Fix issue with validation

Author: kenshaw

opts.go

@@ -1,6 +1,7 @@
 package ox
 
 import (
+	"cmp"
 	"context"
 	"fmt"
 	"io"
@@ -551,7 +552,7 @@ func Special(special string) FlagOption {
 }
 
 // Valid is a [Flag] option to add a allowed value validator to a flag.
-func Valid[T comparable](values ...T) FlagOption {
+func Valid[T cmp.Ordered](values ...T) FlagOption {
 	return option{
 		name: "Valid",
 		flag: func(g *Flag) error {

ox.go

@@ -441,13 +441,14 @@ func (ctx *Context) Populate(cmd *Command, all, overwrite bool) error {
 		case g.Type == HookT, g.Def == nil && !all:
 			continue
 		case g.Def != nil:
-			var err error
-			if value, err = ctx.Expand(g.Def); err != nil {
-				return err
+			v, err := ctx.Expand(g.Def)
+			if err != nil {
+				return fmt.Errorf("populate %s: cannot expand %v (%T): %w", g.Name, g.Def, g.Def, err)
 			}
+			value, _ = asString[string](v)
 		}
 		if err := ctx.Vars.Set(ctx, g, value, false); err != nil {
-			return fmt.Errorf("cannot populate %s with %q: %w", g.Name, value, err)
+			return fmt.Errorf("populate %s: %w", g.Name, err)
 		}
 	}
 	return nil
@@ -469,10 +470,10 @@ func (ctx *Context) Populate(cmd *Command, all, overwrite bool) error {
 //	$CONFIG_TYPE{KEY} - the registered config file loader type and key value, for example: `$YAML{my_key}`, `$TOML{my_key}`
 //
 // TODO: finish implementation for $CONFIG_TYPE, expand anywhere in string
-func (ctx *Context) Expand(v any) (string, error) {
+func (ctx *Context) Expand(v any) (any, error) {
 	s, ok := v.(string)
 	if !ok {
-		return asString[string](v)
+		return v, nil
 	}
 	if ctx.Override != nil {
 		if s, ok := ctx.Override[s]; ok {
@@ -524,7 +525,7 @@ func (ctx *Context) Expand(v any) (string, error) {
 	}
 	s, err := f()
 	if err != nil {
-		return "", fmt.Errorf("unable to expand %q: %w", s, err)
+		return "", fmt.Errorf("expand %q: %w", v, err)
 	}
 	return s, nil
 }

type.go

@@ -319,11 +319,15 @@ func typeRef(val any) Type {
 	case *url.URL:
 		return URLT
 	}
-	s := reflect.TypeOf(val).String()
-	if typ, ok := reflectTypes[s]; ok {
-		return typ
+	typ := reflect.TypeOf(val)
+	if typ != nil {
+		s := typ.String()
+		if typ, ok := reflectTypes[s]; ok {
+			return typ
+		}
+		return Type(s)
 	}
-	return Type(s)
+	return ""
 }
 
 // defaultType returns the type, map key type, and element type of v.

value.go

@@ -709,7 +709,7 @@ func invalid(val any) bool {
 }
 
 // valid creates a validator func for the provided values.
-func valid[T comparable](values ...T) func(any) error {
+func valid[T cmp.Ordered](values ...T) func(any) error {
 	return func(val any) error {
 		switch v, err := as[T](val, layout(val)); {
 		case err != nil: