From c724ad89bd4813e872b58c5ccf81432c031ecd5a Mon Sep 17 00:00:00 2001
From: Helmut Merz <helmutm@cy55.de>
Date: Sun, 23 Jul 2023 10:20:25 +0200
Subject: [PATCH] forge: execute simple forge code

---
 forge/builtins/builtins.go | 19 +++++++++----
 forge/forge.go             | 58 ++++++++++++++++++++++----------------
 tests/forge_test.go        |  8 ++----
 3 files changed, 49 insertions(+), 36 deletions(-)

diff --git a/forge/builtins/builtins.go b/forge/builtins/builtins.go
index 70e7bc6..adfa172 100644
--- a/forge/builtins/builtins.go
+++ b/forge/builtins/builtins.go
@@ -9,15 +9,22 @@ type builtins struct {
 	Add, Lit XT
 }
 
-func Setup(f FE) *builtins {
+func Get(f FE) *builtins {
+	m := f.Voc().Lookup("builtins")
+	if m.IsNothing() {
+		b := setup(f)
+		f.Voc().Register("builtins", b)
+		return b
+	}
+	return m.Value().(*builtins)
+}
+
+func setup(f FE) *builtins {
 	r := func(name string, fct forge.Callable) XT {
 		return forge.Register(f.Voc(), name, fct)
 	}
 	return &builtins{
-		Lit: r("literal", literal),
+		Add: r("+", func(f FE, _ XT) { f.Push(f.Pop().(int) + f.Pop().(int)) }),
+		Lit: r("literal", func(f FE, _ XT) { f.Literal() }),
 	}
 }
-
-func literal(f FE, it XT) {
-	f.Push(f.IP().Next().Value())
-}
diff --git a/forge/forge.go b/forge/forge.go
index 730dba2..9be7085 100644
--- a/forge/forge.go
+++ b/forge/forge.go
@@ -14,19 +14,10 @@ type fitem interface{}
 
 type fptr = ptr.Ptr[fitem]
 type fstack = stack.Stack[fitem]
-type fvoc = voc.Vocabulary[XT]
+type fvoc = voc.Vocabulary[fitem]
 
 type Callable func(*forgeEnv, XT)
 
-type xitem struct {
-	name      string
-	immediate bool
-	fct       Callable
-	body      fptr
-}
-
-type XT = *xitem
-
 type forgeEnv struct {
 	ds, rs     fstack
 	cp, ip, dp fptr
@@ -38,16 +29,12 @@ type forgeEnv struct {
 
 type FE = *forgeEnv
 
-func NewVoc(parent *fvoc) *fvoc {
-	return voc.NewVoc[XT](parent)
-}
-
 func NewFE() *forgeEnv {
-	return newFE(NewVoc(nil))
+	return newFE(newVoc(nil))
 }
 
 func (f *forgeEnv) ChildFE() *forgeEnv {
-	return newFE(NewVoc(f.voc))
+	return newFE(newVoc(f.voc))
 }
 
 func newFE(voc *fvoc) *forgeEnv {
@@ -60,7 +47,20 @@ func newFE(voc *fvoc) *forgeEnv {
 	}
 }
 
-// basic functions and methods
+var newVoc = voc.NewVoc[fitem]
+
+var newPtr = ptr.NewSlice[fitem]
+
+// xitem (executable item) / XT (execution token)
+
+type xitem struct {
+	name      string
+	immediate bool
+	fct       Callable
+	body      fptr
+}
+
+type XT = *xitem
 
 func Register(voc *fvoc, name string, fct Callable) *xitem {
 	it := xitem{
@@ -81,7 +81,7 @@ func (it *xitem) Immediate() {
 
 func (it *xitem) Body() fptr {
 	if it.body == nil {
-		it.body = ptr.NewSlice[fitem]()
+		it.body = newPtr()
 	}
 	return it.body
 }
@@ -90,22 +90,26 @@ func (it *xitem) Name() string {
 	return it.name
 }
 
-// ForgeEnv methods
+// forgeEnv methods
 
 func (f *forgeEnv) Voc() *fvoc {
 	return f.voc
 }
 
-func (f *forgeEnv) IP() fptr {
-	return f.ip
+func (f *forgeEnv) Code(items ...fitem) fptr {
+	code := newPtr(items...)
+	// ... pre-process (compile) code ...
+	return code
 }
 
-func (f *forgeEnv) Exec(items ...fitem) {
-	f.ip = ptr.NewSlice[fitem](items...)
+func (f *forgeEnv) Call(code fptr) {
+	f.rs.Push(f.ip)
+	f.ip = code.Clone()
 	for f.ip.Next() != nil {
-		it := f.ip.Value().(XT)
-		it.fct(f, it)
+		xt := f.ip.Value().(XT)
+		xt.fct(f, xt)
 	}
+	f.ip = f.rs.Pop().(fptr)
 }
 
 func (f *forgeEnv) Push(it fitem) {
@@ -115,3 +119,7 @@ func (f *forgeEnv) Push(it fitem) {
 func (f *forgeEnv) Pop() fitem {
 	return f.ds.Pop()
 }
+
+func (f *forgeEnv) Literal() {
+	f.Push(f.ip.Next().Value())
+}
diff --git a/tests/forge_test.go b/tests/forge_test.go
index d3996fe..4522758 100644
--- a/tests/forge_test.go
+++ b/tests/forge_test.go
@@ -15,9 +15,7 @@ func TestForge(tb *tbase.T) {
 
 func ExecTest(t *testing.T) {
 	fe := forge.NewFE()
-	b := builtins.Setup(fe)
-	fe.Exec(b.Lit, 4)
-	t.AssertEqual(fe.Pop(), 4)
-	// fe.Execute(forge.Code{b.Lit, 3, b.Lit, 2, b.Add})
-	// t.AssertEqual(fe.Pop(), 5)
+	b := builtins.Get(fe)
+	fe.Call(fe.Code(b.Lit, 4, b.Lit, 2, b.Add))
+	t.AssertEqual(fe.Pop(), 6)
 }