diff --git a/lang/funcs/contains_polyfunc.go b/lang/funcs/contains_polyfunc.go
index 916ca657..3b9fe46c 100644
--- a/lang/funcs/contains_polyfunc.go
+++ b/lang/funcs/contains_polyfunc.go
@@ -48,6 +48,12 @@ type ContainsPolyFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ContainsPolyFunc) String() string {
+	return ContainsFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *ContainsPolyFunc) ArgGen(index int) (string, error) {
 	seq := []string{"needle", "haystack"}
diff --git a/lang/funcs/core/datetime/now_fact.go b/lang/funcs/core/datetime/now_fact.go
index 055b4cc4..be5bacc4 100644
--- a/lang/funcs/core/datetime/now_fact.go
+++ b/lang/funcs/core/datetime/now_fact.go
@@ -24,8 +24,14 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// NowFuncName is the name this fact is registered as. It's still a Func
+	// Name because this is the name space the fact is actually using.
+	NowFuncName = "now"
+)
+
 func init() {
-	facts.ModuleRegister(ModuleName, "now", func() facts.Fact { return &DateTimeFact{} }) // must register the fact and name
+	facts.ModuleRegister(ModuleName, NowFuncName, func() facts.Fact { return &DateTimeFact{} }) // must register the fact and name
 }
 
 // DateTimeFact is a fact which returns the current date and time.
@@ -34,6 +40,12 @@ type DateTimeFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *DateTimeFact) String() string {
+	return NowFuncName
+}
+
 // Validate makes sure we've built our struct properly. It is usually unused for
 // normal facts that users can use directly.
 //func (obj *DateTimeFact) Validate() error {
diff --git a/lang/funcs/core/deploy/abspath_func.go b/lang/funcs/core/deploy/abspath_func.go
index 0fdf2054..af22c956 100644
--- a/lang/funcs/core/deploy/abspath_func.go
+++ b/lang/funcs/core/deploy/abspath_func.go
@@ -26,14 +26,17 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// AbsPathFuncName is the name this function is registered as.
+	AbsPathFuncName = "abspath"
+
+	pathArg = "path"
+)
+
 func init() {
 	funcs.ModuleRegister(ModuleName, "abspath", func() interfaces.Func { return &AbsPathFunc{} }) // must register the func and name
 }
 
-const (
-	pathArg = "path"
-)
-
 // AbsPathFunc is a function that returns the absolute, full path in the deploy
 // from an input path that is relative to the calling file. If you pass it an
 // empty string, you'll just get the absolute deploy directory path that you're
@@ -49,6 +52,12 @@ type AbsPathFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *AbsPathFunc) String() string {
+	return AbsPathFuncName
+}
+
 // SetData is used by the language to pass our function some code-level context.
 func (obj *AbsPathFunc) SetData(data *interfaces.FuncData) {
 	obj.data = data
diff --git a/lang/funcs/core/deploy/readfile_func.go b/lang/funcs/core/deploy/readfile_func.go
index b3e74ed9..176d6ebe 100644
--- a/lang/funcs/core/deploy/readfile_func.go
+++ b/lang/funcs/core/deploy/readfile_func.go
@@ -27,8 +27,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// ReadFileFuncName is the name this function is registered as.
+	ReadFileFuncName = "readfile"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "readfile", func() interfaces.Func { return &ReadFileFunc{} }) // must register the func and name
+	funcs.ModuleRegister(ModuleName, ReadFileFuncName, func() interfaces.Func { return &ReadFileFunc{} }) // must register the func and name
 }
 
 // ReadFileFunc is a function that reads the full contents from a file in our
@@ -46,6 +51,12 @@ type ReadFileFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ReadFileFunc) String() string {
+	return ReadFileFuncName
+}
+
 // SetData is used by the language to pass our function some code-level context.
 func (obj *ReadFileFunc) SetData(data *interfaces.FuncData) {
 	obj.data = data
diff --git a/lang/funcs/core/deploy/readfileabs_func.go b/lang/funcs/core/deploy/readfileabs_func.go
index 2e6d93ac..0f9fb748 100644
--- a/lang/funcs/core/deploy/readfileabs_func.go
+++ b/lang/funcs/core/deploy/readfileabs_func.go
@@ -26,8 +26,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// ReadFileAbsFuncName is the name this function is registered as.
+	ReadFileAbsFuncName = "readfileabs"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "readfileabs", func() interfaces.Func { return &ReadFileAbsFunc{} }) // must register the func and name
+	funcs.ModuleRegister(ModuleName, ReadFileAbsFuncName, func() interfaces.Func { return &ReadFileAbsFunc{} }) // must register the func and name
 }
 
 // ReadFileAbsFunc is a function that reads the full contents from a file in our
@@ -46,6 +51,12 @@ type ReadFileAbsFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ReadFileAbsFunc) String() string {
+	return ReadFileAbsFuncName
+}
+
 // SetData is used by the language to pass our function some code-level context.
 func (obj *ReadFileAbsFunc) SetData(data *interfaces.FuncData) {
 	obj.data = data
diff --git a/lang/funcs/core/example/flipflop_fact.go b/lang/funcs/core/example/flipflop_fact.go
index cdd38bfa..45a320f5 100644
--- a/lang/funcs/core/example/flipflop_fact.go
+++ b/lang/funcs/core/example/flipflop_fact.go
@@ -24,8 +24,14 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// FlipFlopFuncName is the name this fact is registered as. It's still a
+	// Func Name because this is the name space the fact is actually using.
+	FlipFlopFuncName = "flipflop"
+)
+
 func init() {
-	facts.ModuleRegister(ModuleName, "flipflop", func() facts.Fact { return &FlipFlopFact{} }) // must register the fact and name
+	facts.ModuleRegister(ModuleName, FlipFlopFuncName, func() facts.Fact { return &FlipFlopFact{} }) // must register the fact and name
 }
 
 // FlipFlopFact is a fact which flips a bool repeatedly. This is an example fact
@@ -37,6 +43,12 @@ type FlipFlopFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *FlipFlopFact) String() string {
+	return FlipFlopFuncName
+}
+
 // Validate makes sure we've built our struct properly. It is usually unused for
 // normal facts that users can use directly.
 //func (obj *FlipFlopFact) Validate() error {
diff --git a/lang/funcs/core/example/vumeter_func.go b/lang/funcs/core/example/vumeter_func.go
index c4bdff95..55142fa7 100644
--- a/lang/funcs/core/example/vumeter_func.go
+++ b/lang/funcs/core/example/vumeter_func.go
@@ -35,8 +35,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// VUMeterFuncName is the name this function is registered as.
+	VUMeterFuncName = "vumeter"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "vumeter", func() interfaces.Func { return &VUMeterFunc{} }) // must register the func and name
+	funcs.ModuleRegister(ModuleName, VUMeterFuncName, func() interfaces.Func { return &VUMeterFunc{} }) // must register the func and name
 }
 
 // VUMeterFunc is a gimmic function to display a vu meter from the microphone.
@@ -53,6 +58,12 @@ type VUMeterFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *VUMeterFunc) String() string {
+	return VUMeterFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *VUMeterFunc) ArgGen(index int) (string, error) {
 	seq := []string{"symbol", "multiplier", "peak"}
diff --git a/lang/funcs/core/fmt/printf_func.go b/lang/funcs/core/fmt/printf_func.go
index f8f34a68..7d9f06e8 100644
--- a/lang/funcs/core/fmt/printf_func.go
+++ b/lang/funcs/core/fmt/printf_func.go
@@ -27,15 +27,18 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
-func init() {
-	// FIXME: should this be named sprintf instead?
-	funcs.ModuleRegister(ModuleName, "printf", func() interfaces.Func { return &PrintfFunc{} })
-}
-
 const (
+	// PrintfFuncName is the name this function is registered as.
+	// FIXME: should this be named sprintf instead?
+	PrintfFuncName = "printf"
+
 	formatArgName = "format" // name of the first arg
 )
 
+func init() {
+	funcs.ModuleRegister(ModuleName, PrintfFuncName, func() interfaces.Func { return &PrintfFunc{} })
+}
+
 // PrintfFunc is a static polymorphic function that compiles a format string and
 // returns the output as a string. It bases its output on the values passed in
 // to it. It examines the type of the arguments at compile time and then
@@ -56,6 +59,12 @@ type PrintfFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *PrintfFunc) String() string {
+	return PrintfFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *PrintfFunc) ArgGen(index int) (string, error) {
 	if index == 0 {
diff --git a/lang/funcs/core/iter/map_func.go b/lang/funcs/core/iter/map_func.go
index 3abba2f3..970ec526 100644
--- a/lang/funcs/core/iter/map_func.go
+++ b/lang/funcs/core/iter/map_func.go
@@ -27,9 +27,14 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
-func init() {
+const (
+	// MapFuncName is the name this function is registered as.
 	// XXX: rename to map once our parser sees a function name and not a type
-	funcs.ModuleRegister(ModuleName, "xmap", func() interfaces.Func { return &MapFunc{} }) // must register the func and name
+	MapFuncName = "xmap"
+)
+
+func init() {
+	funcs.ModuleRegister(ModuleName, MapFuncName, func() interfaces.Func { return &MapFunc{} }) // must register the func and name
 }
 
 const (
@@ -62,6 +67,12 @@ type MapFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *MapFunc) String() string {
+	return MapFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *MapFunc) ArgGen(index int) (string, error) {
 	seq := []string{argNameInputs, argNameFunction} // inverted for pretty!
diff --git a/lang/funcs/core/os/readfile_func.go b/lang/funcs/core/os/readfile_func.go
index 66394388..48201886 100644
--- a/lang/funcs/core/os/readfile_func.go
+++ b/lang/funcs/core/os/readfile_func.go
@@ -29,8 +29,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// ReadFileFuncName is the name this function is registered as.
+	ReadFileFuncName = "readfile"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "readfile", func() interfaces.Func { return &ReadFileFunc{} }) // must register the func and name
+	funcs.ModuleRegister(ModuleName, ReadFileFuncName, func() interfaces.Func { return &ReadFileFunc{} }) // must register the func and name
 }
 
 // ReadFileFunc is a function that reads the full contents from a local file. If
@@ -51,6 +56,12 @@ type ReadFileFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ReadFileFunc) String() string {
+	return ReadFileFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *ReadFileFunc) ArgGen(index int) (string, error) {
 	seq := []string{"filename"}
diff --git a/lang/funcs/core/os/system_func.go b/lang/funcs/core/os/system_func.go
index e7cfd5c3..ceb8bdf8 100644
--- a/lang/funcs/core/os/system_func.go
+++ b/lang/funcs/core/os/system_func.go
@@ -29,8 +29,13 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// SystemFuncName is the name this function is registered as.
+	SystemFuncName = "system"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "system", func() interfaces.Func { return &SystemFunc{} })
+	funcs.ModuleRegister(ModuleName, SystemFuncName, func() interfaces.Func { return &SystemFunc{} })
 }
 
 // SystemFunc runs a string as a shell command, then produces each line from
@@ -47,6 +52,12 @@ type SystemFunc struct {
 	cancel    context.CancelFunc
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *SystemFunc) String() string {
+	return SystemFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *SystemFunc) ArgGen(index int) (string, error) {
 	seq := []string{"shell_command"}
diff --git a/lang/funcs/core/random1_func.go b/lang/funcs/core/random1_func.go
index 02205aa6..9cd8cd9c 100644
--- a/lang/funcs/core/random1_func.go
+++ b/lang/funcs/core/random1_func.go
@@ -28,10 +28,15 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
-const alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+const (
+	// Random1FuncName is the name this function is registered as.
+	Random1FuncName = "random1"
+
+	alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+)
 
 func init() {
-	funcs.Register("random1", func() interfaces.Func { return &Random1Func{} })
+	funcs.Register(Random1FuncName, func() interfaces.Func { return &Random1Func{} })
 }
 
 // Random1Func returns one random string of a certain length.
@@ -52,6 +57,12 @@ type Random1Func struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *Random1Func) String() string {
+	return Random1FuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *Random1Func) ArgGen(index int) (string, error) {
 	seq := []string{"length"}
diff --git a/lang/funcs/core/sys/cpucount_fact.go b/lang/funcs/core/sys/cpucount_fact.go
index e4b7ef13..af3d60a0 100644
--- a/lang/funcs/core/sys/cpucount_fact.go
+++ b/lang/funcs/core/sys/cpucount_fact.go
@@ -35,13 +35,17 @@ import (
 )
 
 const (
+	// CPUCountFuncName is the name this fact is registered as. It's still a
+	// Func Name because this is the name space the fact is actually using.
+	CPUCountFuncName = "cpu_count"
+
 	rtmGrps         = 0x1 // make me a multicast receiver
 	socketFile      = "pipe.sock"
 	cpuDevpathRegex = "/devices/system/cpu/cpu[0-9]"
 )
 
 func init() {
-	facts.ModuleRegister(ModuleName, "cpu_count", func() facts.Fact { return &CPUCountFact{} }) // must register the fact and name
+	facts.ModuleRegister(ModuleName, CPUCountFuncName, func() facts.Fact { return &CPUCountFact{} }) // must register the fact and name
 }
 
 // CPUCountFact is a fact that returns the current CPU count.
@@ -50,6 +54,12 @@ type CPUCountFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *CPUCountFact) String() string {
+	return CPUCountFuncName
+}
+
 // Info returns static typing info about what the fact returns.
 func (obj *CPUCountFact) Info() *facts.Info {
 	return &facts.Info{
diff --git a/lang/funcs/core/sys/hostname_fact.go b/lang/funcs/core/sys/hostname_fact.go
index a6899429..ee9bbf97 100644
--- a/lang/funcs/core/sys/hostname_fact.go
+++ b/lang/funcs/core/sys/hostname_fact.go
@@ -22,8 +22,14 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// HostnameFuncName is the name this fact is registered as. It's still a
+	// Func Name because this is the name space the fact is actually using.
+	HostnameFuncName = "hostname"
+)
+
 func init() {
-	facts.ModuleRegister(ModuleName, "hostname", func() facts.Fact { return &HostnameFact{} }) // must register the fact and name
+	facts.ModuleRegister(ModuleName, HostnameFuncName, func() facts.Fact { return &HostnameFact{} }) // must register the fact and name
 }
 
 // HostnameFact is a function that returns the hostname.
@@ -33,6 +39,12 @@ type HostnameFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *HostnameFact) String() string {
+	return HostnameFuncName
+}
+
 // Validate makes sure we've built our struct properly. It is usually unused for
 // normal facts that users can use directly.
 //func (obj *HostnameFact) Validate() error {
diff --git a/lang/funcs/core/sys/load_fact.go b/lang/funcs/core/sys/load_fact.go
index 6b8e5dc9..5ea49370 100644
--- a/lang/funcs/core/sys/load_fact.go
+++ b/lang/funcs/core/sys/load_fact.go
@@ -26,11 +26,15 @@ import (
 )
 
 const (
+	// LoadFuncName is the name this fact is registered as. It's still a
+	// Func Name because this is the name space the fact is actually using.
+	LoadFuncName = "load"
+
 	loadSignature = "struct{x1 float; x5 float; x15 float}"
 )
 
 func init() {
-	facts.ModuleRegister(ModuleName, "load", func() facts.Fact { return &LoadFact{} }) // must register the fact and name
+	facts.ModuleRegister(ModuleName, LoadFuncName, func() facts.Fact { return &LoadFact{} }) // must register the fact and name
 }
 
 // LoadFact is a fact which returns the current system load.
@@ -39,6 +43,12 @@ type LoadFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *LoadFact) String() string {
+	return LoadFuncName
+}
+
 // Validate makes sure we've built our struct properly. It is usually unused for
 // normal facts that users can use directly.
 //func (obj *LoadFact) Validate() error {
diff --git a/lang/funcs/core/sys/uptime_fact.go b/lang/funcs/core/sys/uptime_fact.go
index bfe17290..b3694b74 100644
--- a/lang/funcs/core/sys/uptime_fact.go
+++ b/lang/funcs/core/sys/uptime_fact.go
@@ -25,8 +25,14 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// UptimeFuncName is the name this fact is registered as. It's still a
+	// Func Name because this is the name space the fact is actually using.
+	UptimeFuncName = "uptime"
+)
+
 func init() {
-	facts.ModuleRegister(ModuleName, "uptime", func() facts.Fact { return &UptimeFact{} })
+	facts.ModuleRegister(ModuleName, UptimeFuncName, func() facts.Fact { return &UptimeFact{} })
 }
 
 // UptimeFact is a fact which returns the current uptime of your system.
@@ -35,6 +41,12 @@ type UptimeFact struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this fact. This is needed so this struct can
+// satisfy the pgraph.Vertex interface.
+func (obj *UptimeFact) String() string {
+	return UptimeFuncName
+}
+
 // Info returns some static info about itself.
 func (obj *UptimeFact) Info() *facts.Info {
 	return &facts.Info{
diff --git a/lang/funcs/core/template_func.go b/lang/funcs/core/template_func.go
index 2b0622c2..f3b52bb6 100644
--- a/lang/funcs/core/template_func.go
+++ b/lang/funcs/core/template_func.go
@@ -31,17 +31,10 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
-var (
-	// errorType represents a reflection type of error as seen in:
-	// https://github.com/golang/go/blob/ec62ee7f6d3839fe69aeae538dadc1c9dc3bf020/src/text/template/exec.go#L612
-	errorType = reflect.TypeOf((*error)(nil)).Elem()
-)
-
-func init() {
-	funcs.Register("template", func() interfaces.Func { return &TemplateFunc{} })
-}
-
 const (
+	// TemplateFuncName is the name this function is registered as.
+	TemplateFuncName = "template"
+
 	// TemplateName is the name of our template as required by the template
 	// library.
 	TemplateName = "template"
@@ -50,6 +43,16 @@ const (
 	argNameVars     = "vars"
 )
 
+var (
+	// errorType represents a reflection type of error as seen in:
+	// https://github.com/golang/go/blob/ec62ee7f6d3839fe69aeae538dadc1c9dc3bf020/src/text/template/exec.go#L612
+	errorType = reflect.TypeOf((*error)(nil)).Elem()
+)
+
+func init() {
+	funcs.Register(TemplateFuncName, func() interfaces.Func { return &TemplateFunc{} })
+}
+
 // TemplateFunc is a static polymorphic function that compiles a template and
 // returns the output as a string. It bases its output on the values passed in
 // to it. It examines the type of the second argument (the input data vars) at
@@ -73,6 +76,12 @@ type TemplateFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *TemplateFunc) String() string {
+	return TemplateFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *TemplateFunc) ArgGen(index int) (string, error) {
 	seq := []string{argNameTemplate, argNameVars}
diff --git a/lang/funcs/core/world/exchange_func.go b/lang/funcs/core/world/exchange_func.go
index 92c7fc39..f7e3375c 100644
--- a/lang/funcs/core/world/exchange_func.go
+++ b/lang/funcs/core/world/exchange_func.go
@@ -27,8 +27,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// ExchangeFuncName is the name this function is registered as.
+	ExchangeFuncName = "exchange"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "exchange", func() interfaces.Func { return &ExchangeFunc{} })
+	funcs.ModuleRegister(ModuleName, ExchangeFuncName, func() interfaces.Func { return &ExchangeFunc{} })
 }
 
 // ExchangeFunc is special function which returns all the values of a given key
@@ -46,6 +51,12 @@ type ExchangeFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ExchangeFunc) String() string {
+	return ExchangeFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *ExchangeFunc) ArgGen(index int) (string, error) {
 	seq := []string{"namespace", "value"}
diff --git a/lang/funcs/core/world/kvlookup_func.go b/lang/funcs/core/world/kvlookup_func.go
index ff288c6c..2ce7b143 100644
--- a/lang/funcs/core/world/kvlookup_func.go
+++ b/lang/funcs/core/world/kvlookup_func.go
@@ -27,8 +27,13 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// KVLookupFuncName is the name this function is registered as.
+	KVLookupFuncName = "kvlookup"
+)
+
 func init() {
-	funcs.ModuleRegister(ModuleName, "kvlookup", func() interfaces.Func { return &KVLookupFunc{} })
+	funcs.ModuleRegister(ModuleName, KVLookupFuncName, func() interfaces.Func { return &KVLookupFunc{} })
 }
 
 // KVLookupFunc is special function which returns all the values of a given key
@@ -46,6 +51,12 @@ type KVLookupFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *KVLookupFunc) String() string {
+	return KVLookupFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *KVLookupFunc) ArgGen(index int) (string, error) {
 	seq := []string{"namespace"}
diff --git a/lang/funcs/core/world/schedule_func.go b/lang/funcs/core/world/schedule_func.go
index 2ff8f06f..f39b67dc 100644
--- a/lang/funcs/core/world/schedule_func.go
+++ b/lang/funcs/core/world/schedule_func.go
@@ -42,6 +42,9 @@ import (
 )
 
 const (
+	// ScheduleFuncName is the name this function is registered as.
+	ScheduleFuncName = "schedule"
+
 	// DefaultStrategy is the strategy to use if none has been specified.
 	DefaultStrategy = "rr"
 
@@ -58,7 +61,7 @@ const (
 )
 
 func init() {
-	funcs.ModuleRegister(ModuleName, "schedule", func() interfaces.Func { return &SchedulePolyFunc{} })
+	funcs.ModuleRegister(ModuleName, ScheduleFuncName, func() interfaces.Func { return &SchedulePolyFunc{} })
 }
 
 // SchedulePolyFunc is special function which determines where code should run
@@ -80,6 +83,12 @@ type SchedulePolyFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *SchedulePolyFunc) String() string {
+	return ScheduleFuncName
+}
+
 // validOpts returns the available mapping of valid opts fields to types.
 func (obj *SchedulePolyFunc) validOpts() map[string]*types.Type {
 	return map[string]*types.Type{
diff --git a/lang/funcs/facts/facts.go b/lang/funcs/facts/facts.go
index 417939ad..78f3e2ef 100644
--- a/lang/funcs/facts/facts.go
+++ b/lang/funcs/facts/facts.go
@@ -79,6 +79,7 @@ type Init struct {
 // never change to avoid the overhead of the goroutine and channel listener?
 // TODO: should we move this to the interface package?
 type Fact interface {
+	String() string
 	//Validate() error // currently not needed since no facts are internal
 	Info() *Info
 	Init(*Init) error
diff --git a/lang/funcs/facts/func.go b/lang/funcs/facts/func.go
index 9adad7c7..4601dfdd 100644
--- a/lang/funcs/facts/func.go
+++ b/lang/funcs/facts/func.go
@@ -30,6 +30,12 @@ type FactFunc struct { // implements `interfaces.Func`
 	Fact Fact
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *FactFunc) String() string {
+	return obj.Fact.String()
+}
+
 // Validate makes sure we've built our struct properly.
 func (obj *FactFunc) Validate() error {
 	if obj.Fact == nil {
diff --git a/lang/funcs/history_polyfunc.go b/lang/funcs/history_polyfunc.go
index dcaa5ae4..7bfb87e8 100644
--- a/lang/funcs/history_polyfunc.go
+++ b/lang/funcs/history_polyfunc.go
@@ -58,6 +58,12 @@ type HistoryFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *HistoryFunc) String() string {
+	return HistoryFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *HistoryFunc) ArgGen(index int) (string, error) {
 	seq := []string{"value", "index"}
diff --git a/lang/funcs/maplookup_polyfunc.go b/lang/funcs/maplookup_polyfunc.go
index 89436353..8d1c1cd8 100644
--- a/lang/funcs/maplookup_polyfunc.go
+++ b/lang/funcs/maplookup_polyfunc.go
@@ -52,6 +52,12 @@ type MapLookupPolyFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *MapLookupPolyFunc) String() string {
+	return MapLookupFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *MapLookupPolyFunc) ArgGen(index int) (string, error) {
 	seq := []string{argNameMap, argNameKey, argNameDef}
diff --git a/lang/funcs/operator_polyfunc.go b/lang/funcs/operator_polyfunc.go
index f82430a7..741d85ed 100644
--- a/lang/funcs/operator_polyfunc.go
+++ b/lang/funcs/operator_polyfunc.go
@@ -435,6 +435,13 @@ type OperatorPolyFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *OperatorPolyFunc) String() string {
+	// TODO: return the exact operator if we can guarantee it doesn't change
+	return OperatorFuncName
+}
+
 // argNames returns the maximum list of possible argNames. This can be truncated
 // if needed. The first arg name is the operator.
 func (obj *OperatorPolyFunc) argNames() ([]string, error) {
diff --git a/lang/funcs/simple/simple.go b/lang/funcs/simple/simple.go
index d84d8ad9..880d2ba0 100644
--- a/lang/funcs/simple/simple.go
+++ b/lang/funcs/simple/simple.go
@@ -58,7 +58,7 @@ func Register(name string, fn *types.FuncValue) {
 	RegisteredFuncs[name] = fn // store a copy for ourselves
 
 	// register a copy in the main function database
-	funcs.Register(name, func() interfaces.Func { return &WrappedFunc{Fn: fn} })
+	funcs.Register(name, func() interfaces.Func { return &WrappedFunc{Name: name, Fn: fn} })
 }
 
 // ModuleRegister is exactly like Register, except that it registers within a
@@ -70,6 +70,8 @@ func ModuleRegister(module, name string, fn *types.FuncValue) {
 // WrappedFunc is a scaffolding function struct which fulfills the boiler-plate
 // for the function API, but that can run a very simple, static, pure function.
 type WrappedFunc struct {
+	Name string
+
 	Fn *types.FuncValue
 
 	init *interfaces.Init
@@ -80,6 +82,12 @@ type WrappedFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *WrappedFunc) String() string {
+	return obj.Name
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *WrappedFunc) ArgGen(index int) (string, error) {
 	typ := obj.Fn.Type()
diff --git a/lang/funcs/simplepoly/simplepoly.go b/lang/funcs/simplepoly/simplepoly.go
index 30c498e7..6ab85114 100644
--- a/lang/funcs/simplepoly/simplepoly.go
+++ b/lang/funcs/simplepoly/simplepoly.go
@@ -90,7 +90,7 @@ func Register(name string, fns []*types.FuncValue) {
 	RegisteredFuncs[name] = fns // store a copy for ourselves
 
 	// register a copy in the main function database
-	funcs.Register(name, func() interfaces.Func { return &WrappedFunc{Fns: fns} })
+	funcs.Register(name, func() interfaces.Func { return &WrappedFunc{Name: name, Fns: fns} })
 }
 
 // ModuleRegister is exactly like Register, except that it registers within a
@@ -131,6 +131,8 @@ func consistentArgs(fns []*types.FuncValue) ([]string, error) {
 // for the function API, but that can run a very simple, static, pure,
 // polymorphic function.
 type WrappedFunc struct {
+	Name string
+
 	Fns []*types.FuncValue // list of possible functions
 
 	fn *types.FuncValue // the concrete version of our chosen function
@@ -143,6 +145,12 @@ type WrappedFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *WrappedFunc) String() string {
+	return obj.Name
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *WrappedFunc) ArgGen(index int) (string, error) {
 	seq, err := consistentArgs(obj.Fns)
diff --git a/lang/funcs/structlookup_polyfunc.go b/lang/funcs/structlookup_polyfunc.go
index 375c03fd..64e02d0d 100644
--- a/lang/funcs/structlookup_polyfunc.go
+++ b/lang/funcs/structlookup_polyfunc.go
@@ -50,6 +50,12 @@ type StructLookupPolyFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *StructLookupPolyFunc) String() string {
+	return StructLookupFuncName
+}
+
 // ArgGen returns the Nth arg name for this function.
 func (obj *StructLookupPolyFunc) ArgGen(index int) (string, error) {
 	seq := []string{"struct", "field"}
diff --git a/lang/funcs/structs/call.go b/lang/funcs/structs/call.go
index e35af2f1..194009a0 100644
--- a/lang/funcs/structs/call.go
+++ b/lang/funcs/structs/call.go
@@ -25,6 +25,11 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// CallFuncName is the unique name identifier for this function.
+	CallFuncName = "call"
+)
+
 // CallFunc is a function that takes in a function and all the args, and passes
 // through the results of running the function call.
 type CallFunc struct {
@@ -45,6 +50,12 @@ type CallFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *CallFunc) String() string {
+	return CallFuncName
+}
+
 // Validate makes sure we've built our struct properly.
 func (obj *CallFunc) Validate() error {
 	if obj.Type == nil {
diff --git a/lang/funcs/structs/composite.go b/lang/funcs/structs/composite.go
index 7af7f679..58dbe604 100644
--- a/lang/funcs/structs/composite.go
+++ b/lang/funcs/structs/composite.go
@@ -25,6 +25,11 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// CompositeFuncName is the unique name identifier for this function.
+	CompositeFuncName = "composite"
+)
+
 // CompositeFunc is a function that passes through the value it receives. It is
 // used to take a series of inputs to a list, map or struct, and return that
 // value as a stream that depends on those inputs. It helps the list, map, and
@@ -40,6 +45,12 @@ type CompositeFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *CompositeFunc) String() string {
+	return CompositeFuncName
+}
+
 // Validate makes sure we've built our struct properly.
 func (obj *CompositeFunc) Validate() error {
 	if obj.Type == nil {
diff --git a/lang/funcs/structs/const.go b/lang/funcs/structs/const.go
index e89e18a5..280e576f 100644
--- a/lang/funcs/structs/const.go
+++ b/lang/funcs/structs/const.go
@@ -24,6 +24,11 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// ConstFuncName is the unique name identifier for this function.
+	ConstFuncName = "const"
+)
+
 // ConstFunc is a function that returns the constant value passed to Value.
 type ConstFunc struct {
 	Value types.Value
@@ -32,6 +37,12 @@ type ConstFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *ConstFunc) String() string {
+	return ConstFuncName
+}
+
 // Validate makes sure we've built our struct properly.
 func (obj *ConstFunc) Validate() error {
 	if obj.Value == nil {
diff --git a/lang/funcs/structs/function.go b/lang/funcs/structs/function.go
index e26f7bbb..38d6cf0d 100644
--- a/lang/funcs/structs/function.go
+++ b/lang/funcs/structs/function.go
@@ -26,6 +26,11 @@ import (
 	"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// FunctionFuncName is the unique name identifier for this function.
+	FunctionFuncName = "function"
+)
+
 // FunctionFunc is a function that passes through the function body it receives.
 type FunctionFunc struct {
 	Type *types.Type // this is the type of the function that we hold
@@ -40,6 +45,12 @@ type FunctionFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *FunctionFunc) String() string {
+	return FunctionFuncName
+}
+
 // fn returns the function that wraps the Func interface if that API is used.
 func (obj *FunctionFunc) fn() (*types.FuncValue, error) {
 	fn := func(args []types.Value) (types.Value, error) {
diff --git a/lang/funcs/structs/if.go b/lang/funcs/structs/if.go
index dade9f44..d177970b 100644
--- a/lang/funcs/structs/if.go
+++ b/lang/funcs/structs/if.go
@@ -24,6 +24,11 @@ import (
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
+const (
+	// IfFuncName is the unique name identifier for this function.
+	IfFuncName = "if"
+)
+
 // IfFunc is a function that passes through the value of the correct branch
 // based on the conditional value it gets.
 type IfFunc struct {
@@ -36,6 +41,12 @@ type IfFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *IfFunc) String() string {
+	return IfFuncName
+}
+
 // Validate tells us if the input struct takes a valid form.
 func (obj *IfFunc) Validate() error {
 	if obj.Type == nil {
diff --git a/lang/funcs/structs/var.go b/lang/funcs/structs/var.go
index faf075f8..0481d5ff 100644
--- a/lang/funcs/structs/var.go
+++ b/lang/funcs/structs/var.go
@@ -25,6 +25,11 @@ import (
 	//"github.com/purpleidea/mgmt/util/errwrap"
 )
 
+const (
+	// VarFuncName is the unique name identifier for this function.
+	VarFuncName = "var"
+)
+
 // VarFunc is a function that passes through a function that came from a bind
 // lookup. It exists so that the reactive function engine type checks correctly.
 type VarFunc struct {
@@ -39,6 +44,12 @@ type VarFunc struct {
 	closeChan chan struct{}
 }
 
+// String returns a simple name for this function. This is needed so this struct
+// can satisfy the pgraph.Vertex interface.
+func (obj *VarFunc) String() string {
+	return VarFuncName
+}
+
 // Validate makes sure we've built our struct properly.
 func (obj *VarFunc) Validate() error {
 	if obj.Type == nil {
diff --git a/lang/interfaces/func.go b/lang/interfaces/func.go
index 7d5aa922..5217e90b 100644
--- a/lang/interfaces/func.go
+++ b/lang/interfaces/func.go
@@ -18,6 +18,7 @@
 package interfaces
 
 import (
+	"fmt"
 	"strings"
 
 	"github.com/purpleidea/mgmt/engine"
@@ -57,6 +58,8 @@ type Init struct {
 // TODO: should we support a static version of this interface for funcs that
 // never change to avoid the overhead of the goroutine and channel listener?
 type Func interface {
+	fmt.Stringer // so that this can be stored as a Vertex
+
 	Validate() error // FIXME: this is only needed for PolyFunc. Get it moved and used!
 
 	// Info returns some information about the function in question, which