Each pointer needs its own stack, merging the two packages to avoid a circular dependency

pkg/interpreter/interpreter.go

@@ -25,7 +25,8 @@ func (i *Interpreter) Run() {
 func (i *Interpreter) Step() {
 	var prev *pointer.Pointer = nil
 	for p := i.p; p != nil; p = p.Next {
-		switch p.Get(*i.f) {
+		c := p.Get(*i.f)
+		switch c {
 		case '@':
 			if prev == nil {
 				i.p = p.Next
@@ -33,8 +34,13 @@ func (i *Interpreter) Step() {
 				prev.Next = p.Next
 			}
 			break
+		case '#':
+			p.Step(*i.f)
 		default:
-			log.Fatalf("Non implemented instruction code %d : %c", p.Get(*i.f), p.Get(*i.f))
+			if !p.Redirect(c) {
+				log.Fatalf("Non implemented instruction code %d : %c", c, c)
+			}
 		}
+		p.Step(*i.f)
 	}
 }

pkg/interpreter/interpreter_test.go

@@ -0,0 +1,50 @@
+package interpreter
+
+import (
+	"os"
+	"testing"
+
+	"git.adyxax.org/adyxax/gofunge/pkg/field"
+	"git.adyxax.org/adyxax/gofunge/pkg/pointer"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRun(t *testing.T) {
+	file, err := os.Open("../field/test_data/minimal.b98")
+	require.NoError(t, err)
+	defer file.Close()
+	f, err := field.Load(file)
+	require.NoError(t, err)
+	NewInterpreter(f, pointer.NewPointer()).Run()
+}
+
+func TestStep(t *testing.T) {
+	testCases := []struct {
+		name            string
+		filename        string
+		pointer         *pointer.Pointer
+		expectedField   *field.Field
+		expectedPointer *pointer.Pointer
+	}{
+		{"minimal", "../field/test_data/minimal.b98", nil, nil, nil},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			file, err := os.Open(tc.filename)
+			require.NoError(t, err)
+			defer file.Close()
+			f, err := field.Load(file)
+			require.NoError(t, err)
+			if tc.pointer == nil {
+				tc.pointer = pointer.NewPointer()
+			}
+			NewInterpreter(f, tc.pointer).Step()
+			if tc.expectedField != nil {
+				require.Equal(t, tc.expectedField, f)
+			}
+			if tc.expectedPointer != nil {
+				require.Equal(t, tc.expectedPointer, tc.pointer)
+			}
+		})
+	}
+}