feat: initial support of closures

Also detection and automatic execution of main function.
Make sure that all debug is output to stderr.

3 files changed, 8 insertions, 5 deletions

diff --git a/vm/type.go b/vm/type.go
index d29de48..16e3733 100644
--- a/vm/type.go
+++ b/vm/type.go
@@ -26,6 +26,9 @@ type Value struct {
 
 // NewValue returns an addressable zero value for the specified type.
 func NewValue(typ *Type) Value {
+	if typ.Rtype.Kind() == reflect.Func {
+		typ = TypeOf(0) // Function value is its index in the code segment.
+	}
 	return Value{Type: typ, Data: reflect.New(typ.Rtype).Elem()}
 }
 
diff --git a/vm/vm.go b/vm/vm.go
index a8c1f28..6472dae 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -145,7 +145,7 @@ func (m *Machine) Run() (err error) {
 		case Calli:
 			mem = append(mem, ValueOf(ip+1), ValueOf(fp))
 			fp = sp + 2
-			ip += int(op[2])
+			ip = int(op[2])
 			continue
 		case CallX: // Should be made optional.
 			l := int(op[2])
diff --git a/vm/vm_test.go b/vm/vm_test.go
index fb71176..8fa8e71 100644
--- a/vm/vm_test.go
+++ b/vm/vm_test.go
@@ -75,7 +75,7 @@ var tests = []struct {
 		{0, Push, 3},      // 1
 		{0, Return, 1, 1}, // 2
 		{0, Push, 1},      // 3
-		{0, Calli, -3},    // 4
+		{0, Calli, 1},     // 4
 		{0, Exit},         // 5
 	},
 	start: 0, end: 1, mem: "[3]",
@@ -138,16 +138,16 @@ var tests = []struct {
 		{0, JumpTrue, 9},  // 3  [], goto 12
 		{0, Fdup, -2},     // 4  [i]
 		{0, Subi, 2},      // 5  [(i-2)]
-		{0, Calli, -5},    // 6  [fib(i-2)]
+		{0, Calli, 1},     // 6  [fib(i-2)]
 		{0, Fdup, -2},     // 7  [fib(i-2) i]
 		{0, Subi, 1},      // 8  [(i-2) (i-1)]
-		{0, Calli, -8},    // 9  [fib(i-2) fib(i-1)], call 1
+		{0, Calli, 1},     // 9  [fib(i-2) fib(i-1)], call 1
 		{0, Add},          // 10 [fib(i-2)+fib(i-1)]
 		{0, Return, 1, 1}, // 11 return i
 		{0, Fdup, -2},     // 12 [i]
 		{0, Return, 1, 1}, // 13 return i
 		{0, Push, 6},      // 14 [1]
-		{0, Calli, -14},   // 15 [fib(*1)], call 1
+		{0, Calli, 1},     // 15 [fib(*1)], call 1
 		{0, Exit},         // 16
 	},
 	start: 0, end: 1, mem: "[8]",