Added all source files

term-constuctor-registry.go

@@ -0,0 +1,25 @@
+// op-registry.go
+package expr
+
+const initialRegistryCapacity = 10
+
+type termContructor func(tk *Token) *term
+
+var constructorRegistry map[Symbol]termContructor = nil
+
+func registerTermConstructor(sym Symbol, constructor termContructor) {
+	if constructorRegistry == nil {
+		constructorRegistry = make(map[Symbol]termContructor, initialRegistryCapacity)
+	}
+	constructorRegistry[sym] = constructor
+}
+
+func newTerm(tk *Token, parent *term) (inst *term) {
+	if constructorRegistry != nil {
+		if construct, exists := constructorRegistry[tk.Sym]; exists {
+			inst = construct(tk)
+			inst.setParent(parent)
+		}
+	}
+	return
+}