diff --git a/forge/forge.go b/forge/forge.go
index 59e8311..016f4a1 100644
--- a/forge/forge.go
+++ b/forge/forge.go
@@ -1,2 +1,75 @@
 // Package forge implements sort of a stack-based interpreter.
 package forge
+
+import (
+	"io"
+	"os"
+
+	"git.sr.ht/~cco/go-scopes/common/ptr"
+	"git.sr.ht/~cco/go-scopes/common/stack"
+	"git.sr.ht/~cco/go-scopes/common/voc"
+)
+
+type DataItem interface{}
+
+type Ptr = ptr.Ptr[DataItem]
+type Stack = stack.Stack[DataItem]
+type Voc = voc.Vocabulary[XT]
+
+type Callable func(*ForgeEnv, *Item)
+
+type Item struct {
+	name      string
+	immediate bool
+	fct       Callable
+	body      Ptr
+}
+
+type XT = *Item
+
+type ForgeEnv struct {
+	ds, rs     Stack
+	cp, ip, dp Ptr
+	voc        *Voc
+	latestXT   XT
+	cstate     bool
+	output     io.Writer
+}
+
+func NewVoc(parent *Voc) *Voc {
+	return voc.NewVoc[XT](parent)
+}
+
+func NewFE() *ForgeEnv {
+	return newFE(NewVoc(nil))
+}
+
+func (f *ForgeEnv) ChildFE() *ForgeEnv {
+	return newFE(NewVoc(f.voc))
+}
+
+func newFE(voc *Voc) *ForgeEnv {
+	return &ForgeEnv{
+		ds:     stack.NewStack[DataItem](),
+		rs:     stack.NewStack[DataItem](),
+		ip:     ptr.NewSlice[DataItem](),
+		voc:    voc,
+		output: os.Stdout,
+	}
+}
+
+// ForgeEnv methods
+
+func (f *ForgeEnv) Exec() {
+}
+
+// dummy stuff for testing
+
+var builtins = struct{ add, sub XT }{}
+
+var work = struct{ square XT }{}
+
+func init() {
+	builtins.add = &Item{}
+	builtins.sub = &Item{}
+}
diff --git a/tests/forge_test.go b/tests/forge_test.go
new file mode 100644
index 0000000..0bf359e
--- /dev/null
+++ b/tests/forge_test.go
@@ -0,0 +1,18 @@
+package scopes_test
+
+import (
+	tbase "testing"
+
+	"git.sr.ht/~cco/go-scopes/common/testing"
+	"git.sr.ht/~cco/go-scopes/forge"
+)
+
+func TestForge(tb *tbase.T) {
+	t := testing.SetUp(tb)
+	t.Run("exec", ExecTest)
+}
+
+func ExecTest(t *testing.T) {
+	fe := forge.NewFE()
+	fe.Exec()
+}