diff --git a/docs/development/including_modules.md b/docs/development/including_modules.md
new file mode 100644
index 0000000..f201a0b
--- /dev/null
+++ b/docs/development/including_modules.md
@@ -0,0 +1,60 @@
+# Modules inclusion
+
+Module is, at the low level, a statement that modifies a given context by adding
+here local and exported symbols, performing some tasks and even returning some value
+we don't need for now.
+
+The compiled module is therefore a statement. When we execute it on some context,
+it wills it with all it symbols, private too.
+
+If we call it on another context, it will do it once more, no caching. This is unnecessary
+if not dangerous repetition.
+
+## What is inclusion?
+
+The _goal_ of the inclusion is to make _exported symbols_ available in a given context,
+without re-executing included module initialization code. So, when we hit the `import foo`,
+we should check that foo module was executed, execute it if not on special context we store in the library, then copy all public symbols from fooContext into current one.
+
+## Class pseudo-module
+
+Mostly same we can do with a class
+
+## Module initialization
+
+We can just put the code into the module code:
+
+    module lying.samples.module
+    // or package?
+    
+    val startuptTime = Instant.now()
+
+    // private: not available from outside
+    private fun moduleInitialization() {
+        // long code
+    }
+
+    // this will be called only once
+    moduleInitialization()
+
+## class initialization
+
+    class foo {
+        
+        private static var instanceCounter = 0
+        
+        val instanceId = instanceCounter
+        
+        fun close() {
+            instanceCounter--
+        }
+
+        // instance initializatino could be as this:
+        if( instanceId > 100 )
+            throw Exception("Too many instances")
+
+        static {
+            // static, one-per-class initializer could be posted here
+            instanceCounter = 1
+        }
+    }
diff --git a/library/src/commonMain/kotlin/net/sergeych/lyng/SymbolSpace.kt b/library/src/commonMain/kotlin/net/sergeych/lyng/SymbolSpace.kt
new file mode 100644
index 0000000..9ff22f6
--- /dev/null
+++ b/library/src/commonMain/kotlin/net/sergeych/lyng/SymbolSpace.kt
@@ -0,0 +1,13 @@
+package net.sergeych.lyng
+
+
+
+class Symbols(
+    unitType: UnitType,
+    val name: String,
+    val x: TypeDecl
+) {
+    enum class UnitType {
+        Module, Function, Lambda
+    }
+}
\ No newline at end of file
diff --git a/library/src/commonMain/kotlin/net/sergeych/lyng/TypeDecl.kt b/library/src/commonMain/kotlin/net/sergeych/lyng/TypeDecl.kt
index 35c890b..8fbed99 100644
--- a/library/src/commonMain/kotlin/net/sergeych/lyng/TypeDecl.kt
+++ b/library/src/commonMain/kotlin/net/sergeych/lyng/TypeDecl.kt
@@ -1,5 +1,21 @@
 package net.sergeych.lyng
 
 sealed class TypeDecl {
+    // ??
+    data class Fn(val argTypes: List<ArgsDeclaration.Item>, val retType: TypeDecl) : TypeDecl()
     object Obj : TypeDecl()
-}
\ No newline at end of file
+}
+
+/*
+To use in the compiler, we need symbol information when:
+
+- declaring a class: the only way to export its public/protected symbols is to know it in compiler time
+- importing a module: actually,  we cam try to do it in a more efficient way.
+
+Importing module:
+
+The moudule is efficiently a statement, that initializes it with all its symbols modifying some context.
+
+The thing is, we need only
+
+ */
\ No newline at end of file