feat: Implement eval methods for expressions

lib/syntax/Statements.ml

@@ -1,13 +1,52 @@
-open Expressions
+class virtual statement =
+  object
+    inherit Node.node
+    method virtual check_type : Environments.typeEnvironments -> Types.t
+    method virtual eval : Environments.evalEnvironment -> Literals.literal_value
+  end
 
-type statements =
-  | SequenceStatement of statements * statements
-  | ExpressionStatement of expressions
+class sequence (left : statement) (right : statement) =
+  object
+    inherit statement
 
-let rec pp_statements = function
-  | SequenceStatement (stmt1, stmt2) ->
-      let pp_stmt1 = pp_statements stmt1 and pp_stmt2 = pp_statements stmt2 in
-      Printf.sprintf "SequenceStatement(%s, %s)" pp_stmt1 pp_stmt2
-  | ExpressionStatement expr ->
-      let pp_expr = pp_expressions expr in
-      Printf.sprintf "ExpressionStatement(%s)" pp_expr
+    method to_string =
+      "Sequence(" ^ left#to_string ^ ", " ^ right#to_string ^ ")"
+
+    method check_type env =
+      let _ = left#check_type env in
+      right#check_type env
+
+    method eval env =
+      let _ = left#eval env in
+      right#eval env
+  end
+
+class expression (expression : Expressions.expression) =
+  object
+    inherit statement
+    method to_string = "Expression(" ^ expression#to_string ^ ")"
+    method check_type env = expression#check_type env
+    method eval env = expression#eval env
+  end
+
+class variableDeclaration (name : string) (tp : Types.t)
+  (expression : Expressions.expression) =
+  object
+    inherit statement
+
+    method to_string =
+      "VariableDeclaration(" ^ name ^ ", " ^ Types.string_of_t tp ^ ", "
+      ^ expression#to_string ^ ")"
+
+    method check_type env =
+      let expression_type = expression#check_type env in
+      if tp = expression_type then (
+        env#add name expression_type;
+        Types.VoidType)
+      else raise (Failure "VariableDeclaration: type mismatch")
+
+    method eval env =
+      let value = expression#eval env in
+      env#add name value;
+      value
+  end