diff --git a/config/interpolate_funcs.go b/config/interpolate_funcs.go
index 67523ddb2..7cd7f7476 100644
--- a/config/interpolate_funcs.go
+++ b/config/interpolate_funcs.go
@@ -20,22 +20,38 @@ var Funcs map[string]ast.Function
 
 func init() {
 	Funcs = map[string]ast.Function{
-		"concat":       interpolationFuncConcat(),
-		"element":      interpolationFuncElement(),
-		"file":         interpolationFuncFile(),
-		"format":       interpolationFuncFormat(),
-		"formatlist":   interpolationFuncFormatList(),
-		"index":        interpolationFuncIndex(),
-		"join":         interpolationFuncJoin(),
-		"length":       interpolationFuncLength(),
-		"replace":      interpolationFuncReplace(),
-		"split":        interpolationFuncSplit(),
 		"compact":    interpolationFuncCompact(),
+		"concat":     interpolationFuncConcat(),
+		"element":    interpolationFuncElement(),
+		"file":       interpolationFuncFile(),
+		"format":     interpolationFuncFormat(),
+		"formatlist": interpolationFuncFormatList(),
+		"index":      interpolationFuncIndex(),
+		"join":       interpolationFuncJoin(),
+		"length":     interpolationFuncLength(),
+		"replace":    interpolationFuncReplace(),
+		"split":      interpolationFuncSplit(),
 		"base64encode": interpolationFuncBase64Encode(),
 		"base64decode": interpolationFuncBase64Decode(),
 	}
 }
 
+// interpolationFuncCompact strips a list of multi-variable values
+// (e.g. as returned by "split") of any empty strings.
+func interpolationFuncCompact() ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeString},
+		ReturnType: ast.TypeString,
+		Variadic:   false,
+		Callback: func(args []interface{}) (interface{}, error) {
+			if !IsStringList(args[0].(string)) {
+				return args[0].(string), nil
+			}
+			return CompactStringList(StringList(args[0].(string))).String(), nil
+		},
+	}
+}
+
 // interpolationFuncConcat implements the "concat" function that
 // concatenates multiple strings. This isn't actually necessary anymore
 // since our language supports string concat natively, but for backwards
@@ -280,22 +296,6 @@ func interpolationFuncSplit() ast.Function {
 	}
 }
 
-// interpolationFuncCompact strips a list of values (e.g. as returned by
-// "split") of any empty strings
-func interpolationFuncCompact() ast.Function {
-	return ast.Function{
-		ArgTypes:   []ast.Type{ast.TypeString},
-		ReturnType: ast.TypeString,
-		Variadic:   false,
-		Callback: func(args []interface{}) (interface{}, error) {
-			if !IsStringList(args[0].(string)) {
-				return args[0].(string), nil
-			}
-			return CompactStringList(StringList(args[0].(string))).String(), nil
-		},
-	}
-}
-
 // interpolationFuncLookup implements the "lookup" function that allows
 // dynamic lookups of map types within a Terraform configuration.
 func interpolationFuncLookup(vs map[string]ast.Variable) ast.Function {
diff --git a/config/string_list.go b/config/string_list.go
index d4d1850d0..d68fadfd0 100644
--- a/config/string_list.go
+++ b/config/string_list.go
@@ -24,6 +24,20 @@ type StringList string
 // ["", ""]       => SLDSLDSLD
 const stringListDelim = `B780FFEC-B661-4EB8-9236-A01737AD98B6`
 
+// Takes a Stringlist and returns one without empty strings in it
+func (sl StringList) CompactStringList() StringList {
+	parts := sl.Slice()
+
+	var newlist []string
+	// drop the empty strings
+	for i := range parts {
+		if parts[i] != "" {
+			newlist = append(newlist,  parts[i])
+		}
+	}
+	return NewStringList(newlist)
+}
+
 // Build a StringList from a slice
 func NewStringList(parts []string) StringList {
 	// We have to special case the empty list representation
@@ -74,16 +88,3 @@ func (sl StringList) String() string {
 func IsStringList(s string) bool {
 	return strings.Contains(s, stringListDelim)
 }
-
-func CompactStringList(sl StringList) StringList {
-	parts := sl.Slice()
-
-	var newlist []string
-	// drop the empty strings
-	for i := range parts {
-		if parts[i] != "" {
-			newlist = append(newlist,  parts[i])
-		}
-	}
-	return NewStringList(newlist)
-}