diff --git a/examples/.idea/modules.xml b/examples/.idea/modules.xml
index 4b3b58ae48d..cf95d722bf2 100644
--- a/examples/.idea/modules.xml
+++ b/examples/.idea/modules.xml
@@ -3,6 +3,7 @@
   <component name="ProjectModuleManager">
     <modules>
       <module fileurl="file://$PROJECT_DIR$/examples.iml" filepath="$PROJECT_DIR$/examples.iml" />
+      <module fileurl="file://$PROJECT_DIR$/../grammar/grammar.iml" filepath="$PROJECT_DIR$/../grammar/grammar.iml" />
     </modules>
   </component>
 </project>
diff --git a/examples/src/collections/IIterator.jetl b/examples/src/collections/IIterator.jetl
index 31469b269b3..2ec8bc66cae 100644
--- a/examples/src/collections/IIterator.jetl
+++ b/examples/src/collections/IIterator.jetl
@@ -2,16 +2,16 @@ interface class IIterator<out T> {
   fun next() : T
   val hasNext : Boolean
 
-  fun toArray(buffer : WriteOnlyArray<T>) : Int { // T is still an in-parameter
+  fun toArray(buffer : MutableArray<in T>) : Int { // T is still an in-parameter
     return fillBuffer(buffer, 0, buffer.size)
   }
 
-  fun toArray(buffer : WriteOnlyArray<T>, from : Int, length : Int) : Int { // T is still an in-parameter
+  fun toArray(buffer : MutableArray<in T>, from : Int, length : Int) : Int { // T is still an in-parameter
     if (from < 0 || from > buffer.lastIndex || length < 0 || length > buffer.size - from) {
       throw IndexOutOfBoundsException();
     }
 
-    if (len == 0) return 0;
+    if (len == 0) return 0
 
     var count = 0;
     for (i in [from .. from + length - 1]) {
diff --git a/grammar/grammar.iml b/grammar/grammar.iml
new file mode 100644
index 00000000000..d5c07432750
--- /dev/null
+++ b/grammar/grammar.iml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
+
diff --git a/grammar/src/class.grm b/grammar/src/class.grm
new file mode 100644
index 00000000000..cde2a46c394
--- /dev/null
+++ b/grammar/src/class.grm
@@ -0,0 +1,50 @@
+/*
+
+internal class Example<X, T : Comparable<X>>(protected val x : Foo<X, T>, y : Some)
+    : Bar(x), Foo<X, T> by x, IAbstractSome by y.asAbstract()
+    where
+      T : Function<Object, Object>
+{
+  // members
+}
+
+*/
+
+class
+  : classModifier* "class" SimpleName
+      ("<" typeParameter{","} ">")?
+      ("(" defaultConstructorParameter{","} ")")?
+      (":" delegationSpecifier{","})?
+      ("where" typeConstraint{","})?  // Syntax is questionable
+      ("{" memberDeclaration{","} "}"?
+  ;
+
+classModifier
+  : accessModifier
+  : "abstract"
+  : "sealed"
+  ;
+
+delegationSpecifier
+  : constructorInvocation // type and constructor arguments
+  : explicitDelegation
+  ;
+
+explicitDelegation
+  : userType "by" expression // Syntax is questionable
+  ;
+
+typeParameter
+  : varianceAnnotation? SimpleName (":" userType)?
+  ;
+
+typeConstraint
+  : userType ":" userType
+  // other constraints, maybe
+  ;
+
+defaultConstructorParameter
+  : accessModifier? ("val" | "var")? parameter
+  ;
+
+
diff --git a/grammar/src/class_members.grm b/grammar/src/class_members.grm
new file mode 100644
index 00000000000..d78cdfdc423
--- /dev/null
+++ b/grammar/src/class_members.grm
@@ -0,0 +1,82 @@
+class Example(a : Foo, i : Int) : Bar(i), Some {
+  // constrtuctors:
+  public this(a : Foo) : this(a, 0)
+
+  public this(a : Foo) : Bar(5), Some(a) {
+    // code
+  }
+
+  // functions
+  abstract fun foo(a : Bar)
+
+  fun foo(a : Bar) = 0
+
+  fun foo(a : Bar) = {
+    return 0
+  }
+
+  fun foo(a : Bar) { // return type is Unit
+
+  // properties
+  val x : Int = 5
+  var y : Double = 7.0d
+  var z : String = "SDfsdf" {
+    get() = $z + "sdfsd"
+    private set(s : String) { $z = s } // TODO: allow to omit the type here?
+  }
+}
+
+
+// h5. Grammar
+
+memberDeclaration
+  : constructor
+  : method
+  : property
+  : class //TODO : static
+//  : constant ???
+  ;
+
+constructor
+  : accessModifier? "this" functionParameters (":" initializers) block
+  ;
+
+initializers
+  : "this" functionArguments
+  : constructorInvocation // type parameters may (must?) be omitted
+  ;
+
+super
+  : "super" "<" name ">"
+  ;
+
+method
+  : methodModifier* "fun" SimpleName functionParameters (":" type)? functionBody?
+  ;
+
+functionParameters
+  : "(" (parameter{","})? ")"
+  ;
+
+block
+  : "{" statements "}"
+  ;
+
+functionBody
+  : block
+  : "=" expression
+  ;
+
+property
+  : propertyModifier* ("val" | "var") SimpleName (":" type)? ("=" expression)?
+    "{" getter? setter? "}"
+  ;
+
+getter
+  : methodModifier* "get" "(" ")" functionBody
+  ;
+
+setter
+  : methodModifier* "set" "(" parameter ")" functionBody
+  ;
+
diff --git a/grammar/src/expressions.grm b/grammar/src/expressions.grm
new file mode 100644
index 00000000000..d769b947b02
--- /dev/null
+++ b/grammar/src/expressions.grm
@@ -0,0 +1,34 @@
+expression
+  : "new" constructorInvocation
+  : literalConstant
+  : functionLiteral
+  : tupleLiteral
+  : "null"
+  : binOpExpression
+  : unOpExpression
+  : name functionParameters? // ambiguity here
+  : FieldName
+  : if
+// list comprehension
+  : jump
+  ;
+
+jump
+  : "throw" expression
+  : "return" expression
+  : "continue" SimpleName
+  : "break" SimpleName
+// yield ?
+  ;
+
+tupleLiteral
+  : "(" expression{","} ")"
+  ;
+
+functionLiteral
+  : "{" (parameter | SimpleName)* "=>" expression "}"
+  ;
+
+constructorInvocation
+  : userType "(" expression{","} ")"
+  ;
diff --git a/grammar/src/lexical.grm b/grammar/src/lexical.grm
new file mode 100644
index 00000000000..26e8e971526
--- /dev/null
+++ b/grammar/src/lexical.grm
@@ -0,0 +1,5 @@
+
+
+SimpleName : /*java identifier*/;
+FieldName : "$" SimpleName;
+name : /*possibly qualified name*/;
diff --git a/grammar/src/other.grm b/grammar/src/other.grm
new file mode 100644
index 00000000000..bc4806ee703
--- /dev/null
+++ b/grammar/src/other.grm
@@ -0,0 +1,15 @@
+accessModifier
+  : "private"
+  : "protected"
+  : "public"
+  : "internal"
+  ;
+
+parameter
+  : SimpleName ":" type
+  // TODO: lazy, out, ref ...
+  ;
+
+functionArguments
+  : "(" (expression{","})* ")"
+  ;
diff --git a/grammar/src/types.grm b/grammar/src/types.grm
new file mode 100644
index 00000000000..cd01d0768e5
--- /dev/null
+++ b/grammar/src/types.grm
@@ -0,0 +1,29 @@
+/*
+
+Foo<Bar<X>, T, Object> // user type
+{A, Object => Foo} // function type
+{ => Foo} // function with no arguments
+(A, B, C) // tuple type
+() // 0-ary tuple type (Unit)
+
+*/
+
+type
+  : userType
+  : functionType
+  : tupleType
+  ;
+
+userType
+  : name ("<" type{","} ">")?
+  ;
+
+functionType
+  : "{" type{","} "=>" type "}"
+  ;
+
+tupleType
+  : "(" type"{","} ")"
+  ;
+
+