From 60d607cb592c88f143f281cae552e2a6c8dd0e81 Mon Sep 17 00:00:00 2001
From: Emin Arslan <me@emin.engineer>
Date: Sun, 17 May 2026 20:45:49 +0300
Subject: [PATCH] compiler and vm: added subtraction

---
 lib/compiler/scope_analysis.ml |  3 ++-
 lib/vm/native.ml               | 18 ++++++++++++++----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/lib/compiler/scope_analysis.ml b/lib/compiler/scope_analysis.ml
index 100e859..7b59bf1 100644
--- a/lib/compiler/scope_analysis.ml
+++ b/lib/compiler/scope_analysis.ml
@@ -58,7 +58,8 @@ type expression =
 let default_global_table =
   SymbolTable.of_list [
       ("PRINT", (0, Native 0));
-      ("ADD", (1, Native 1))
+      ("+", (1, Native 1));
+      ("-", (2, Native 2))
     ]
 
 (* extract all defined global symbols, given the top-level expressions
diff --git a/lib/vm/native.ml b/lib/vm/native.ml
index ed16107..9072e71 100644
--- a/lib/vm/native.ml
+++ b/lib/vm/native.ml
@@ -23,20 +23,30 @@ let numeric_add = function
   | NDouble x -> (function
                   | NInt y -> NDouble (x+.(float_of_int y))
                   | NDouble y -> NDouble (x+.y))
-
+let numeric_sub = function
+  | NInt x -> (function
+               | NInt y -> NInt (x - y)
+               | NDouble y -> NDouble ((float_of_int x) -. y))
+  | NDouble x -> (function
+                  | NInt y -> NDouble (x-.(float_of_int y))
+                  | NDouble y -> NDouble (x-.y))
 
 let builtin_print (v : Types.value ref list) =
   List.iter (fun r -> print_endline (print_value !r)) v;
   Types.Nil
 
-
-
 let builtin_add (vs : Types.value ref list) =
   of_numeric (List.fold_left numeric_add (NInt 0) (List.map (fun r -> to_numeric !r) vs))
+let builtin_sub (vs : Types.value ref list) =
+  match vs with
+  | f :: rest -> of_numeric (List.fold_left numeric_sub (to_numeric !f) (List.map (fun r -> to_numeric !r) rest))
+  | [] -> failwith "invalid number of arguments for subtraction"
+
 
 let table = [|
     builtin_print;
-    builtin_add
+    builtin_add;
+    builtin_sub
   |]