From ea5991732cfc935a401b7a30423a66f2c253defd Mon Sep 17 00:00:00 2001
From: bog <bog@gozmail.net>
Date: Tue, 12 Sep 2023 11:05:34 +0200
Subject: [PATCH] ADD: recursive functions.

---
 examples/fun.gri | 15 ++++++++++++++-
 src/Compiler.cpp | 13 +++++++++++++
 src/Compiler.hpp |  1 +
 src/VM.cpp       |  5 ++++-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/examples/fun.gri b/examples/fun.gri
index 9c73d6e..af17598 100644
--- a/examples/fun.gri
+++ b/examples/fun.gri
@@ -15,4 +15,17 @@
 
 ;; inner variable
 ($ (d x) ($ y 3) (+ x y))
-(assert-eq? 7 (d 4))
\ No newline at end of file
+(assert-eq? 7 (d 4))
+
+;; recursivity
+($ (e n)
+  (if (eq? 0 n) 1
+      (* n (e (- n 1)))))
+
+(assert-eq? 120 (e 5))
+
+;; self keyword
+(assert-eq? 720 ((-> (x)
+            (if (eq? x 0)
+                1
+                (* x (self (- x 1))))) 6))
diff --git a/src/Compiler.cpp b/src/Compiler.cpp
index a9e196f..5bc2436 100644
--- a/src/Compiler.cpp
+++ b/src/Compiler.cpp
@@ -94,6 +94,16 @@ namespace grino
                         m_scope.size());
           }
 
+        std::string name = "self";
+
+        if (!m_decl_context.empty())
+          {
+            name = m_decl_context.back();
+          }
+
+        sym.declare(node->loc(), name, get_local_address(),
+                    m_scope.size());
+
         auto prog = std::make_shared<Program>();
         auto body = node->child(1).lock();
         compile(body, *prog, sym);
@@ -128,9 +138,12 @@ namespace grino
         auto expr = node->child(1).lock();
         size_t address = get_local_address();
 
+        m_decl_context.push_back(ident);
         compile(expr, program, sym);
+        m_decl_context.pop_back();
 
         sym.declare(node->loc(), ident, address, m_scope.size());
+
         program.push_instr(OPCODE_STORE_LOCAL, address);
       } break;
 
diff --git a/src/Compiler.hpp b/src/Compiler.hpp
index 522a8ae..4e1f555 100644
--- a/src/Compiler.hpp
+++ b/src/Compiler.hpp
@@ -33,6 +33,7 @@ namespace grino
                        std::shared_ptr<StaticFunction>> m_statics;
 
     std::vector<size_t> m_scope;
+    std::vector<std::string> m_decl_context;
 
     size_t get_local_address();
     void enter_scope(bool reset=false);
diff --git a/src/VM.cpp b/src/VM.cpp
index 68fcaf8..4d432a1 100644
--- a/src/VM.cpp
+++ b/src/VM.cpp
@@ -127,7 +127,8 @@ namespace grino
                 args.insert(std::begin(args), program().constant(pop()));
               }
 
-            size_t ref = program().constant(pop())->as_ref();
+            auto ref_val = program().constant(pop());
+            size_t ref = ref_val->as_ref();
             auto fun = heap(ref)->as_function();
 
             if (fun->is_native())
@@ -149,6 +150,8 @@ namespace grino
                     set_local(i, args[i]);
                   }
 
+                set_local(args.size(), ref_val);
+
                 m_pc = 0;
               }
           } break;