diff --git a/schala-lang/language/src/builtin.rs b/schala-lang/language/src/builtin.rs
index 7eea68f..3927d99 100644
--- a/schala-lang/language/src/builtin.rs
+++ b/schala-lang/language/src/builtin.rs
@@ -1,5 +1,6 @@
 use std::rc::Rc;
 use std::collections::HashMap;
+use std::str::FromStr;
 
 use crate::tokenizing::TokenKind;
 use crate::typechecking::{TypeConst, Type};
@@ -8,7 +9,6 @@ use crate::typechecking::{TypeConst, Type};
 enum Builtin {
   Add,
   Subtract,
-  Negate,
   Multiply,
   Divide,
   Quotient,
@@ -21,14 +21,51 @@ enum Builtin {
   BooleanNot,
   Equality,
   LessThan,
-  LessThanEquals,
+  LessThanOrEqual,
   GreaterThan,
-  GreaterThanEquals,
+  GreaterThanOrEqual,
   Comparison,
   FieldAccess,
   IOPrint,
   IOPrintLn,
   IOGetLine,
+  Assignment,
+  Concatenate,
+}
+
+impl FromStr for Builtin {
+  type Err = ();
+
+  fn from_str(s: &str) -> Result<Self, Self::Err> {
+    use Builtin::*;
+    Ok(match s {
+      "+" => Add,
+      "-" => Subtract,
+      "*" => Multiply,
+      "/" => Divide,
+      "quot" => Quotient,
+      "%" => Modulo,
+      "++" => Concatenate,
+      "^" =>  Exponentiation,
+      "&" => BitwiseAnd,
+      "&&" => BooleanAnd,
+      "|" => BitwiseOr,
+      "||" => BooleanOr,
+      "!" => BooleanNot,
+      ">" => GreaterThan,
+      ">=" => GreaterThanOrEqual,
+      "<" => LessThan,
+      "<=" => LessThanOrEqual,
+      "==" => Equality,
+      "=" => Assignment,
+      "<=>" => Comparison,
+      "." => FieldAccess,
+      "print" => IOPrint,
+      "println" => IOPrintLn,
+      "getline" => IOGetLine,
+      _ => return Err(())
+    })
+  }
 }
 
 #[derive(Debug, PartialEq, Clone)]