ADD: set! function.

ADD: function can returns other function or lambda.

examples/fun.gri

@@ -16,3 +16,37 @@
 ;; inner variable
 ($ (d x) ($ y 3) (+ x y))
 (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))
+
+;; inner functions
+($ (f n)
+  ($ (inner n) (+ n 1))
+  (inner (inner n)))
+
+(assert-eq? 3 (f 1))
+
+;; return function
+($ (g)
+   ($ (inner n) (* 7 n))
+   inner)
+
+(assert-eq? 42 ( (g) 6 ))
+
+;; return lambda
+($ (h)
+   (-> (n)
+       (* 3 (- n 2))))
+
+(assert-eq? 15 ( (h) 7 ))

examples/set.gri

@@ -0,0 +1,10 @@
+($ a 1)
+(set! a 2)
+(assert-eq? 2 a )
+
+($ (b x) (+ x 1))
+($ (c x) (* x 2))
+($ d b)
+(assert-eq? 3 (d 2))
+(set! d c)
+(assert-eq? 4 (d 2))

lib/core.cpp

@@ -1,6 +1,7 @@
 #include "../src/Loader.hpp"
 #include "src/Logger.hpp"
 #include "src/Value.hpp"
+#include "src/opcodes.hpp"
 
 GRINO_ERROR(assertion_error);
 
@@ -345,6 +346,24 @@ extern "C" void lib(grino::Loader& loader)
     return grino::Value::make_nil(args.back()->loc());
   });
 
+  loader.add_static("set!", [](auto& compiler,
+                               auto node,
+                               auto& program,
+                               auto& sym){
+    std::string ident = node->child(1).lock()->repr();
+    auto expr = node->child(2).lock();
+
+    auto entry = sym.find(ident, compiler.scope());
+
+    if (entry)
+      {
+        compiler.compile(expr, program, sym);
+        program.push_instr(grino::OPCODE_STORE_LOCAL, entry->addr);
+      }
+
+    program.push_value(grino::Value::make_nil(node->loc()));
+  });
+
   loader.add_native("eq?", [](auto args){
     auto lhs = args.front();
 

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;
 

src/Compiler.hpp

@@ -20,6 +20,8 @@ namespace grino
     explicit Compiler(Logger& logger);
     virtual ~Compiler();
 
+    size_t scope() const { return m_scope.size(); }
+
     void compile(std::shared_ptr<Node> node,
                  Program& program,
                  SymTable& sym);
@@ -33,6 +35,7 @@ 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);

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;