From 75b82db25064fdd6ac0ffadedf437238712f82f0 Mon Sep 17 00:00:00 2001
From: Helmut Merz <helmutm@cy55.de>
Date: Tue, 12 Sep 2023 11:59:51 +0200
Subject: [PATCH] forge, work in progress: factorial, using if, leave, repeat

---
 forge/builtins/builtins.go | 38 ++++++++++++++++++++++++--------------
 tests/forge_test.go        |  9 +++++++++
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/forge/builtins/builtins.go b/forge/builtins/builtins.go
index 308fb51..81e0242 100644
--- a/forge/builtins/builtins.go
+++ b/forge/builtins/builtins.go
@@ -9,8 +9,8 @@ type XT = forge.XT
 type FPtr = forge.FPtr
 
 type builtins struct {
-	Add, Body, Code, Comp, Drop, Dup, Get, If, IfElse, Leave, Lit, Mult,
-	New1, Put, Reg, Repeat, Swap,
+	Add, Body, Code, Comp, Drop, Dup, Get, If, IfElse, Leave, LT, Lit,
+	Mult, New1, Over, Put, Reg, Repeat, Sub, Swap,
 	Var1 XT
 }
 
@@ -29,30 +29,33 @@ func setup(f FE) *builtins {
 		return forge.Register(voc, forge.GoFunc(name, fct))
 	}
 	b := builtins{
-		Add: r("+", func(f FE, _ XT) { f.Push(f.PopI() + f.PopI()) }),
-		/*Append:  r("append", func(f FE, _ XT) {
-			item := f.Pop()
-			f.Peek(0).(FPtr).Append(item)
-		}),*/
+		Add:    r("+", func(f FE, _ XT) { f.Push(f.PopI() + f.PopI()) }),
 		Body:   r("body", func(f FE, _ XT) { f.Push(f.Pop().(XT).Code().New().Next()) }),
 		Code:   r("code", func(f FE, _ XT) { f.Push(f.Code()) }),
 		Comp:   r("comp", func(f FE, _ XT) { f.LatestXT().Code().Append(f.Pop()) }),
 		Drop:   r("drop", func(f FE, _ XT) { f.Pop() }),
 		Dup:    r("dup", func(f FE, _ XT) { f.Push(f.Peek(0)) }),
 		Get:    r("@", func(f FE, _ XT) { f.Push(f.Pop().(FPtr).Value()) }),
+		If:     r("if", func(f FE, _ XT) { doif(f) }),
+		IfElse: r("if-else", func(f FE, _ XT) { doifelse(f) }),
 		Leave:  r("leave", func(f FE, _ XT) { f.RPop() }),
 		Lit:    r("lit", func(f FE, _ XT) { f.Push(f.Literal()) }),
+		LT:     r("<", func(f FE, _ XT) { f.Push(f.PopI() > f.PopI()) }),
 		Mult:   r("*", func(f FE, _ XT) { f.Push(f.PopI() * f.PopI()) }),
 		New1:   r("new1", func(f FE, _ XT) { f.Push(f.NewVar()) }),
+		Over:   r("over", func(f FE, _ XT) { f.Push(f.Peek(1)) }),
 		Put:    r("!", func(f FE, _ XT) { f.Pop().(FPtr).Set(f.Pop()) }),
-		Reg:    r("reg", func(f FE, _ XT) { reg(f) }),
+		Reg:    r("reg", func(f FE, _ XT) { doreg(f) }),
 		Repeat: r("repeat", func(f FE, _ XT) { f.Reset() }),
-		Swap: r("swap", func(f FE, _ XT) {
-			a := f.Pop()
-			b := f.Pop()
-			f.Push(a)
-			f.Push(b)
+		Sub: r("-", func(f FE, _ XT) {
+			a := f.PopI()
+			f.Push(f.PopI() - a)
 		}),
+		Swap: r("swap", func(f FE, _ XT) { doswap(f) }),
+		/*Append:  r("append", func(f FE, _ XT) {
+			item := f.Pop()
+			f.Peek(0).(FPtr).Append(item)
+		}),*/
 	}
 	rf := func(name string, code ...forge.FItem) XT {
 		return forge.Register(voc, forge.FCode(name, f.Code(code...)))
@@ -78,7 +81,14 @@ func doifelse(f FE) {
 	}
 }
 
-func reg(f FE) {
+func doswap(f FE) {
+	a := f.Pop()
+	b := f.Pop()
+	f.Push(a)
+	f.Push(b)
+}
+
+func doreg(f FE) {
 	f.Register(forge.FCode(f.Pop().(string), f.Pop().(FPtr)))
 }
 
diff --git a/tests/forge_test.go b/tests/forge_test.go
index 65f6c91..fe316a9 100644
--- a/tests/forge_test.go
+++ b/tests/forge_test.go
@@ -21,6 +21,7 @@ func TestForge(tb *tbase.T) {
 	t := testing.SetUp(tb)
 	t.Run("exec", ExecTest)
 	t.Run("core", CoreTest)
+	t.Run("control", ControlTest)
 	t.Run("rep", RepTest)
 	t.Run("json", JsonTest)
 }
@@ -45,6 +46,14 @@ func CoreTest(t *testing.T) {
 }
 
 func ControlTest(t *testing.T) {
+	fac := fe.Exec(fe.Code(
+		b.Dup, fe.Code(
+			b.Dup, 3, b.LT, b.If, fe.Code(
+				b.Drop, b.Leave),
+			b.Swap, b.Over, b.Mult, b.Swap, 1, b.Sub, b.Repeat)),
+		"fac", b.Reg).LatestXT()
+	fe.Exec(2, fac)
+	//t.AssertEqual(fe.Pop(), 12)
 }
 
 func RepTest(t *testing.T) {