adding Unwrap on all object types so we can also add sprintf and pass…

… the variadic any args to it

eval/eval_test.go

@@ -770,4 +770,14 @@ func TestExtension(t *testing.T) {
 	input = `round(2.7)`
 	evaluated = testEval(t, input)
 	testFloatObject(t, evaluated, 3)
+	input = `sprintf("%d %s %g", 42, "ab\ncd", pow(2, 43))`
+	evaluated = testEval(t, input)
+	expected = "42 ab\ncd 8.796093022208e+12" // might be brittle the %g output of float64.
+	actual, ok := evaluated.(object.String)
+	if !ok {
+		t.Errorf("object is not string. got=%T (%+v)", evaluated, evaluated)
+	}
+	if actual.Value != expected {
+		t.Errorf("object has wrong value. got=%q, want=%q", actual, expected)
+	}
 }

extensions/extension.go

@@ -3,6 +3,7 @@
 package extensions
 
 import (
+	"fmt"
 	"math"
 
 	"grol.io/grol/object"
@@ -36,6 +37,16 @@ func initInternal() error {
 	if err != nil {
 		return err
 	}
+	err = object.CreateFunction(object.Extension{
+		Name:     "sprintf",
+		MinArgs:  1,
+		MaxArgs:  -1,
+		ArgTypes: []object.Type{object.STRING},
+		Callback: sprintf,
+	})
+	if err != nil {
+		return err
+	}
 	oneFloat := object.Extension{
 		MinArgs:  1,
 		MaxArgs:  1,
@@ -79,3 +90,8 @@ func pow(args []object.Object) object.Object {
 	result := math.Pow(base, exp)
 	return object.Float{Value: result}
 }
+
+func sprintf(args []object.Object) object.Object {
+	res := fmt.Sprintf(args[0].(object.String).Value, object.Unwrap(args[1:])...)
+	return object.String{Value: res}
+}

object/interp.go

@@ -36,3 +36,11 @@ func CreateFunction(cmd Extension) error {
 func ExtraFunctions() map[string]Extension {
 	return extraFunctions
 }
+
+func Unwrap(objs []Object) []any {
+	res := make([]any, len(objs))
+	for i, o := range objs {
+		res[i] = o.Unwrap()
+	}
+	return res
+}

object/object.go

@@ -15,6 +15,7 @@ type Type uint8
 type Object interface {
 	Type() Type
 	Inspect() string
+	Unwrap() any
 }
 
 const (
@@ -120,6 +121,10 @@ func (i Integer) Inspect() string {
 	return strconv.FormatInt(i.Value, 10)
 }
 
+func (i Integer) Unwrap() any {
+	return i.Value
+}
+
 func (i Integer) Type() Type {
 	return INTEGER
 }
@@ -128,6 +133,10 @@ type Float struct {
 	Value float64
 }
 
+func (f Float) Unwrap() any {
+	return f.Value
+}
+
 func (f Float) Type() Type {
 	return FLOAT
 }
@@ -140,6 +149,10 @@ type Boolean struct {
 	Value bool
 }
 
+func (b Boolean) Unwrap() any {
+	return b.Value
+}
+
 func (b Boolean) Type() Type {
 	return BOOLEAN
 }
@@ -152,6 +165,10 @@ type String struct {
 	Value string
 }
 
+func (s String) Unwrap() any {
+	return s.Value
+}
+
 func (s String) Type() Type {
 	return STRING
 }
@@ -162,20 +179,24 @@ func (s String) Inspect() string {
 
 type Null struct{}
 
+func (n Null) Unwrap() any     { return nil }
 func (n Null) Type() Type      { return NIL }
 func (n Null) Inspect() string { return "nil" }
 
 type Error struct {
 	Value string // message
 }
 
+func (e Error) Unwrap() any     { return e }
+func (e Error) Error() string   { return e.Value }
 func (e Error) Type() Type      { return ERROR }
 func (e Error) Inspect() string { return "<err: " + e.Value + ">" }
 
 type ReturnValue struct {
 	Value Object
 }
 
+func (rv ReturnValue) Unwrap() any     { return rv.Value }
 func (rv ReturnValue) Type() Type      { return RETURN }
 func (rv ReturnValue) Inspect() string { return rv.Value.Inspect() }
 
@@ -198,7 +219,8 @@ func WriteStrings(out *strings.Builder, list []Object, before, sep, after string
 	out.WriteString(after)
 }
 
-func (f Function) Type() Type { return FUNC }
+func (f Function) Unwrap() any { return f }
+func (f Function) Type() Type  { return FUNC }
 
 // Must be called after the function is fully initialized.
 // Whether a function result should be cached doesn't depend on the Name,
@@ -235,7 +257,8 @@ type Array struct {
 	Elements []Object
 }
 
-func (ao Array) Type() Type { return ARRAY }
+func (ao Array) Unwrap() any { return Unwrap(ao.Elements) }
+func (ao Array) Type() Type  { return ARRAY }
 func (ao Array) Inspect() string {
 	out := strings.Builder{}
 	WriteStrings(&out, ao.Elements, "[", ",", "]")
@@ -290,6 +313,14 @@ func (mk MapKeys) Swap(i, j int) {
 	mk[i], mk[j] = mk[j], mk[i]
 }
 
+func (m Map) Unwrap() any {
+	res := make(map[any]any, len(m))
+	for k, v := range m {
+		res[k.Unwrap()] = v.Unwrap()
+	}
+	return res
+}
+
 func (m Map) Type() Type { return MAP }
 
 func (m Map) Inspect() string {
@@ -318,7 +349,8 @@ type Quote struct {
 	Node ast.Node
 }
 
-func (q Quote) Type() Type { return QUOTE }
+func (q Quote) Unwrap() any { return q.Node }
+func (q Quote) Type() Type  { return QUOTE }
 func (q Quote) Inspect() string {
 	out := strings.Builder{}
 	out.WriteString("quote(")
@@ -333,7 +365,8 @@ type Macro struct {
 	Env        *Environment
 }
 
-func (m Macro) Type() Type { return MACRO }
+func (m Macro) Unwrap() any { return m }
+func (m Macro) Type() Type  { return MACRO }
 func (m Macro) Inspect() string {
 	out := strings.Builder{}
 	out.WriteString("macro(")
@@ -374,7 +407,8 @@ func (e *Extension) Usage(out *strings.Builder) {
 	}
 }
 
-func (e Extension) Type() Type { return EXTENSION }
+func (e Extension) Unwrap() any { return e }
+func (e Extension) Type() Type  { return EXTENSION }
 func (e Extension) Inspect() string {
 	out := strings.Builder{}
 	out.WriteString(e.Name)