+end
+
 function new()
        return {
                data = {};
@@ -138,6 +170,7 @@ function new()
                remove = remove;
                search = search;
                search_add = search_add;
+               iter = iter;
        };
 end