Added idea on dependencies

TODO.md

@@ -8,6 +8,10 @@
 
 *   TC dependency issues
 
+    *   [ideas/dependency.md][1]
+
+  [1]: ideas/dependency.md
+
 
 ### Data model ###
 

ideas/dependency.md

@@ -0,0 +1,54 @@
+Notes: example to show idea of dependency markup
+
+
+# Demo: Dependency markup #
+
+This is for demonstration of way of showing dependency.
+
+The idea is to use dependency points.  The dependency point (DP) is a special
+TC that is identified by `{ID}`, where ID conforms to a unix path.
+
+*   the divider is `/`
+
+*   one special case is root DP, which has has name `/`
+
+*   you can call DP by something like `{/env2/}`. Scope of this declaration
+    is downwards, until next one or end
+
+
+## {/} prepare env=0 ##
+ 1. `x = 1`
+ 2. `y = 2`
+ 3. `m =`
+
+## {/env2} prepare env called 1 ##
+ 1. prepare env0
+ 2. `m = one`
+
+## {/env2} prepare something two ##
+ 1. prepare env0
+ 2. `m = two`
+
+{/env1/}
+
+## case 1.1 ##
+ 1. prepare env1
+ 2. do thing 1.1.1
+ 3. do thing 1.1.2
+
+## case 1.2 ##
+ 2. do thing 1.2.1
+ 3. do thing 1.2.2
+
+{/env2/}
+
+## case 2.1 ##
+ 1. prepare env2
+ 2. do thing 2.1.2
+ 3. do thing 2.1.2
+
+## case 2.2 ##
+ 1. prepare env2
+ 2. do thing 2.2.1
+ 3. do thing 2.2.2
+