diff --git a/evaluator/evaluator.go b/evaluator/evaluator.go
index 33e65d2..96cd040 100644
--- a/evaluator/evaluator.go
+++ b/evaluator/evaluator.go
@@ -881,7 +881,7 @@ func evalObjectCallExpression(call *ast.ObjectCallExpression, env *object.Enviro
 		// `invokeMethod` interface on the object.
 		//
 		args := evalExpression(call.Call.(*ast.CallExpression).Arguments, env)
-		ret := obj.InvokeMethod(method.Function.String(), args...)
+		ret := obj.InvokeMethod(method.Function.String(), *env, args...)
 		if ret != nil {
 			return ret
 		}
diff --git a/object/environment.go b/object/environment.go
index bca6bf3..dadf6ec 100644
--- a/object/environment.go
+++ b/object/environment.go
@@ -3,6 +3,7 @@ package object
 import (
 	"fmt"
 	"os"
+	"strings"
 )
 
 // Environment stores our functions, variables, constants, etc.
@@ -28,6 +29,19 @@ func NewEnclosedEnvironment(outer *Environment) *Environment {
 	return env
 }
 
+// Names returns the names of every known-value with the
+// given prefix
+func (e *Environment) Names(prefix string) []string {
+	var ret []string
+
+	for key, _ := range e.store {
+		if strings.HasPrefix(key, prefix) {
+			ret = append(ret, key)
+		}
+	}
+	return ret
+}
+
 // Get returns the value of a given variable, by name.
 func (e *Environment) Get(name string) (Object, bool) {
 	obj, ok := e.store[name]
diff --git a/object/object.go b/object/object.go
index e2048aa..a823f62 100644
--- a/object/object.go
+++ b/object/object.go
@@ -36,7 +36,7 @@ type Object interface {
 
 	// InvokeMethod invokes a method against the object.
 	// (Built-in methods only.)
-	InvokeMethod(method string, args ...Object) Object
+	InvokeMethod(method string, env Environment, args ...Object) Object
 }
 
 // Hashable type can be hashed
diff --git a/object/object_array.go b/object/object_array.go
index 3ec0ce0..853fd89 100644
--- a/object/object_array.go
+++ b/object/object_array.go
@@ -2,6 +2,7 @@ package object
 
 import (
 	"bytes"
+	"sort"
 	"strings"
 )
 
@@ -44,12 +45,23 @@ func (ao *Array) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (ao *Array) InvokeMethod(method string, args ...Object) Object {
+func (ao *Array) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "len" {
 		return &Integer{Value: int64(len(ao.Elements))}
 	}
 	if method == "methods" {
-		names := []string{"len", "methods", "string"}
+		static := []string{"len", "methods", "string"}
+		dynamic := env.Names("array.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_bool.go b/object/object_bool.go
index d00f698..5840132 100644
--- a/object/object_bool.go
+++ b/object/object_bool.go
@@ -1,6 +1,10 @@
 package object
 
-import "fmt"
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
 
 // Boolean wraps bool and implements Object and Hashable interface.
 type Boolean struct {
@@ -44,9 +48,20 @@ func (b *Boolean) HashKey() HashKey {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (b *Boolean) InvokeMethod(method string, args ...Object) Object {
+func (b *Boolean) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "methods" {
-		names := []string{"methods", "string", "type"}
+		static := []string{"methods", "string", "type"}
+		dynamic := env.Names("bool.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_builtin.go b/object/object_builtin.go
index bbcb575..41e09b6 100644
--- a/object/object_builtin.go
+++ b/object/object_builtin.go
@@ -34,7 +34,7 @@ func (b *Builtin) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (b *Builtin) InvokeMethod(method string, args ...Object) Object {
+func (b *Builtin) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "methods" {
 		names := []string{"methods", "type"}
 
diff --git a/object/object_error.go b/object/object_error.go
index 4c60d83..69e709a 100644
--- a/object/object_error.go
+++ b/object/object_error.go
@@ -31,7 +31,7 @@ func (e *Error) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (e *Error) InvokeMethod(method string, args ...Object) Object {
+func (e *Error) InvokeMethod(method string, env Environment, args ...Object) Object {
 
 	//
 	// There are no methods available upon a return-object.
diff --git a/object/object_float.go b/object/object_float.go
index ea16415..028ec8d 100644
--- a/object/object_float.go
+++ b/object/object_float.go
@@ -2,7 +2,9 @@ package object
 
 import (
 	"hash/fnv"
+	"sort"
 	"strconv"
+	"strings"
 )
 
 // Float wraps float64 and implements Object and Hashable interfaces.
@@ -43,9 +45,20 @@ func (f *Float) HashKey() HashKey {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (f *Float) InvokeMethod(method string, args ...Object) Object {
+func (f *Float) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "methods" {
-		names := []string{"methods", "string", "type"}
+		static := []string{"methods", "string", "type"}
+		dynamic := env.Names("float.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_function.go b/object/object_function.go
index 6235645..183e0c5 100644
--- a/object/object_function.go
+++ b/object/object_function.go
@@ -2,6 +2,7 @@ package object
 
 import (
 	"bytes"
+	"sort"
 	"strings"
 
 	"github.com/skx/monkey/ast"
@@ -49,9 +50,20 @@ func (f *Function) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (f *Function) InvokeMethod(method string, args ...Object) Object {
+func (f *Function) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "methods" {
-		names := []string{"methods", "type"}
+		static := []string{"methods", "type"}
+		dynamic := env.Names("function.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_hash.go b/object/object_hash.go
index 1980af3..07525d3 100644
--- a/object/object_hash.go
+++ b/object/object_hash.go
@@ -3,6 +3,7 @@ package object
 import (
 	"bytes"
 	"fmt"
+	"sort"
 	"strings"
 )
 
@@ -64,9 +65,20 @@ func (h *Hash) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (h *Hash) InvokeMethod(method string, args ...Object) Object {
+func (h *Hash) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "methods" {
-		names := []string{"keys", "methods", "string", "type"}
+		static := []string{"keys", "methods", "string", "type"}
+		dynamic := env.Names("hash.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_int.go b/object/object_int.go
index da22045..728565a 100644
--- a/object/object_int.go
+++ b/object/object_int.go
@@ -1,6 +1,10 @@
 package object
 
-import "fmt"
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
 
 // Integer wraps int64 and implements Object and Hashable interfaces.
 type Integer struct {
@@ -38,12 +42,23 @@ func (i *Integer) HashKey() HashKey {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (i *Integer) InvokeMethod(method string, args ...Object) Object {
+func (i *Integer) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "chr" {
 		return &String{Value: string(i.Value)}
 	}
 	if method == "methods" {
-		names := []string{"chr", "methods", "string", "type"}
+		static := []string{"chr", "methods", "string", "type"}
+		dynamic := env.Names("integer.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {
diff --git a/object/object_null.go b/object/object_null.go
index 179fa20..561dbc9 100644
--- a/object/object_null.go
+++ b/object/object_null.go
@@ -26,6 +26,6 @@ func (n *Null) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (n *Null) InvokeMethod(method string, args ...Object) Object {
+func (n *Null) InvokeMethod(method string, env Environment, args ...Object) Object {
 	return nil
 }
diff --git a/object/object_return.go b/object/object_return.go
index 1859bb6..69eb33f 100644
--- a/object/object_return.go
+++ b/object/object_return.go
@@ -31,7 +31,7 @@ func (rv *ReturnValue) Inspect() string {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (rv *ReturnValue) InvokeMethod(method string, args ...Object) Object {
+func (rv *ReturnValue) InvokeMethod(method string, env Environment, args ...Object) Object {
 
 	//
 	// There are no methods available upon a return-object.
diff --git a/object/object_string.go b/object/object_string.go
index 8917101..d5bff52 100644
--- a/object/object_string.go
+++ b/object/object_string.go
@@ -4,6 +4,7 @@ package object
 
 import (
 	"hash/fnv"
+	"sort"
 	"strings"
 	"unicode/utf8"
 )
@@ -46,7 +47,7 @@ func (s *String) HashKey() HashKey {
 
 // InvokeMethod invokes a method against the object.
 // (Built-in methods only.)
-func (s *String) InvokeMethod(method string, args ...Object) Object {
+func (s *String) InvokeMethod(method string, env Environment, args ...Object) Object {
 	if method == "count" {
 		if len(args) < 1 {
 			return &Error{Message: "Missing argument to count()!"}
@@ -68,7 +69,18 @@ func (s *String) InvokeMethod(method string, args ...Object) Object {
 		return &Integer{Value: int64(utf8.RuneCountInString(s.Value))}
 	}
 	if method == "methods" {
-		names := []string{"count", "find", "len", "methods", "replace", "split", "type"}
+		static := []string{"count", "find", "len", "methods", "ord", "replace", "split", "type"}
+		dynamic := env.Names("string.")
+
+		var names []string
+		for _, e := range static {
+			names = append(names, e)
+		}
+		for _, e := range dynamic {
+			bits := strings.Split(e, ".")
+			names = append(names, bits[1])
+		}
+		sort.Strings(names)
 
 		result := make([]Object, len(names), len(names))
 		for i, txt := range names {