Add first draft of Idris post

code/typesafe-interpreter/TypesafeIntr.idr

@@ -43,7 +43,7 @@ typecheck (BinOp o l r) = do
   (ot ** f) <- typecheckOp o lt rt
   pure (_ ** BinOperation f le re)
 
-eval : {t : ExprType} -> SafeExpr t -> repr t
+eval : SafeExpr t -> repr t
 eval (IntLiteral i) = i
 eval (BoolLiteral b) = b
 eval (StringLiteral s) = s
@@ -58,7 +58,7 @@ tryEval : Expr -> String
 tryEval ex =
   case typecheck ex of
     Left err => "Type error: " ++ err
-    Right (t ** e) => resultStr $ eval {t=t} e
+    Right (t ** e) => resultStr $ eval {t} e
 
 main : IO ()
 main = putStrLn $ tryEval $ BinOp Add (IntLit 6) (BinOp Multiply (IntLit 160) (IntLit 2))