From ae7c4eeb888ec22e71e4226ccc00acce966b14a5 Mon Sep 17 00:00:00 2001
From: Alban Linard <alban@linard.fr>
Date: Thu, 28 Jan 2016 11:14:48 +0100
Subject: [PATCH] Fix #2.

---
 src/formalisms/alphabet.lua                   | 16 ++--
 src/formalisms/automaton.lua                  | 46 +++++------
 src/formalisms/collection.lua                 | 10 +--
 src/formalisms/directed_hyper_multi_graph.lua |  8 +-
 src/formalisms/hyper_graph.lua                |  6 +-
 src/formalisms/hyper_multi_graph.lua          | 48 ++++++------
 src/formalisms/interrupt_timed_automaton.lua  | 78 +++++++++----------
 .../labelled_edges_hyper_multi_graph.lua      |  6 +-
 .../labelled_vertices_hyper_multi_graph.lua   |  6 +-
 src/formalisms/multi_graph.lua                |  6 +-
 src/formalisms/polynomial.lua                 | 38 ++++-----
 src/formalisms/record.lua                     |  8 +-
 test/formalisms/test_alphabet.lua             |  4 +-
 test/formalisms/test_automaton.lua            |  4 +-
 .../test_directed_hyper_multi_graph.lua       |  4 +-
 test/formalisms/test_hyper_multi_graph.lua    |  4 +-
 .../test_interrupt_timed_automaton.lua        |  4 +-
 .../test_labelled_edges_hyper_multi_graph.lua |  4 +-
 ...st_labelled_vertices_hyper_multi_graph.lua |  4 +-
 test/formalisms/test_polynomial.lua           |  4 +-
 20 files changed, 154 insertions(+), 154 deletions(-)

diff --git a/src/formalisms/alphabet.lua b/src/formalisms/alphabet.lua
index 0b6dfad..ac73570 100644
--- a/src/formalisms/alphabet.lua
+++ b/src/formalisms/alphabet.lua
@@ -12,22 +12,22 @@ local _      = Layer.reference "alphabet"
 --
 -- An alphabet is a set of symbols.
 
-layer.__labels__ = { alphabet = true }
+layer[Layer.key.labels] = { alphabet = true }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   symbol_type = {},
 }
 
 layer.symbols = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.symbol_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].symbol_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.symbol_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].symbol_type,
     },
   }
 }
diff --git a/src/formalisms/automaton.lua b/src/formalisms/automaton.lua
index 199703a..51ab0d9 100644
--- a/src/formalisms/automaton.lua
+++ b/src/formalisms/automaton.lua
@@ -28,7 +28,7 @@ local _      = Layer.reference "automaton"
 --
 -- For more information of automaton see [here](http://www.cs.odu.edu/~toida/nerzic/390teched/regular/fa/nfa-definitions.html)
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   labelled_edges_hyper_multi_graph,
   labelled_vertices_hyper_multi_graph,
   directed_hyper_multi_graph,
@@ -36,20 +36,20 @@ layer.__refines__ = {
   alphabet,
 }
 
-layer.__labels__ = { automaton = true }
+layer[Layer.key.labels] = { automaton = true }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   edge_type = {
     __tags__ = {
       letter = {
-        __value_type__      = _.__meta__.symbol_type,
+        __value_type__      = _ [Layer.key.meta].symbol_type,
         __value_container__ = _.symbols,
       },
     },
   },
   
   vertex_type  = {
-    __meta__ = {
+    [Layer.key.meta] = {
       __tags__ = {
         id = {},
       },
@@ -57,13 +57,13 @@ layer.__meta__ = {
   },
 
   initial_state_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record,
     },
-    __meta__ = {
+    [Layer.key.meta] = {
       tags = {
         vertex = {
-          __value_type__ = _.__meta__.vertex_type,
+          __value_type__ = _ [Layer.key.meta].vertex_type,
           __value_container__ = _.vertices,
         },
       },
@@ -71,13 +71,13 @@ layer.__meta__ = {
   },
 
   accept_state_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record,
     },
-    __meta__ = {
+    [Layer.key.meta] = {
       tags = {
         vertex = {
-          __value_type__ = _.__meta__.vertex_type,
+          __value_type__ = _ [Layer.key.meta].vertex_type,
           __value_container__ = _.vertices,
         },
       },
@@ -86,29 +86,29 @@ layer.__meta__ = {
 }
 
 layer.initials_states = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.initial_state_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].initial_state_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.initial_state_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].initial_state_type,
     },
   },
 }
 
 layer.accept_states = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.accept_state_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].accept_state_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.accept_state_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].accept_state_type,
     },
   },
 }
diff --git a/src/formalisms/collection.lua b/src/formalisms/collection.lua
index 9c5ee0e..ce33047 100644
--- a/src/formalisms/collection.lua
+++ b/src/formalisms/collection.lua
@@ -14,17 +14,17 @@ local layer = Layer.new {
 -- * `value_type`      : type of values
 -- * `value_container` : all values must reference an element of this container
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   key_type        = nil,
   key_container   = nil,
   value_type      = nil,
   value_container = nil,
 }
 
-layer.__checks__ = {
+layer[Layer.key.checks] = {
   check_collection = function (proxy)
     
-    local meta = proxy.__meta__
+    local meta = proxy[Layer.key.meta]
     do
       local exist = false 
       for _ in Layer.pairs(meta) do 
@@ -62,7 +62,7 @@ layer.__checks__ = {
             message = message .. tostring(key) .. " value : incompatible types. Waiting " .. tostring(meta["value_type"]) .. ", found " .. type(value) .. ". "
           else
             local exist = false
-            for _, ref in Layer.ipairs(value.__refines__) do
+            for _, ref in Layer.ipairs(value[Layer.key.refines]) do
               print(ref)
               if ref == meta["value_type"] then 
                 exist = true
@@ -101,7 +101,7 @@ layer.__checks__ = {
             message = message .. "key " .. tostring(key) .. " : incompatible types. Waiting " .. tostring(meta["key_type"]) .. ", found " .. type(key) .. ". "
           else
             local exist = false
-            for _, ref in Layer.ipairs(key.__refines__) do
+            for _, ref in Layer.ipairs(key[Layer.key.refines]) do
               if ref == meta["key_type"] then 
                 exist = true
                 break
diff --git a/src/formalisms/directed_hyper_multi_graph.lua b/src/formalisms/directed_hyper_multi_graph.lua
index 7bdba2d..a5c934e 100644
--- a/src/formalisms/directed_hyper_multi_graph.lua
+++ b/src/formalisms/directed_hyper_multi_graph.lua
@@ -11,15 +11,15 @@ local layer             = Layer.new {
 --
 -- A definition of Directed Hyper Graph is given [here](http://link.springer.com/chapter/10.1007/3-540-45446-2_20)
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph
 }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   edge_type = {
-    __meta__ = {
+    [Layer.key.meta] = {
       arrow_type = {
-        __meta__ = {
+        [Layer.key.meta] = {
           __tags__ = {
             input = {
               __value_type__ = "boolean",
diff --git a/src/formalisms/hyper_graph.lua b/src/formalisms/hyper_graph.lua
index b65a63e..f1acde7 100644
--- a/src/formalisms/hyper_graph.lua
+++ b/src/formalisms/hyper_graph.lua
@@ -15,13 +15,13 @@ local layer             = Layer.new {
 --
 -- For more information see [here](https://en.wikipedia.org/wiki/Hypergraph)
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph
 }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   edges = {
-    __checks__ = {
+    [Layer.key.checks] = {
       function ()
         -- TODO
         -- check identical edges
diff --git a/src/formalisms/hyper_multi_graph.lua b/src/formalisms/hyper_multi_graph.lua
index 34ecd07..1085749 100644
--- a/src/formalisms/hyper_multi_graph.lua
+++ b/src/formalisms/hyper_multi_graph.lua
@@ -15,22 +15,22 @@ local _          = Layer.reference "HMGT"
 --
 -- For more information of Hyper and Multi Graph, see [here](https://en.wikipedia.org/?title=Hypergraph)
 
-layer.__labels__ = { HMGT = true }
+layer[Layer.key.labels] = { HMGT = true }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   vertex_type = {},
 
   edge_type = {
-    __meta__ = {
+    [Layer.key.meta] = {
       arrow_type = {
-        __refines__ = {
+        [Layer.key.refines] = {
           record,
         },
 
-        __meta__ = {
+        [Layer.key.meta] = {
           tags = {
             vertex = {
-              value_type      = _.__meta__.vertex_type,
+              value_type      = _ [Layer.key.meta].vertex_type,
               value_container = _.vertices,
             },
           },
@@ -38,15 +38,15 @@ layer.__meta__ = {
       },
     },
     arrows = {
-      __refines__ = {
+      [Layer.key.refines] = {
         collection,
       },
-      __meta__ = {
-        value_type = _.__meta__.edge_type.__meta__.arrow_type,
+      [Layer.key.meta] = {
+        value_type = _ [Layer.key.meta].edge_type[Layer.key.meta].arrow_type,
       },
-      __default__ = {
-        __refines__ = {
-          _.__meta__.edge_type.__meta__.arrow_type,
+      [Layer.key.default] = {
+        [Layer.key.refines] = {
+          _ [Layer.key.meta].edge_type[Layer.key.meta].arrow_type,
         },
       },
     },
@@ -54,29 +54,29 @@ layer.__meta__ = {
 }
 
 layer.vertices = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    value_type = _.__meta__.vertex_type,
+  [Layer.key.meta] = {
+    value_type = _ [Layer.key.meta].vertex_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.vertex_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].vertex_type,
     },
   },
 }
 
 layer.edges = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    value_type = _.__meta__.edge_type,
+  [Layer.key.meta] = {
+    value_type = _ [Layer.key.meta].edge_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.edge_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].edge_type,
     }
   },
 }
diff --git a/src/formalisms/interrupt_timed_automaton.lua b/src/formalisms/interrupt_timed_automaton.lua
index 79d5887..4b71e16 100644
--- a/src/formalisms/interrupt_timed_automaton.lua
+++ b/src/formalisms/interrupt_timed_automaton.lua
@@ -28,21 +28,21 @@ local root       = Layer.reference (false)
 --For more information of Interrupt timed automaton see [here](http://arxiv.org/abs/1504.04541)
 
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   automaton,
 }
 
-layer.__labels__ = { ITA = true }
+layer[Layer.key.labels] = { ITA = true }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   analog_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record,
     },
-    __meta__ = {
+    [Layer.key.meta] = {
       __tags__ = {
         active_level = {
-          __value_type__      = _.__meta__.level_type,
+          __value_type__      = _ [Layer.key.meta].level_type,
           __value_container__ = _.levels,
         },
       },
@@ -52,10 +52,10 @@ layer.__meta__ = {
   level_type = {},
 
   guard_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record,
     },
-    __meta__ = {
+    [Layer.key.meta] = {
       __tags__ = {
         comparison = {
           __value_type__      = "string",
@@ -64,50 +64,50 @@ layer.__meta__ = {
       },
     },
     polynomial = {
-      __refines__ = {
+      [Layer.key.refines] = {
         collection,
       },
-      __meta__    = {
-        __value_type__ = _.__meta__.polynomial_type,
+      [Layer.key.meta]    = {
+        __value_type__ = _ [Layer.key.meta].polynomial_type,
       },
-      __default__ = {
-        __refines__ = {
-          _.__meta__.polynomial_type,
+      [Layer.key.default] = {
+        [Layer.key.refines] = {
+          _ [Layer.key.meta].polynomial_type,
         },
       },
     },
   },
 
   update_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       collection,
     },
-    __meta__ = {
-      __value_type__    = _.__meta__.polynomial_type,
-      __key_type__      = _.__meta__.analog_type,
+    [Layer.key.meta] = {
+      __value_type__    = _ [Layer.key.meta].polynomial_type,
+      __key_type__      = _ [Layer.key.meta].analog_type,
       __key_container__ = _.analogs,
     },
   },
 
   edge_type = {
     update = {
-      __refines__ = {
-        _.__meta__.update_type,
+      [Layer.key.refines] = {
+        _ [Layer.key.meta].update_type,
       },
     },
 
     guard = {
-      __refines__ = {
-        _.__meta__.guard_type
+      [Layer.key.refines] = {
+        _ [Layer.key.meta].guard_type
       },
     },
   },
 
   vertex_type  = {
-    __meta__ = {
+    [Layer.key.meta] = {
       __tags__ = {
         level = {
-          __value_type__      = _.__meta__.level_type,
+          __value_type__      = _ [Layer.key.meta].level_type,
           __value_container__ = _.levels,
         },
       },
@@ -116,13 +116,13 @@ layer.__meta__ = {
 
   initial_state_type = {
     analogs_init = {
-      __refines__ = {
+      [Layer.key.refines] = {
         collection,
       },
 
-      __meta__ = {
+      [Layer.key.meta] = {
         __value_type__    = "number",
-        __key_type__      = _.__meta__.analog_type,
+        __key_type__      = _ [Layer.key.meta].analog_type,
         __key_container__ = _.analogs,
       },
     },
@@ -130,29 +130,29 @@ layer.__meta__ = {
 }
 
 layer.analogs = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.analog_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].analog_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.analog_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].analog_type,
     },
   },
 }
 
 layer.levels = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.level_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].level_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.level_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].level_type,
     },
   },
 }
diff --git a/src/formalisms/labelled_edges_hyper_multi_graph.lua b/src/formalisms/labelled_edges_hyper_multi_graph.lua
index 551994f..48cb1c0 100644
--- a/src/formalisms/labelled_edges_hyper_multi_graph.lua
+++ b/src/formalisms/labelled_edges_hyper_multi_graph.lua
@@ -12,13 +12,13 @@ local layer             = Layer.new {
 --
 -- We only add in this formalism labels on edges.
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph
 }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   edge_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record
     },
   },
diff --git a/src/formalisms/labelled_vertices_hyper_multi_graph.lua b/src/formalisms/labelled_vertices_hyper_multi_graph.lua
index 07a838f..e06f87d 100644
--- a/src/formalisms/labelled_vertices_hyper_multi_graph.lua
+++ b/src/formalisms/labelled_vertices_hyper_multi_graph.lua
@@ -12,13 +12,13 @@ local layer             = Layer.new {
 --
 -- We only add in this formalism labels on vertices.
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph
 }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   vertex_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record,
     },
   },
diff --git a/src/formalisms/multi_graph.lua b/src/formalisms/multi_graph.lua
index 9f2374f..5e15a92 100644
--- a/src/formalisms/multi_graph.lua
+++ b/src/formalisms/multi_graph.lua
@@ -17,14 +17,14 @@ local layer             = Layer.new {
 --
 -- For more information see [here](https://en.wikipedia.org/wiki/Multigraph)
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph
 }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   edge_type = {
     arrows = {
-      __checks__ = {
+      [Layer.key.checks] = {
         function ()
           -- TODO
           -- check arity (size of arrows must equals 2)
diff --git a/src/formalisms/polynomial.lua b/src/formalisms/polynomial.lua
index 43b8a59..9d0a0f7 100644
--- a/src/formalisms/polynomial.lua
+++ b/src/formalisms/polynomial.lua
@@ -6,27 +6,27 @@ local layer      = Layer.new {
 }
 local _          = Layer.reference "polynomial"
 
-layer.__labels__ = { polynomial = true }
+layer[Layer.key.labels] = { polynomial = true }
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   variable_type = {},
 
   monomial_type = {
-    __refines__ = {
+    [Layer.key.refines] = {
       record
     },
-    __meta__ = {
+    [Layer.key.meta] = {
       __tags__ = {
         coefficient = {
           __value_type__ = "number",
         },
       },
       exponents = {
-        __refines__ = {
+        [Layer.key.refines] = {
           collection,
         },
-        __meta__ = {
-          __key_type__      = _.__meta__.variable_type,
+        [Layer.key.meta] = {
+          __key_type__      = _ [Layer.key.meta].variable_type,
           __key_container__ = _.variables,
           __value_type__    = "number",
         },
@@ -36,29 +36,29 @@ layer.__meta__ = {
 }
     
 layer.variables = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.variable_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].variable_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.variable_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].variable_type,
     },
   },
 }
     
 layer.monomials = {
-  __refines__ = {
+  [Layer.key.refines] = {
     collection,
   },
-  __meta__ = {
-    __value_type__ = _.__meta__.monomial_type,
+  [Layer.key.meta] = {
+    __value_type__ = _ [Layer.key.meta].monomial_type,
   },
-  __default__ = {
-    __refines__ = {
-      _.__meta__.monomial_type,
+  [Layer.key.default] = {
+    [Layer.key.refines] = {
+      _ [Layer.key.meta].monomial_type,
     },
   },
 }
diff --git a/src/formalisms/record.lua b/src/formalisms/record.lua
index 4dccba8..2d52c91 100644
--- a/src/formalisms/record.lua
+++ b/src/formalisms/record.lua
@@ -9,7 +9,7 @@ local layer = Layer.new {
 -- a record is a table where some keys are obligated.
 -- To do that we introduce the special key `tags`.
 
-layer.__meta__ = {
+layer[Layer.key.meta] = {
   tags = {
     -- If you want a key `name` in your record you wrote this :
     --  name = {
@@ -20,10 +20,10 @@ layer.__meta__ = {
   },
 }
     
-layer.__checks__ = {
+layer[Layer.key.checks] = {
   check_tags = function (proxy)
     local message = ""
-    local tags = proxy.__meta__.tags
+    local tags = proxy[Layer.key.meta].tags
     for tag, value in Layer.pairs(tags) do
       if value["value_type"] ~= nil or value["value_container"] ~= nil then
         if proxy[tag] == nil then
@@ -53,7 +53,7 @@ layer.__checks__ = {
               message = message .. tostring(tag) .. " value : incompatible types. Waiting " .. tostring(value["value_type"]) .. ", found " .. type(proxy[tag]) .. ". "
             else
               local exist = false
-              for _, ref in Layer.ipairs(proxy[tag].__refines__) do
+              for _, ref in Layer.ipairs(proxy[tag][Layer.key.refines]) do
                 if ref == value["value_type"] then 
                   exist = true
                   break
diff --git a/test/formalisms/test_alphabet.lua b/test/formalisms/test_alphabet.lua
index c281984..6656cf5 100644
--- a/test/formalisms/test_alphabet.lua
+++ b/test/formalisms/test_alphabet.lua
@@ -13,8 +13,8 @@ layer.__depends__ = {
 layer.model = {
   __label__ = "alphabet_model",
 
-  __refines__ = {
-    root.__meta__.alphabet_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].alphabet_type,
   },
 
   symbols = {
diff --git a/test/formalisms/test_automaton.lua b/test/formalisms/test_automaton.lua
index d256e13..6275003 100644
--- a/test/formalisms/test_automaton.lua
+++ b/test/formalisms/test_automaton.lua
@@ -14,8 +14,8 @@ layer.__depends__ = {
 layer.model = {
   __label__ = "automaton_model",
 
-  __refines__ = {
-    root.__meta__.automaton_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].automaton_type,
   },
 
   symbols = {
diff --git a/test/formalisms/test_directed_hyper_multi_graph.lua b/test/formalisms/test_directed_hyper_multi_graph.lua
index 5c646e7..ab02643 100644
--- a/test/formalisms/test_directed_hyper_multi_graph.lua
+++ b/test/formalisms/test_directed_hyper_multi_graph.lua
@@ -11,8 +11,8 @@ layer.__depends__ = {
 }
 
 layer.model = {
-  __refines__ = {
-    root.__meta__.directed_hyper_multi_graph_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].directed_hyper_multi_graph_type,
   },
   __label__ = "DHMGT_model",
 
diff --git a/test/formalisms/test_hyper_multi_graph.lua b/test/formalisms/test_hyper_multi_graph.lua
index f0b1674..8c47fcb 100644
--- a/test/formalisms/test_hyper_multi_graph.lua
+++ b/test/formalisms/test_hyper_multi_graph.lua
@@ -5,11 +5,11 @@ local layer             = Layer.new {
 }
 local _                 = Layer.reference "HMGT_model"
 
-layer.__refines__ = {
+layer[Layer.key.refines] = {
   hyper_multi_graph,
 }
 
-layer.__labels__ = { HMGT_model = true }
+layer[Layer.key.labels] = { HMGT_model = true }
 
 layer.vertices = {
   n1 = {},
diff --git a/test/formalisms/test_interrupt_timed_automaton.lua b/test/formalisms/test_interrupt_timed_automaton.lua
index d8202ad..73d4f3f 100644
--- a/test/formalisms/test_interrupt_timed_automaton.lua
+++ b/test/formalisms/test_interrupt_timed_automaton.lua
@@ -13,8 +13,8 @@ layer.__depends__ = {
 layer.model = {
   __label__ = "ITA_model",
 
-  __refines__ = {
-    root.__meta__.interrupt_timed_automaton_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].interrupt_timed_automaton_type,
   },
 
   symbols = {
diff --git a/test/formalisms/test_labelled_edges_hyper_multi_graph.lua b/test/formalisms/test_labelled_edges_hyper_multi_graph.lua
index ad7ae13..7f4374c 100644
--- a/test/formalisms/test_labelled_edges_hyper_multi_graph.lua
+++ b/test/formalisms/test_labelled_edges_hyper_multi_graph.lua
@@ -13,8 +13,8 @@ layer.__depends__ = {
 layer.model = {
   __label__ = "LEHMGT_model",
 
-  __refines__ = {
-    root.__meta__.labelled_edges_hyper_multi_graph_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].labelled_edges_hyper_multi_graph_type,
   },
 
   vertices = {
diff --git a/test/formalisms/test_labelled_vertices_hyper_multi_graph.lua b/test/formalisms/test_labelled_vertices_hyper_multi_graph.lua
index 1bc67c4..fca4233 100644
--- a/test/formalisms/test_labelled_vertices_hyper_multi_graph.lua
+++ b/test/formalisms/test_labelled_vertices_hyper_multi_graph.lua
@@ -13,8 +13,8 @@ layer.__depends__ = {
 layer.model = {
   __label__ = "LVHMGT_model",
 
-  __refines__ = {
-    root.__meta__.labelled_vertices_hyper_multi_graph_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].labelled_vertices_hyper_multi_graph_type,
   },
 
   vertices = {
diff --git a/test/formalisms/test_polynomial.lua b/test/formalisms/test_polynomial.lua
index d486bdd..7b3a581 100644
--- a/test/formalisms/test_polynomial.lua
+++ b/test/formalisms/test_polynomial.lua
@@ -13,8 +13,8 @@ layer.__depends__ = {
 layer.model = {
   __label__   = "polynomial_model",
 
-  __refines__ = {
-    root.__meta__.polynomial_type,
+  [Layer.key.refines] = {
+    root[Layer.key.meta].polynomial_type,
   },
 
   variables = {