Fix: quote is not a typewise identity function. Added vt(&str) as util for VarType(String).

5 files changed, 12 insertions, 4 deletions

diff --git a/src/type/check.rs b/src/type/check.rs
index 81a43a4..c3bdcb4 100644
--- a/src/type/check.rs
+++ b/src/type/check.rs
@@ -28,7 +28,7 @@ impl SExp {
     ///
     /// assert_eq!(
     ///     scons(Quote, scons(1, scons(False, Nil))).type_check(),
-    ///     Ok(List(vec![Integer, Boolean]))
+    ///     Ok(List(vec![QuoteTy, List(vec![Integer, Boolean])]))
     /// );
     /// ```
     /// Though so is Nil given too:
@@ -150,8 +150,8 @@ impl SExp {
             Atom(Not)   => Ok(arr(List(vec!(Boolean)), Boolean)),
             Atom(Nil)   => Ok(List(vec![])),
             Atom(Quote) => Ok(arr(
-                               VarType("T".to_string()),
-                               VarType("T".to_string())
+                               vt("T"),
+                               List(vec![QuoteTy, vt("T")])
                            )),
 
             SCons(op, l) => {
diff --git a/src/type/display.rs b/src/type/display.rs
index 3e4f49c..8eb0647 100644
--- a/src/type/display.rs
+++ b/src/type/display.rs
@@ -19,6 +19,7 @@ impl fmt::Display for Type {
         match self {
             Integer     => write!(f, "{}", "Int"),
             Boolean     => write!(f, "{}", "Bool"),
+            QuoteTy     => write!(f, "{}", "Quote"),
             Arrow(a, b) => write!(f, "({} -> {})", a, b),
             List(types) => write!(
                                f,
diff --git a/src/type/mod.rs b/src/type/mod.rs
index e4c0841..e29e069 100644
--- a/src/type/mod.rs
+++ b/src/type/mod.rs
@@ -16,6 +16,8 @@ pub enum Type {
 
     Boolean,
 
+    QuoteTy,
+
     Arrow(Box<Type>, Box<Type>),
 
     List(Vec<Type>),
@@ -92,6 +94,7 @@ impl Type {
         match self {
             Integer => Ok(()),
             Boolean => Ok(()),
+            QuoteTy => Ok(()),
             Arrow(a, b) => b.is_concrete().and_then(|_ok| a.is_concrete()),
             List(v) => {
                 let mut res = Ok(());
diff --git a/src/type/subst.rs b/src/type/subst.rs
index 79c5fe1..d63f71b 100644
--- a/src/type/subst.rs
+++ b/src/type/subst.rs
@@ -38,8 +38,8 @@ impl Type {
             VarType(s) => VarType(s),
 
             Integer => Integer,
-
             Boolean => Boolean,
+            QuoteTy => QuoteTy,
 
         }
     }
diff --git a/src/type/util.rs b/src/type/util.rs
index 27fc661..9be8c6e 100644
--- a/src/type/util.rs
+++ b/src/type/util.rs
@@ -5,3 +5,7 @@ pub fn arr(a: impl Into<Box<Type>>, b: impl Into<Box<Type>>) -> Type {
     Arrow(a.into(), b.into())
 }
 
+pub fn vt(name: &str) -> Type {
+    VarType(name.to_string())
+}
+