From b29331c24659eccf6ae9cc003f7d276ab02bc4de Mon Sep 17 00:00:00 2001
From: monoid <qaswedfr55@gmail.com>
Date: Wed, 29 Jan 2025 20:44:36 +0900
Subject: [PATCH] feat: tab indent `expr2str`

---
 lib/eval.ml   |  3 ---
 lib/parser.ml | 21 +++++++++++----------
 2 files changed, 11 insertions(+), 13 deletions(-)

diff --git a/lib/eval.ml b/lib/eval.ml
index 8f1f7cb..b958f2f 100644
--- a/lib/eval.ml
+++ b/lib/eval.ml
@@ -1,8 +1,5 @@
-
-
 module VariableBindingMap = Map.Make(String)
 
-
 type value_type = 
 | Int of int
 | Fun of function_type
diff --git a/lib/parser.ml b/lib/parser.ml
index a55d181..d0ff5ae 100644
--- a/lib/parser.ml
+++ b/lib/parser.ml
@@ -94,17 +94,18 @@ and expr_tree =
   | Number of int
 
 let expr2str (e: expr_tree): string = 
-  let rec aux e = 
+  let tab n = String.make (n * 2) ' ' in
+  let rec aux e depth = 
     match e with
-    | LetExpr (Let (id, e1, e2)) -> Printf.sprintf "let %s = %s in\n %s" id (aux e1) (aux e2)
-    | FunExpr (Fun (id, e)) -> Printf.sprintf "fun %s -> %s" id (aux e)
-    | IfExpr (If (e1, e2, e3)) -> Printf.sprintf "if %s then %s else %s" (aux e1) (aux e2) (aux e3)
-    | CallExpr (Call (e1, e2)) -> Printf.sprintf "%s %s" (aux e1) (aux e2)
-    | BinOpExpr (op, e1, e2) -> Printf.sprintf "%s %s %s" (aux e1) (Lexer.op2str op) (aux e2)
-    | MonoOpExpr (op, e) -> Printf.sprintf "%s %s" (Lexer.op2str op) (aux e)
+    | LetExpr (Let (id, e1, e2)) -> Printf.sprintf "let %s = %s in\n%s%s" id (aux e1 depth) (tab depth) (aux e2 (depth+1))
+    | FunExpr (Fun (id, e)) -> Printf.sprintf "fun %s ->\n%s%s" id (tab depth) (aux e (depth+1))
+    | IfExpr (If (e1, e2, e3)) -> Printf.sprintf "if %s then\n%s%selse\n%s%s" (aux e1 depth) (tab depth) (aux e2 depth) (tab depth) (aux e3 depth)
+    | CallExpr (Call (e1, e2)) -> Printf.sprintf "%s %s" (aux e1 depth) (aux e2 depth)
+    | BinOpExpr (op, e1, e2) -> Printf.sprintf "%s %s %s" (aux e1 depth) (Lexer.op2str op) (aux e2 depth)
+    | MonoOpExpr (op, e) -> Printf.sprintf "%s %s" (Lexer.op2str op) (aux e depth)
     | Identifier id -> id
     | Number n -> string_of_int n in
-  aux e
+  aux e 0
 
 let rec parse_let_expr (): let_expr_tree parser = 
   let* _ = match_token (Lexer.Keyword Lexer.Let) in
@@ -212,8 +213,8 @@ let get_expr_tree_from_tokens (tokens: Lexer.token Seq.t): expr_tree option =
   | None -> None
 
 let%test "test get_expr_tree_from_tokens 1" =
-  let tokens = Lexer.lex_tokens_seq "let x = 1 in x" in
+  let tokens = Lexer.lex_tokens_seq "let x = 1 in\n  x" in
   let tokens = tokens |> Seq.map (fun (x,_) -> x) in
   match get_expr_tree_from_tokens tokens with
-  | Some e -> expr2str e = "let x = 1 in\n x"
+  | Some e -> expr2str e = "let x = 1 in\n  x"
   | None -> false