From 8b3a9b8f0d80e7dd789f363deb6bb36189a31f01 Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Sun, 18 May 2025 08:17:20 -0700
Subject: Add a typechecker

---
 Syntax.sml | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 53 insertions(+), 3 deletions(-)

(limited to 'Syntax.sml')

diff --git a/Syntax.sml b/Syntax.sml
index 5d45133..0d10dd2 100644
--- a/Syntax.sml
+++ b/Syntax.sml
@@ -15,7 +15,8 @@ struct
   | PCon of string list * pat
 
   datatype expr =
-    EIdent of string list
+    EIdent of string
+  | EDot of structExpr * string
   | EBuiltin of string
   | EInt of int
   | EStr of string
@@ -33,14 +34,63 @@ struct
     DVal of pat * expr
   | DValRec of pat * expr
   | DFun of string * (pat list * expr) list
-  | DDatatype of string * (string * etype option) list
+  | DDatatype of string list * string * (string * etype option) list
   | DType of string * etype
   | DStruct of string * structExpr
 
   and structExpr =
-    SIdent of string list
+    SIdent of string
+  | SDot of structExpr * string
   | SStruct of dec list
 
+  datatype ty =
+    TInt
+  | TBool
+  | TString
+  | TVar of int
+  | TTuple of ty list
+  | TFun of ty * ty
+  | TList of ty
+  | TDatatype of string list
+
+  datatype structType =
+    TStruct of (string * structType) list * (string * ty) list
+(*| TFunctor of structType * structType *)
+
+  datatype typedPat =
+    TPWild
+  | TPVar of string
+  | TPInt of int
+  | TPTuple of (typedPat * ty) list
+  | TPCon of string list * (typedPat * ty)
+
+  datatype typedExpr =
+    TEIdent of string
+  | TEDot of (typedStructExpr * structType) * string
+  | TEBuiltin of string
+  | TEInt of int
+  | TEStr of string
+  | TETuple of (typedExpr * ty) list
+  | TEList of (typedExpr * ty) list
+  | TEApp of (typedExpr * ty) * (typedExpr * ty)
+  | TEAndAlso of (typedExpr * ty) * (typedExpr * ty)
+  | TEOrElse of (typedExpr * ty) * (typedExpr * ty)
+  | TELet of typedDec list * (typedExpr * ty)
+  | TELambda of (typedPat * ty) * (typedExpr * ty)
+  | TECase of (typedExpr * ty) * ((typedPat * ty) * (typedExpr * ty)) list
+
+  and typedDec =
+    TDVal of (typedPat * ty) * (typedExpr * ty)
+  | TDValRec of (typedPat * ty) * (typedExpr * ty)
+  | TDFun of string * ((typedPat * ty) list * (typedExpr * ty)) list
+  | TDDatatype of string * (string * ty option) list
+  | TDStruct of string * (typedStructExpr * structType)
+
+  and typedStructExpr =
+    TSIdent of string
+  | TSDot of (typedStructExpr * structType) * string
+  | TSStruct of typedDec list
+
   (* Lambda language *)
   type var = int
 
-- 
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