From 0bb39f022fc70be8c041644d48918d571d359628 Mon Sep 17 00:00:00 2001
From: Helmut Merz <helmutm@cy55.de>
Date: Fri, 28 Jul 2023 09:45:51 +0200
Subject: [PATCH] forge: method Const() for storing and retrieving constant
 values

---
 forge/forge.go      | 18 +++++++++++-------
 tests/forge_test.go |  3 +++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/forge/forge.go b/forge/forge.go
index 0c955fb..44ebcaa 100644
--- a/forge/forge.go
+++ b/forge/forge.go
@@ -42,6 +42,7 @@ func newFE(voc *fvoc) *forgeEnv {
 
 var newVoc = voc.NewVoc[fitem]
 
+var newScalar = ptr.NewScalar[fitem]
 var newPtr = ptr.NewSlice[fitem]
 
 // xitem (executable item) / XT (execution token)
@@ -90,11 +91,18 @@ func (f *forgeEnv) Exec(items ...fitem) {
 }
 
 func (f *forgeEnv) Def(name string, items ...fitem) XT {
-	xt := Register(f.voc, name, callDef)
+	xt := Register(f.voc, name, doDef)
 	xt.body = newPtr(f.Code(items...)).Next()
 	return xt
 }
 
+func (f *forgeEnv) Const(name string, value fitem) XT {
+	xt := Register(f.voc, name, doData)
+	xt.body = newScalar()
+	xt.body.Append(value)
+	return xt
+}
+
 func (f *forgeEnv) Literal() {
 	f.Push(f.ip.Next().Value())
 }
@@ -115,16 +123,12 @@ func (f *forgeEnv) Peek(d int) fitem {
 	return f.ds.Peek(d)
 }
 
-func (f *forgeEnv) Const(name string) {
-}
-
 // basic functions for executable items
 
-func callDef(f *forgeEnv, xt XT) {
+func doDef(f *forgeEnv, xt XT) {
 	f.Call(xt.body.Value().(fptr))
 }
 
-func callData(f *forgeEnv, xt XT) {
+func doData(f *forgeEnv, xt XT) {
 	f.Push(xt.body.Value())
 }
-
diff --git a/tests/forge_test.go b/tests/forge_test.go
index c70d854..7a2023d 100644
--- a/tests/forge_test.go
+++ b/tests/forge_test.go
@@ -22,4 +22,7 @@ func ExecTest(t *testing.T) {
 	sq := fe.Def("square", b.Dup, b.Mult)
 	fe.Exec(b.Lit, 3, sq, b.Lit, 2, b.Add)
 	t.AssertEqual(fe.Pop(), 11)
+	seven := fe.Const("seven", 7)
+	fe.Exec(b.Lit, 3, seven, sq, b.Add)
+	t.AssertEqual(fe.Pop(), 52)
 }