diff --git a/src/schala_lang/builtin.rs b/src/schala_lang/builtin.rs
index c2d5df0..f4076ba 100644
--- a/src/schala_lang/builtin.rs
+++ b/src/schala_lang/builtin.rs
@@ -1,15 +1,14 @@
 use std::rc::Rc;
+use std::collections::HashMap;
+
+use schala_lang::typechecking::{Type, TypeResult, TConst};
+use self::Type::*; use self::TConst::*;
 
 #[derive(Debug, PartialEq, Clone)]
 pub struct BinOp {
   sigil: Rc<String>
 }
 
-#[derive(Debug, PartialEq, Clone)]
-pub struct PrefixOp {
-  sigil: Rc<String>
-}
-
 impl BinOp {
   pub fn from_sigil(sigil: Rc<String>) -> BinOp {
     BinOp { sigil }
@@ -17,10 +16,16 @@ impl BinOp {
   pub fn sigil(&self) -> &Rc<String> {
     &self.sigil
   }
+  pub fn get_type(&self) -> TypeResult<Type> {
+    let s = self.sigil.as_str();
+    BINOPS.get(s).map(|x| x.0.clone()).ok_or(format!("Binop {} not found", s))
+  }
+}
+
+impl BinOp {
   pub fn min_precedence() -> i32 {
     i32::min_value()
   }
-
   pub fn get_precedence(op: &str) -> i32 {
     match op {
       "+" | "-" => 10,
@@ -30,6 +35,11 @@ impl BinOp {
   }
 }
 
+#[derive(Debug, PartialEq, Clone)]
+pub struct PrefixOp {
+  sigil: Rc<String>
+}
+
 impl PrefixOp {
   pub fn from_sigil(sigil: Rc<String>) -> PrefixOp {
     PrefixOp { sigil }
@@ -44,3 +54,18 @@ impl PrefixOp {
     }
   }
 }
+
+
+/* the second tuple member is a placeholder for when I want to make evaluation rules tied to the
+ * binop definition */
+lazy_static! {
+  static ref BINOPS: HashMap<&'static str, (Type, (), i32)> =
+    hashmap! {
+      "+" => (Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))), (), 10),
+      "-" => (Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))), (), 10),
+      "*" => (Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))), (), 20),
+      "/" => (Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))), (), 20),
+      "%" => (Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))), (), 20),
+      "++" => (Func(bx!(Const(StringT)), bx!(Func(bx!(Const(StringT)), bx!(Const(StringT))))), (), 30),
+    };
+}
diff --git a/src/schala_lang/typechecking.rs b/src/schala_lang/typechecking.rs
index a160052..50e641e 100644
--- a/src/schala_lang/typechecking.rs
+++ b/src/schala_lang/typechecking.rs
@@ -2,7 +2,6 @@ use std::rc::Rc;
 use std::collections::HashMap;
 
 use schala_lang::parsing;
-use schala_lang::builtin;
 
 pub struct TypeContext { 
   bindings: HashMap<Rc<String>, Type>
@@ -45,7 +44,7 @@ impl parsing::TypeName {
   }
 }
 
-type TypeResult<T> = Result<T, String>;
+pub type TypeResult<T> = Result<T, String>;
 
 impl TypeContext {
   pub fn new() -> TypeContext {
@@ -100,7 +99,7 @@ impl TypeContext {
       &StringLiteral(_) => Ok(Const(StringT)),
       &BoolLiteral(_) => Ok(Const(Bool)),
       &BinExp(ref op, ref lhs, ref rhs) => { /* remember there are both the haskell convention talk and the write you a haskell ways to do this! */
-        match self.infer_optype(op)? {
+        match op.get_type()? {
           Func(box t1, box Func(box t2, box t3)) => {
             let lhs_ty = self.infer(lhs)?;
             let rhs_ty = self.infer(rhs)?;
@@ -130,11 +129,6 @@ impl TypeContext {
       _ => Err(format!("Type not yet implemented"))
     }
   }
-  fn infer_optype(&mut self, _op: &builtin::BinOp) -> TypeResult<Type> {
-    use self::Type::*; use self::TConst::*;
-    //this is a shim; not all ops are binops from int -> int -> int
-    Ok(Func(bx!(Const(Int)), bx!(Func(bx!(Const(Int)), bx!(Const(Int))))))
-  }
   fn unify(&mut self, t1: Type, t2: Type) -> TypeResult<Type> {
     use self::Type::*;// use self::TConst::*;
     match (t1, t2) {