diff --git a/src/crisp/core.cr b/src/crisp/core.cr
index 747b65b..dc050c6 100644
--- a/src/crisp/core.cr
+++ b/src/crisp/core.cr
@@ -1,7 +1,7 @@
 require "time"
 require "readline"
 
-require "./types"
+require "./expr"
 require "./error"
 require "./printer"
 require "./reader"
diff --git a/src/crisp/env.cr b/src/crisp/env.cr
index 26f50a9..1dea91c 100644
--- a/src/crisp/env.cr
+++ b/src/crisp/env.cr
@@ -1,4 +1,4 @@
-require "./types"
+require "./expr"
 require "./error"
 
 module Crisp
diff --git a/src/crisp/evaluator.cr b/src/crisp/evaluator.cr
index 4fa189f..c2aafb5 100644
--- a/src/crisp/evaluator.cr
+++ b/src/crisp/evaluator.cr
@@ -3,7 +3,7 @@ require "readline"
 
 require "./reader"
 require "./printer"
-require "./types"
+require "./expr"
 require "./env"
 require "./core"
 require "./error"
diff --git a/src/crisp/types.cr b/src/crisp/expr.cr
similarity index 92%
rename from src/crisp/types.cr
rename to src/crisp/expr.cr
index fb2898a..0b6ab54 100644
--- a/src/crisp/types.cr
+++ b/src/crisp/expr.cr
@@ -40,14 +40,14 @@ module Crisp
 
   class Expr
     alias Func = (Array(Expr) -> Expr)
-    alias ValueExpr = Nil | Bool | Int32 | String | Symbol | List | Vector | HashMap | Func | Closure | Atom
+    alias Type = Nil | Bool | Int32 | String | Symbol | List | Vector | HashMap | Func | Closure | Atom
 
     is_macro :: Bool
     meta :: Expr
 
     property :is_macro, :meta
 
-    def initialize(@val : ValueExpr)
+    def initialize(@val : Type)
       @is_macro = false
       @meta = nil
     end
diff --git a/src/crisp/interpreter.cr b/src/crisp/interpreter.cr
index 489fae0..e9cbcaa 100644
--- a/src/crisp/interpreter.cr
+++ b/src/crisp/interpreter.cr
@@ -3,7 +3,7 @@ require "readline"
 
 require "./reader"
 require "./printer"
-require "./types"
+require "./expr"
 require "./env"
 require "./core"
 require "./error"
diff --git a/src/crisp/printer.cr b/src/crisp/printer.cr
index 4072751..15311d5 100644
--- a/src/crisp/printer.cr
+++ b/src/crisp/printer.cr
@@ -1,4 +1,4 @@
-require "./types"
+require "./expr"
 
 module Crisp
   class Printer
diff --git a/src/crisp/reader.cr b/src/crisp/reader.cr
index ddbcde9..7efc5c5 100644
--- a/src/crisp/reader.cr
+++ b/src/crisp/reader.cr
@@ -1,4 +1,4 @@
-require "./types"
+require "./expr"
 require "./error"
 
 module Crisp