diff --git a/Cargo.lock b/Cargo.lock
index f16dee5060..7966077cd3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -474,6 +474,13 @@ dependencies = [
  "rustpython-parser",
 ]
 
+[[package]]
+name = "nac3type"
+version = "0.1.0"
+dependencies = [
+ "rustpython-parser",
+]
+
 [[package]]
 name = "new_debug_unreachable"
 version = "1.0.4"
diff --git a/Cargo.toml b/Cargo.toml
index 938324ad75..a7cd60f8ef 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,4 +3,5 @@ members = [
   "nac3core",
   "nac3standalone",
   "nac3embedded",
+  "nac3type",
 ]
diff --git a/nac3type/Cargo.toml b/nac3type/Cargo.toml
new file mode 100644
index 0000000000..eb548c321e
--- /dev/null
+++ b/nac3type/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "nac3type"
+version = "0.1.0"
+authors = ["M-Labs"]
+edition = "2018"
+
+[dependencies]
+rustpython-parser = { git = "https://github.com/RustPython/RustPython", branch = "master" }
+
+
diff --git a/nac3type/src/lib.rs b/nac3type/src/lib.rs
new file mode 100644
index 0000000000..fed80085ec
--- /dev/null
+++ b/nac3type/src/lib.rs
@@ -0,0 +1,5 @@
+extern crate rustpython_parser;
+
+
+mod types;
+
diff --git a/nac3type/src/types.rs b/nac3type/src/types.rs
new file mode 100644
index 0000000000..35b21bb345
--- /dev/null
+++ b/nac3type/src/types.rs
@@ -0,0 +1,179 @@
+use std::collections::HashMap;
+
+#[derive(PartialEq, Eq, Copy, Clone)]
+pub struct PrimitiveId(usize);
+
+#[derive(PartialEq, Eq, Copy, Clone)]
+pub struct ClassId(usize);
+
+#[derive(PartialEq, Eq, Copy, Clone)]
+pub struct ParamId(usize);
+
+#[derive(PartialEq, Eq, Copy, Clone, Hash)]
+pub struct VariableId(usize);
+
+#[derive(PartialEq, Eq, Clone)]
+pub enum Type {
+    BotType,
+    SelfType,
+    PrimitiveType(PrimitiveId),
+    ClassType(ClassId),
+    VirtualClassType(ClassId),
+    ParametricType(ParamId, Vec<Type>),
+    TypeVariable(VariableId),
+}
+
+pub struct FnDef {
+    pub args: Vec<Type>,
+    pub result: Option<Type>,
+}
+
+pub struct TypeDef<'a> {
+    pub name: &'a str,
+    pub fields: HashMap<&'a str, Type>,
+    pub methods: HashMap<&'a str, FnDef>,
+}
+
+pub struct ClassDef<'a> {
+    pub base: TypeDef<'a>,
+    pub parents: Vec<ClassId>,
+}
+
+pub struct ParametricDef<'a> {
+    pub base: TypeDef<'a>,
+    pub params: Vec<VariableId>,
+}
+
+pub struct VarDef<'a> {
+    pub name: &'a str,
+    pub bound: Vec<Type>,
+}
+
+pub struct GlobalContext<'a> {
+    primitive_defs: Vec<TypeDef<'a>>,
+    class_defs: Vec<ClassDef<'a>>,
+    parametric_defs: Vec<ParametricDef<'a>>,
+    var_defs: Vec<VarDef<'a>>,
+    sym_table: HashMap<&'a str, Type>,
+}
+
+impl<'a> GlobalContext<'a> {
+    pub fn new(primitives: Vec<TypeDef<'a>>) -> GlobalContext {
+        let mut sym_table = HashMap::new();
+        for (i, t) in primitives.iter().enumerate() {
+            sym_table.insert(t.name, Type::PrimitiveType(PrimitiveId(i)));
+        }
+        return GlobalContext {
+            primitive_defs: primitives,
+            class_defs: Vec::new(),
+            parametric_defs: Vec::new(),
+            var_defs: Vec::new(),
+            sym_table,
+        };
+    }
+
+    pub fn add_class(&mut self, def: ClassDef<'a>) {
+        self.sym_table.insert(
+            def.base.name,
+            Type::ClassType(ClassId(self.class_defs.len())),
+        );
+        self.class_defs.push(def);
+    }
+    pub fn add_parametric(&mut self, def: ParametricDef<'a>) {
+        let params = def.params.iter().map(|&v| Type::TypeVariable(v)).collect();
+        self.sym_table.insert(
+            def.base.name,
+            Type::ParametricType(ParamId(self.parametric_defs.len()), params),
+        );
+        self.parametric_defs.push(def);
+    }
+
+    pub fn add_variable(&mut self, def: VarDef<'a>) {
+        self.sym_table.insert(
+            def.name,
+            Type::TypeVariable(VariableId(self.var_defs.len())),
+        );
+        self.var_defs.push(def);
+    }
+
+    pub fn add_variable_private(&mut self, def: VarDef<'a>) {
+        self.var_defs.push(def);
+    }
+
+    pub fn get_primitive_mut(&mut self, id: PrimitiveId) -> Option<&mut TypeDef<'a>> {
+        self.primitive_defs.get_mut(id.0)
+    }
+
+    pub fn get_primitive(&self, id: PrimitiveId) -> Option<&TypeDef> {
+        self.primitive_defs.get(id.0)
+    }
+
+    pub fn get_class_mut(&mut self, id: ClassId) -> Option<&mut ClassDef<'a>> {
+        self.class_defs.get_mut(id.0)
+    }
+
+    pub fn get_class(&self, id: ClassId) -> Option<&ClassDef> {
+        self.class_defs.get(id.0)
+    }
+
+    pub fn get_parametric_mut(&mut self, id: ParamId) -> Option<&mut ParametricDef<'a>> {
+        self.parametric_defs.get_mut(id.0)
+    }
+
+    pub fn get_parametric(&self, id: ParamId) -> Option<&ParametricDef> {
+        self.parametric_defs.get(id.0)
+    }
+
+    pub fn get_variable_mut(&mut self, id: VariableId) -> Option<&mut VarDef<'a>> {
+        self.var_defs.get_mut(id.0)
+    }
+
+    pub fn get_variable(&self, id: VariableId) -> Option<&VarDef> {
+        self.var_defs.get(id.0)
+    }
+
+    pub fn get_type(&self, name: &str) -> Option<Type> {
+        // TODO: change this to handle import
+        self.sym_table.get(name).map(|v| v.clone())
+    }
+}
+
+impl Type {
+    pub fn subst(&self, map: &Option<HashMap<VariableId, Type>>) -> Type {
+        if let Some(m) = map {
+            match self {
+                Type::TypeVariable(id) => m.get(id).unwrap_or(self).clone(),
+                Type::ParametricType(id, params) => {
+                    Type::ParametricType(*id, params.iter().map(|v| v.subst(map)).collect())
+                }
+                _ => self.clone(),
+            }
+        } else {
+            self.clone()
+        }
+    }
+
+    pub fn inv_subst(&self, map: &Vec<(Type, Type)>) -> Type {
+        for (from, to) in map.iter() {
+            if self == from {
+                return to.clone()
+            }
+        }
+        match self {
+            Type::ParametricType(id, params) => {
+                Type::ParametricType(*id, params.iter().map(|v| v.inv_subst(map)).collect())
+            },
+            _ => self.clone()
+        }
+    }
+
+    pub fn get_subst(&self, ctx: &GlobalContext) -> Option<HashMap<VariableId, Type>> {
+        match self {
+            Type::ParametricType(id, params) => {
+                let vars = &ctx.get_parametric(*id).unwrap().params;
+                Some(vars.iter().zip(params).map(|(v, p)| (*v, p.clone())).collect())
+            },
+            _ => None
+        }
+    }
+}