diff --git a/docs/function-guide.md b/docs/function-guide.md
index 8461814c..65184840 100644
--- a/docs/function-guide.md
+++ b/docs/function-guide.md
@@ -124,16 +124,15 @@ An example explains it best:
 ### Example
 
 ```golang
-package simplepoly
-
 import (
 	"fmt"
 
 	"github.com/purpleidea/mgmt/lang/types"
+	"github.com/purpleidea/mgmt/lang/funcs/simplepoly"
 )
 
 func init() {
-	Register("len", []*types.FuncValue{
+	simplepoly.Register("len", []*types.FuncValue{
 		{
 			T: types.NewType("func([]variant) int"),
 			V: Len,
diff --git a/docs/language-guide.md b/docs/language-guide.md
index dbb75546..51946347 100644
--- a/docs/language-guide.md
+++ b/docs/language-guide.md
@@ -285,11 +285,12 @@ class baz($a str, $b) {
 Classes can also be nested within other classes. Here's a contrived example:
 
 ```mcl
+import "fmt"
 class c1($a, $b) {
 	# nested class definition
 	class c2($c) {
 		test $a {
-			stringptr => printf("%s is %d", $b, $c),
+			stringptr => fmt.printf("%s is %d", $b, $c),
 		}
 	}
 
diff --git a/examples/lang/answer.mcl b/examples/lang/answer.mcl
index 2096f728..0de5f3bf 100644
--- a/examples/lang/answer.mcl
+++ b/examples/lang/answer.mcl
@@ -1,4 +1,6 @@
 # it was a lovely surprise to me, when i realized that mgmt had the answer!
+import "fmt"
+import "example"
 print "answer" {
-	msg => printf("the answer to life, the universe, and everything is: %d", answer()),
+	msg => fmt.printf("the answer to life, the universe, and everything is: %d", example.answer()),
 }
diff --git a/examples/lang/contains0.mcl b/examples/lang/contains0.mcl
index e434fc6a..374f8014 100644
--- a/examples/lang/contains0.mcl
+++ b/examples/lang/contains0.mcl
@@ -1,3 +1,6 @@
+import "fmt"
+import "sys"
+
 $set = ["a", "b", "c", "d",]
 
 $c1 = "x1" in ["x1", "x2", "x3",]
@@ -5,18 +8,18 @@ $c2 = 42 in [4, 13, 42,]
 $c3 = "x" in $set
 $c4 = "b" in $set
 
-$s = printf("1: %t, 2: %t, 3: %t, 4: %t\n", $c1, $c2, $c3, $c4)
+$s = fmt.printf("1: %t, 2: %t, 3: %t, 4: %t\n", $c1, $c2, $c3, $c4)
 
 file "/tmp/mgmt/contains" {
 	content => $s,
 }
 
-$x = if hostname() in ["h1", "h3",] {
-	printf("i (%s) am one of the chosen few!\n", hostname())
+$x = if sys.hostname() in ["h1", "h3",] {
+	fmt.printf("i (%s) am one of the chosen few!\n", sys.hostname())
 } else {
-	printf("i (%s) was not chosen :(\n", hostname())
+	fmt.printf("i (%s) was not chosen :(\n", sys.hostname())
 }
 
-file "/tmp/mgmt/hello-${hostname()}" {
+file "/tmp/mgmt/hello-${sys.hostname()}" {
 	content => $x,
 }
diff --git a/examples/lang/datetime1.mcl b/examples/lang/datetime1.mcl
index e7654684..2d7f737b 100644
--- a/examples/lang/datetime1.mcl
+++ b/examples/lang/datetime1.mcl
@@ -1,4 +1,6 @@
-$d = datetime()
+import "datetime"
+
+$d = datetime.now()
 file "/tmp/mgmt/datetime" {
 	content => template("Hello! It is now: {{ datetime_print . }}\n", $d),
 }
diff --git a/examples/lang/datetime2.mcl b/examples/lang/datetime2.mcl
index 16a7e2d1..9ca66dbe 100644
--- a/examples/lang/datetime2.mcl
+++ b/examples/lang/datetime2.mcl
@@ -1,11 +1,14 @@
-$secplusone = datetime() + $ayear
+import "datetime"
+import "sys"
+
+$secplusone = datetime.now() + $ayear
 
 # note the order of the assignment (year can come later in the code)
 $ayear = 60 * 60 * 24 * 365	# is a year in seconds (31536000)
 
 $tmplvalues = struct{year => $secplusone, load => $theload,}
 
-$theload = structlookup(load(), "x1")
+$theload = structlookup(sys.load(), "x1")
 
 if 5 > 3 {
 	file "/tmp/mgmt/datetime" {
diff --git a/examples/lang/datetime3.mcl b/examples/lang/datetime3.mcl
index a5591bdc..5667ad52 100644
--- a/examples/lang/datetime3.mcl
+++ b/examples/lang/datetime3.mcl
@@ -1,11 +1,14 @@
-$secplusone = datetime() + $ayear
+import "datetime"
+import "sys"
+
+$secplusone = datetime.now() + $ayear
 
 # note the order of the assignment (year can come later in the code)
 $ayear = 60 * 60 * 24 * 365	# is a year in seconds (31536000)
 
 $tmplvalues = struct{year => $secplusone, load => $theload, vumeter => $vumeter,}
 
-$theload = structlookup(load(), "x1")
+$theload = structlookup(sys.load(), "x1")
 
 $vumeter = vumeter("====", 10, 0.9)
 
diff --git a/examples/lang/env0.mcl b/examples/lang/env0.mcl
index 4e7c7ea6..18d9c276 100644
--- a/examples/lang/env0.mcl
+++ b/examples/lang/env0.mcl
@@ -1,20 +1,23 @@
 # read and print environment variable
 # env TEST=123 EMPTY= ./mgmt run --tmp-prefix --lang=examples/lang/env0.mcl --converged-timeout=5
 
-$x = getenv("TEST", "321")
+import "fmt"
+import "sys"
+
+$x = sys.getenv("TEST", "321")
 
 print "print1" {
-	msg => printf("the value of the environment variable TEST is: %s", $x),
+	msg => fmt.printf("the value of the environment variable TEST is: %s", $x),
 }
 
-$y = getenv("DOESNOTEXIT", "321")
+$y = sys.getenv("DOESNOTEXIT", "321")
 
 print "print2" {
-	msg => printf("environment variable DOESNOTEXIT does not exist, defaulting to: %s", $y),
+	msg => fmt.printf("environment variable DOESNOTEXIT does not exist, defaulting to: %s", $y),
 }
 
-$z = getenv("EMPTY", "456")
+$z = sys.getenv("EMPTY", "456")
 
 print "print3" {
-	msg => printf("same goes for epmty variables like EMPTY: %s", $z),
+	msg => fmt.printf("same goes for epmty variables like EMPTY: %s", $z),
 }
diff --git a/examples/lang/env1.mcl b/examples/lang/env1.mcl
index 001223d0..aa57c2cb 100644
--- a/examples/lang/env1.mcl
+++ b/examples/lang/env1.mcl
@@ -1,9 +1,12 @@
-$env = env()
+import "fmt"
+import "sys"
+
+$env = sys.env()
 $m = maplookup($env, "GOPATH", "")
 
 print "print0" {
-	msg => if hasenv("GOPATH") {
-		printf("GOPATH is: %s", $m)
+	msg => if sys.hasenv("GOPATH") {
+		fmt.printf("GOPATH is: %s", $m)
 	} else {
 		"GOPATH is missing!"
 	},
diff --git a/examples/lang/exchange0.mcl b/examples/lang/exchange0.mcl
index 97af41e9..731a273c 100644
--- a/examples/lang/exchange0.mcl
+++ b/examples/lang/exchange0.mcl
@@ -5,9 +5,11 @@
 # time ./mgmt run --lang examples/lang/exchange0.mcl --hostname h3 --seeds http://127.0.0.1:2379 --client-urls http://127.0.0.1:2383 --server-urls http://127.0.0.1:2384 --tmp-prefix --no-pgp
 # time ./mgmt run --lang examples/lang/exchange0.mcl --hostname h4 --seeds http://127.0.0.1:2379 --client-urls http://127.0.0.1:2385 --server-urls http://127.0.0.1:2386 --tmp-prefix --no-pgp
 
+import "sys"
+
 $rand = random1(8)
 $exchanged = exchange("keyns", $rand)
 
-file "/tmp/mgmt/exchange-${hostname()}" {
+file "/tmp/mgmt/exchange-${sys.hostname()}" {
 	content => template("Found: {{ . }}\n", $exchanged),
 }
diff --git a/examples/lang/history1.mcl b/examples/lang/history1.mcl
index 541f328b..66c77fd9 100644
--- a/examples/lang/history1.mcl
+++ b/examples/lang/history1.mcl
@@ -1,4 +1,6 @@
-$dt = datetime()
+import "datetime"
+
+$dt = datetime.now()
 
 $hystvalues = {"ix0" => $dt, "ix1" => $dt{1}, "ix2" => $dt{2}, "ix3" => $dt{3},}
 
diff --git a/examples/lang/hostname0.mcl b/examples/lang/hostname0.mcl
index 4538a350..264e410a 100644
--- a/examples/lang/hostname0.mcl
+++ b/examples/lang/hostname0.mcl
@@ -1,4 +1,6 @@
-file "/tmp/mgmt/${hostname()}" {
-	content => "hello from ${hostname()}!\n",
+import "sys"
+
+file "/tmp/mgmt/${sys.hostname()}" {
+	content => "hello from ${sys.hostname()}!\n",
 	state => "exists",
 }
diff --git a/examples/lang/len0.mcl b/examples/lang/len0.mcl
index 251ec3b1..72f320f5 100644
--- a/examples/lang/len0.mcl
+++ b/examples/lang/len0.mcl
@@ -1,9 +1,11 @@
+import "fmt"
+
 $x1 = ["a", "b", "c", "d",]
 print "print4" {
-	msg => printf("length is: %d", len($x1)),
+	msg => fmt.printf("length is: %d", len($x1)),
 }
 
 $x2 = {"a" => 1, "b" => 2, "c" => 3,}
 print "print3" {
-	msg => printf("length is: %d", len($x2)),
+	msg => fmt.printf("length is: %d", len($x2)),
 }
diff --git a/examples/lang/load0.mcl b/examples/lang/load0.mcl
index 960fe4e5..8333b57e 100644
--- a/examples/lang/load0.mcl
+++ b/examples/lang/load0.mcl
@@ -1,9 +1,12 @@
-$theload = load()
+import "fmt"
+import "sys"
+
+$theload = sys.load()
 
 $x1 = structlookup($theload, "x1")
 $x5 = structlookup($theload, "x5")
 $x15 = structlookup($theload, "x15")
 
 print "print1" {
-	msg => printf("load average: %f, %f, %f", $x1, $x5, $x15),
+	msg => fmt.printf("load average: %f, %f, %f", $x1, $x5, $x15),
 }
diff --git a/examples/lang/maplookup1.mcl b/examples/lang/maplookup1.mcl
index 2a7aca28..12f1a366 100644
--- a/examples/lang/maplookup1.mcl
+++ b/examples/lang/maplookup1.mcl
@@ -1,13 +1,15 @@
+import "fmt"
+
 $m = {"k1" => 42, "k2" => 13,}
 
 $found = maplookup($m, "k1", 99)
 
 print "print1" {
-	msg => printf("found value of: %d", $found),
+	msg => fmt.printf("found value of: %d", $found),
 }
 
 $notfound = maplookup($m, "k3", 99)
 
 print "print2" {
-	msg => printf("notfound value of: %d", $notfound),
+	msg => fmt.printf("notfound value of: %d", $notfound),
 }
diff --git a/examples/lang/math1.mcl b/examples/lang/math1.mcl
index 98a46331..518b9914 100644
--- a/examples/lang/math1.mcl
+++ b/examples/lang/math1.mcl
@@ -1,4 +1,6 @@
+import "fmt"
+
 test "t1" {
 	int64 => (4 + 32) * 15 - 8,
-	anotherstr => printf("the answer is: %d", 42),
+	anotherstr => fmt.printf("the answer is: %d", 42),
 }
diff --git a/examples/lang/math2.mcl b/examples/lang/math2.mcl
index 65bf9dfe..664d8582 100644
--- a/examples/lang/math2.mcl
+++ b/examples/lang/math2.mcl
@@ -1,3 +1,6 @@
+import "fmt"
+import "math"
+
 print "print0" {
-	msg => printf("13.0 ^ 4.2 is: %f", pow(13.0, 4.2)),
+	msg => fmt.printf("13.0 ^ 4.2 is: %f", math.pow(13.0, 4.2)),
 }
diff --git a/examples/lang/printf1.mcl b/examples/lang/printf1.mcl
index 9a3b9abf..ab8a97a9 100644
--- a/examples/lang/printf1.mcl
+++ b/examples/lang/printf1.mcl
@@ -1,8 +1,10 @@
+import "fmt"
+
 test "printf-a" {
-	anotherstr => printf("the %s is: %d", "answer", 42),
+	anotherstr => fmt.printf("the %s is: %d", "answer", 42),
 }
 
 $format = "a %s is: %f"
 test "printf-b" {
-	anotherstr => printf($format, "cool number", 3.14159),
+	anotherstr => fmt.printf($format, "cool number", 3.14159),
 }
diff --git a/examples/lang/schedule0.mcl b/examples/lang/schedule0.mcl
index cbbc05f9..2b4979b9 100644
--- a/examples/lang/schedule0.mcl
+++ b/examples/lang/schedule0.mcl
@@ -1,3 +1,5 @@
+import "sys"
+
 # here are all the possible options:
 #$opts = struct{strategy => "rr", max => 3, reuse => false, ttl => 10,}
 
@@ -13,6 +15,6 @@ $set = schedule("xsched", $opts)
 # and if you want, you can omit the options entirely:
 #$set = schedule("xsched")
 
-file "/tmp/mgmt/scheduled-${hostname()}" {
+file "/tmp/mgmt/scheduled-${sys.hostname()}" {
 	content => template("set: {{ . }}\n", $set),
 }
diff --git a/examples/lang/sendrecv3.mcl b/examples/lang/sendrecv3.mcl
index 898c1e98..17c998bf 100644
--- a/examples/lang/sendrecv3.mcl
+++ b/examples/lang/sendrecv3.mcl
@@ -1,3 +1,5 @@
+import "fmt"
+
 $ns = "estate"
 $exchanged = kvlookup($ns)
 $state = maplookup($exchanged, $hostname, "default")
@@ -16,6 +18,6 @@ Exec["exec0"].output -> Kv["kv0"].value
 
 if $state != "default" {
 	file "/tmp/mgmt/state" {
-		content => printf("state: %s\n", $state),
+		content => fmt.printf("state: %s\n", $state),
 	}
 }
diff --git a/examples/lang/structlookup1.mcl b/examples/lang/structlookup1.mcl
index c3812246..45690364 100644
--- a/examples/lang/structlookup1.mcl
+++ b/examples/lang/structlookup1.mcl
@@ -1,13 +1,15 @@
+import "fmt"
+
 $st = struct{f1 => 42, f2 => true, f3 => 3.14,}
 
 $f1 = structlookup($st, "f1")
 
 print "print1" {
-	msg => printf("f1 field is: %d", $f1),
+	msg => fmt.printf("f1 field is: %d", $f1),
 }
 
 $f2 = structlookup($st, "f2")
 
 print "print2" {
-	msg => printf("f2 field is: %t", $f2),
+	msg => fmt.printf("f2 field is: %t", $f2),
 }
diff --git a/examples/lang/template0.mcl b/examples/lang/template0.mcl
index d4a1b09f..5106faa8 100644
--- a/examples/lang/template0.mcl
+++ b/examples/lang/template0.mcl
@@ -1,8 +1,11 @@
+import "fmt"
+import "example"
+
 $answer = 42
-$s = int2str($answer)
+$s = example.int2str($answer)
 
 print "print1" {
-	msg => printf("an str is: %s", $s),
+	msg => fmt.printf("an str is: %s", $s),
 }
 
 print "print2" {
diff --git a/lang/funcs/core/core.go b/lang/funcs/core/core.go
new file mode 100644
index 00000000..68d8a48f
--- /dev/null
+++ b/lang/funcs/core/core.go
@@ -0,0 +1,27 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	// import so the funcs register
+	_ "github.com/purpleidea/mgmt/lang/funcs/core/coredatetime"
+	_ "github.com/purpleidea/mgmt/lang/funcs/core/coreexample"
+	_ "github.com/purpleidea/mgmt/lang/funcs/core/corefmt"
+	_ "github.com/purpleidea/mgmt/lang/funcs/core/coremath"
+	_ "github.com/purpleidea/mgmt/lang/funcs/core/coresys"
+)
diff --git a/lang/funcs/core/coredatetime/coredatetime.go b/lang/funcs/core/coredatetime/coredatetime.go
new file mode 100644
index 00000000..a6f2065a
--- /dev/null
+++ b/lang/funcs/core/coredatetime/coredatetime.go
@@ -0,0 +1,23 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coredatetime
+
+const (
+	// moduleName is the prefix given to all the functions in this module.
+	moduleName = "datetime"
+)
diff --git a/lang/funcs/facts/core/datetime_fact.go b/lang/funcs/core/coredatetime/now_fact.go
similarity index 94%
rename from lang/funcs/facts/core/datetime_fact.go
rename to lang/funcs/core/coredatetime/now_fact.go
index 2b60bccf..22e8229a 100644
--- a/lang/funcs/facts/core/datetime_fact.go
+++ b/lang/funcs/core/coredatetime/now_fact.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package coredatetime
 
 import (
 	"time"
@@ -25,7 +25,7 @@ import (
 )
 
 func init() {
-	facts.Register("datetime", func() facts.Fact { return &DateTimeFact{} }) // must register the fact and name
+	facts.ModuleRegister(moduleName, "now", func() facts.Fact { return &DateTimeFact{} }) // must register the fact and name
 }
 
 // DateTimeFact is a fact which returns the current date and time.
diff --git a/lang/funcs/simple/datetime_print_func.go b/lang/funcs/core/coredatetime/print_func.go
similarity index 87%
rename from lang/funcs/simple/datetime_print_func.go
rename to lang/funcs/core/coredatetime/print_func.go
index 9baf0ab3..3340afef 100644
--- a/lang/funcs/simple/datetime_print_func.go
+++ b/lang/funcs/core/coredatetime/print_func.go
@@ -15,19 +15,19 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coredatetime
 
 import (
 	"fmt"
 	"time"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	// TODO: should we support namespacing these, eg: datetime.print ?
 	// FIXME: consider renaming this to printf, and add in a format string?
-	Register("datetime_print", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "print", &types.FuncValue{
 		T: types.NewType("func(a int) str"),
 		V: func(input []types.Value) (types.Value, error) {
 			epochDelta := input[0].Int()
diff --git a/lang/funcs/simple/answer_func.go b/lang/funcs/core/coreexample/answer_func.go
similarity index 89%
rename from lang/funcs/simple/answer_func.go
rename to lang/funcs/core/coreexample/answer_func.go
index 081daaeb..4841c500 100644
--- a/lang/funcs/simple/answer_func.go
+++ b/lang/funcs/core/coreexample/answer_func.go
@@ -15,9 +15,10 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coreexample
 
 import (
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
@@ -25,7 +26,7 @@ import (
 const Answer = 42
 
 func init() {
-	Register("answer", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "answer", &types.FuncValue{
 		T: types.NewType("func() int"),
 		V: func([]types.Value) (types.Value, error) {
 			return &types.IntValue{V: Answer}, nil
diff --git a/lang/funcs/core/coreexample/coreexample.go b/lang/funcs/core/coreexample/coreexample.go
new file mode 100644
index 00000000..e90c5db0
--- /dev/null
+++ b/lang/funcs/core/coreexample/coreexample.go
@@ -0,0 +1,23 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coreexample
+
+const (
+	// moduleName is the prefix given to all the functions in this module.
+	moduleName = "example"
+)
diff --git a/lang/funcs/simple/example_errorbool_func.go b/lang/funcs/core/coreexample/errorbool_func.go
similarity index 85%
rename from lang/funcs/simple/example_errorbool_func.go
rename to lang/funcs/core/coreexample/errorbool_func.go
index b3e4905e..4fe01ab6 100644
--- a/lang/funcs/simple/example_errorbool_func.go
+++ b/lang/funcs/core/coreexample/errorbool_func.go
@@ -15,17 +15,17 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coreexample
 
 import (
 	"fmt"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	// TODO: should we support namespacing these, eg: example.errorbool ?
-	Register("example_errorbool", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "errorbool", &types.FuncValue{
 		T: types.NewType("func(a bool) str"),
 		V: func(input []types.Value) (types.Value, error) {
 			if input[0].Bool() {
diff --git a/lang/funcs/facts/core/flipflop_fact.go b/lang/funcs/core/coreexample/flipflop_fact.go
similarity index 91%
rename from lang/funcs/facts/core/flipflop_fact.go
rename to lang/funcs/core/coreexample/flipflop_fact.go
index e2c7a70b..cace4d2f 100644
--- a/lang/funcs/facts/core/flipflop_fact.go
+++ b/lang/funcs/core/coreexample/flipflop_fact.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package coreexample
 
 import (
 	"time"
@@ -25,8 +25,7 @@ import (
 )
 
 func init() {
-	// TODO: rename these `play` facts to start with a test_ prefix or similar
-	facts.Register("flipflop", func() facts.Fact { return &FlipFlopFact{} }) // must register the fact and name
+	facts.ModuleRegister(moduleName, "flipflop", 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
diff --git a/lang/funcs/simple/int2str_func.go b/lang/funcs/core/coreexample/int2str_func.go
similarity index 88%
rename from lang/funcs/simple/int2str_func.go
rename to lang/funcs/core/coreexample/int2str_func.go
index c7550f01..f3e007a4 100644
--- a/lang/funcs/simple/int2str_func.go
+++ b/lang/funcs/core/coreexample/int2str_func.go
@@ -15,16 +15,17 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coreexample
 
 import (
 	"fmt"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	Register("int2str", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "int2str", &types.FuncValue{
 		T: types.NewType("func(a int) str"),
 		V: func(input []types.Value) (types.Value, error) {
 			return &types.StrValue{
diff --git a/lang/funcs/core/vumeter_func.go b/lang/funcs/core/coreexample/vumeter_func.go
similarity index 96%
rename from lang/funcs/core/vumeter_func.go
rename to lang/funcs/core/coreexample/vumeter_func.go
index f7b7209e..7032b166 100644
--- a/lang/funcs/core/vumeter_func.go
+++ b/lang/funcs/core/coreexample/vumeter_func.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package coreexample
 
 import (
 	"fmt"
@@ -34,7 +34,7 @@ import (
 )
 
 func init() {
-	funcs.Register("vumeter", func() interfaces.Func { return &VUMeterFunc{} }) // must register the func and name
+	funcs.ModuleRegister(moduleName, "vumeter", func() interfaces.Func { return &VUMeterFunc{} }) // must register the func and name
 }
 
 // VUMeterFunc is a gimmic function to display a vu meter from the microphone.
diff --git a/lang/funcs/core/corefmt/corefmt.go b/lang/funcs/core/corefmt/corefmt.go
new file mode 100644
index 00000000..84ece4c7
--- /dev/null
+++ b/lang/funcs/core/corefmt/corefmt.go
@@ -0,0 +1,23 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package corefmt
+
+const (
+	// moduleName is the prefix given to all the functions in this module.
+	moduleName = "fmt"
+)
diff --git a/lang/funcs/core/printf_polyfunc.go b/lang/funcs/core/corefmt/printf_func.go
similarity index 98%
rename from lang/funcs/core/printf_polyfunc.go
rename to lang/funcs/core/corefmt/printf_func.go
index 2b4b9ddb..f6c796ea 100644
--- a/lang/funcs/core/printf_polyfunc.go
+++ b/lang/funcs/core/corefmt/printf_func.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package corefmt
 
 import (
 	"fmt"
@@ -29,7 +29,7 @@ import (
 )
 
 func init() {
-	funcs.Register("printf", func() interfaces.Func { return &PrintfFunc{} })
+	funcs.ModuleRegister(moduleName, "printf", func() interfaces.Func { return &PrintfFunc{} })
 }
 
 const (
diff --git a/lang/funcs/core/coremath/coremath.go b/lang/funcs/core/coremath/coremath.go
new file mode 100644
index 00000000..89721ead
--- /dev/null
+++ b/lang/funcs/core/coremath/coremath.go
@@ -0,0 +1,23 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coremath
+
+const (
+	// moduleName is the prefix given to all the functions in this module.
+	moduleName = "math"
+)
diff --git a/lang/funcs/simple/math_func.go b/lang/funcs/core/coremath/pow_func.go
similarity index 92%
rename from lang/funcs/simple/math_func.go
rename to lang/funcs/core/coremath/pow_func.go
index e29bef0a..6629d7d9 100644
--- a/lang/funcs/simple/math_func.go
+++ b/lang/funcs/core/coremath/pow_func.go
@@ -15,17 +15,18 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coremath
 
 import (
 	"fmt"
 	"math"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	Register("pow", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "pow", &types.FuncValue{
 		T: types.NewType("func(x float, y float) float"),
 		V: Pow,
 	})
diff --git a/lang/funcs/core/coresys/coresys.go b/lang/funcs/core/coresys/coresys.go
new file mode 100644
index 00000000..d202bf0f
--- /dev/null
+++ b/lang/funcs/core/coresys/coresys.go
@@ -0,0 +1,23 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package coresys
+
+const (
+	// moduleName is the prefix given to all the functions in this module.
+	moduleName = "sys"
+)
diff --git a/lang/funcs/simple/env_func.go b/lang/funcs/core/coresys/env_func.go
similarity index 87%
rename from lang/funcs/simple/env_func.go
rename to lang/funcs/core/coresys/env_func.go
index 34d6a117..8e24dd3f 100644
--- a/lang/funcs/simple/env_func.go
+++ b/lang/funcs/core/coresys/env_func.go
@@ -15,29 +15,30 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simple // TODO: should this be in its own individual package?
+package coresys
 
 import (
 	"os"
 	"strings"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	Register("getenv", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "getenv", &types.FuncValue{
 		T: types.NewType("func(str) str"),
 		V: GetEnv,
 	})
-	Register("defaultenv", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "defaultenv", &types.FuncValue{
 		T: types.NewType("func(str, str) str"),
 		V: DefaultEnv,
 	})
-	Register("hasenv", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "hasenv", &types.FuncValue{
 		T: types.NewType("func(str) bool"),
 		V: HasEnv,
 	})
-	Register("env", &types.FuncValue{
+	simple.ModuleRegister(moduleName, "env", &types.FuncValue{
 		T: types.NewType("func() map{str: str}"),
 		V: Env,
 	})
diff --git a/lang/funcs/facts/core/hostname_fact.go b/lang/funcs/core/coresys/hostname_fact.go
similarity index 92%
rename from lang/funcs/facts/core/hostname_fact.go
rename to lang/funcs/core/coresys/hostname_fact.go
index 88926700..5ea555c7 100644
--- a/lang/funcs/facts/core/hostname_fact.go
+++ b/lang/funcs/core/coresys/hostname_fact.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package coresys
 
 import (
 	"github.com/purpleidea/mgmt/lang/funcs/facts"
@@ -23,7 +23,7 @@ import (
 )
 
 func init() {
-	facts.Register("hostname", func() facts.Fact { return &HostnameFact{} }) // must register the fact and name
+	facts.ModuleRegister(moduleName, "hostname", func() facts.Fact { return &HostnameFact{} }) // must register the fact and name
 }
 
 // HostnameFact is a function that returns the hostname.
diff --git a/lang/funcs/facts/core/load_fact.go b/lang/funcs/core/coresys/load_fact.go
similarity index 94%
rename from lang/funcs/facts/core/load_fact.go
rename to lang/funcs/core/coresys/load_fact.go
index 2402bcee..1a687df3 100644
--- a/lang/funcs/facts/core/load_fact.go
+++ b/lang/funcs/core/coresys/load_fact.go
@@ -15,7 +15,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package core // TODO: should this be in its own individual package?
+package coresys
 
 import (
 	"time"
@@ -31,7 +31,7 @@ const (
 )
 
 func init() {
-	facts.Register("load", func() facts.Fact { return &LoadFact{} }) // must register the fact and name
+	facts.ModuleRegister(moduleName, "load", func() facts.Fact { return &LoadFact{} }) // must register the fact and name
 }
 
 // LoadFact is a fact which returns the current system load.
diff --git a/lang/funcs/facts/core/load_fact_darwin.go b/lang/funcs/core/coresys/load_fact_darwin.go
similarity index 94%
rename from lang/funcs/facts/core/load_fact_darwin.go
rename to lang/funcs/core/coresys/load_fact_darwin.go
index f546c2e5..6d27b484 100644
--- a/lang/funcs/facts/core/load_fact_darwin.go
+++ b/lang/funcs/core/coresys/load_fact_darwin.go
@@ -17,7 +17,7 @@
 
 // +build darwin
 
-package core // TODO: should this be in its own individual package?
+package coresys
 
 /*
 #include <stdlib.h>
diff --git a/lang/funcs/facts/core/load_fact_posix.go b/lang/funcs/core/coresys/load_fact_posix.go
similarity index 95%
rename from lang/funcs/facts/core/load_fact_posix.go
rename to lang/funcs/core/coresys/load_fact_posix.go
index f80c2d99..d9e80720 100644
--- a/lang/funcs/facts/core/load_fact_posix.go
+++ b/lang/funcs/core/coresys/load_fact_posix.go
@@ -17,7 +17,7 @@
 
 // +build !darwin
 
-package core // TODO: should this be in its own individual package?
+package coresys
 
 import (
 	"syscall"
diff --git a/lang/funcs/core/exchange_polyfunc.go b/lang/funcs/core/exchange_func.go
similarity index 100%
rename from lang/funcs/core/exchange_polyfunc.go
rename to lang/funcs/core/exchange_func.go
diff --git a/lang/funcs/simplepoly/len_polyfunc.go b/lang/funcs/core/len_func.go
similarity index 93%
rename from lang/funcs/simplepoly/len_polyfunc.go
rename to lang/funcs/core/len_func.go
index 59632a07..16f43be7 100644
--- a/lang/funcs/simplepoly/len_polyfunc.go
+++ b/lang/funcs/core/len_func.go
@@ -15,16 +15,17 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-package simplepoly // TODO: should this be in its own individual package?
+package core
 
 import (
 	"fmt"
 
+	"github.com/purpleidea/mgmt/lang/funcs/simplepoly"
 	"github.com/purpleidea/mgmt/lang/types"
 )
 
 func init() {
-	Register("len", []*types.FuncValue{
+	simplepoly.Register("len", []*types.FuncValue{
 		{
 			T: types.NewType("func([]variant) int"),
 			V: Len,
diff --git a/lang/funcs/core/schedule_polyfunc.go b/lang/funcs/core/schedule_func.go
similarity index 100%
rename from lang/funcs/core/schedule_polyfunc.go
rename to lang/funcs/core/schedule_func.go
diff --git a/lang/funcs/core/template_polyfunc.go b/lang/funcs/core/template_func.go
similarity index 98%
rename from lang/funcs/core/template_polyfunc.go
rename to lang/funcs/core/template_func.go
index 22f88c4d..3a9a3ee9 100644
--- a/lang/funcs/core/template_polyfunc.go
+++ b/lang/funcs/core/template_func.go
@@ -188,6 +188,8 @@ func (obj *TemplateFunc) run(templateText string, vars types.Value) (string, err
 	// FIXME: should we do this once in init() instead, or in the Register
 	// function in the simple package?
 	// TODO: loop through this map in a sorted, deterministic order
+	// XXX: should this use the scope instead (so imports are used properly) ?
+	// XXX: dots are not valid here, so maybe replace dots with underscores so we can do fmt_print???
 	for name, fn := range simple.RegisteredFuncs {
 		if _, exists := funcMap[name]; exists {
 			obj.init.Logf("warning, existing function named: `%s` exists", name)
diff --git a/lang/funcs/facts/facts.go b/lang/funcs/facts/facts.go
index fb01a61d..7a94bce6 100644
--- a/lang/funcs/facts/facts.go
+++ b/lang/funcs/facts/facts.go
@@ -47,6 +47,12 @@ func Register(name string, fn func() Fact) {
 	RegisteredFacts[name] = fn
 }
 
+// ModuleRegister is exactly like Register, except that it registers within a
+// named module. This is a helper function.
+func ModuleRegister(module, name string, fn func() Fact) {
+	Register(module+funcs.ModuleSep+name, fn)
+}
+
 // Info is a static representation of some information about the fact. It is
 // used for static analysis and type checking. If you break this contract, you
 // might cause a panic.
diff --git a/lang/funcs/funcs.go b/lang/funcs/funcs.go
index ea79509d..21518f90 100644
--- a/lang/funcs/funcs.go
+++ b/lang/funcs/funcs.go
@@ -20,10 +20,18 @@ package funcs
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/purpleidea/mgmt/lang/interfaces"
 )
 
+const (
+	// ModuleSep is the character used for the module scope separation. For
+	// example when using `fmt.printf` or `math.sin` this is the char used.
+	// It is included here for convenience when importing this package.
+	ModuleSep = interfaces.ModuleSep
+)
+
 // registeredFuncs is a global map of all possible funcs which can be used. You
 // should never touch this map directly. Use methods like Register instead. It
 // includes implementations which also satisfy PolyFunc as well.
@@ -32,15 +40,33 @@ var registeredFuncs = make(map[string]func() interfaces.Func) // must initialize
 // Register takes a func and its name and makes it available for use. It is
 // commonly called in the init() method of the func at program startup. There is
 // no matching Unregister function. You may also register functions which
-// satisfy the PolyFunc interface.
+// satisfy the PolyFunc interface. To register a function which lives in a
+// module, you must join the module name to the function name with the ModuleSep
+// character. It is defined as a const and is probably the period character.
 func Register(name string, fn func() interfaces.Func) {
 	if _, exists := registeredFuncs[name]; exists {
 		panic(fmt.Sprintf("a func named %s is already registered", name))
 	}
+
+	// can't contain more than one period in a row
+	if strings.Index(name, ModuleSep+ModuleSep) >= 0 {
+		panic(fmt.Sprintf("a func named %s is invalid", name))
+	}
+	// can't start or end with a period
+	if strings.HasPrefix(name, ModuleSep) || strings.HasSuffix(name, ModuleSep) {
+		panic(fmt.Sprintf("a func named %s is invalid", name))
+	}
+
 	//gob.Register(fn())
 	registeredFuncs[name] = fn
 }
 
+// ModuleRegister is exactly like Register, except that it registers within a
+// named module.
+func ModuleRegister(module, name string, fn func() interfaces.Func) {
+	Register(module+ModuleSep+name, fn)
+}
+
 // Lookup returns a pointer to the function's struct. It may be convertible to a
 // PolyFunc if the particular function implements those additional methods.
 func Lookup(name string) (interfaces.Func, error) {
@@ -50,3 +76,21 @@ func Lookup(name string) (interfaces.Func, error) {
 	}
 	return f(), nil
 }
+
+// LookupPrefix returns a map of names to functions that start with a module
+// prefix. This search automatically adds the period separator. So if you want
+// functions in the `fmt` package, search for `fmt`, not `fmt.` and it will find
+// all the correctly registered functions. This removes that prefix from the
+// result in the map keys that it returns.
+func LookupPrefix(prefix string) (map[string]interfaces.Func, error) {
+	result := make(map[string]interfaces.Func)
+	for name, f := range registeredFuncs {
+		sep := prefix + ModuleSep
+		if !strings.HasPrefix(name, sep) {
+			continue
+		}
+		s := strings.TrimPrefix(name, sep) // TODO: is it okay to remove the prefix?
+		result[s] = f()                    // build
+	}
+	return result, nil
+}
diff --git a/lang/funcs/simple/simple.go b/lang/funcs/simple/simple.go
index 37fba1e2..079e9f96 100644
--- a/lang/funcs/simple/simple.go
+++ b/lang/funcs/simple/simple.go
@@ -42,6 +42,12 @@ func Register(name string, fn *types.FuncValue) {
 	funcs.Register(name, func() interfaces.Func { return &simpleFunc{Fn: fn} })
 }
 
+// ModuleRegister is exactly like Register, except that it registers within a
+// named module. This is a helper function.
+func ModuleRegister(module, name string, fn *types.FuncValue) {
+	Register(module+funcs.ModuleSep+name, fn)
+}
+
 // simpleFunc 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 simpleFunc struct {
diff --git a/lang/funcs/simplepoly/simplepoly.go b/lang/funcs/simplepoly/simplepoly.go
index 87211403..cce234ed 100644
--- a/lang/funcs/simplepoly/simplepoly.go
+++ b/lang/funcs/simplepoly/simplepoly.go
@@ -62,6 +62,12 @@ func Register(name string, fns []*types.FuncValue) {
 	funcs.Register(name, func() interfaces.Func { return &simplePolyFunc{Fns: fns} })
 }
 
+// ModuleRegister is exactly like Register, except that it registers within a
+// named module. This is a helper function.
+func ModuleRegister(module, name string, fns []*types.FuncValue) {
+	Register(module+funcs.ModuleSep+name, fns)
+}
+
 // simplePolyFunc is a scaffolding function struct which fulfills the
 // boiler-plate for the function API, but that can run a very simple, static,
 // pure, polymorphic function.
diff --git a/lang/interfaces/const.go b/lang/interfaces/const.go
new file mode 100644
index 00000000..38d2687d
--- /dev/null
+++ b/lang/interfaces/const.go
@@ -0,0 +1,24 @@
+// Mgmt
+// Copyright (C) 2013-2018+ James Shubin and the project contributors
+// Written by James Shubin <james@shubin.ca> and the project contributors
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package interfaces
+
+const (
+	// ModuleSep is the character used for the module scope separation. For
+	// example when using `fmt.printf` or `math.sin` this is the char used.
+	ModuleSep = "."
+)
diff --git a/lang/lang.go b/lang/lang.go
index 500ff5c9..83cccc49 100644
--- a/lang/lang.go
+++ b/lang/lang.go
@@ -24,10 +24,7 @@ import (
 
 	"github.com/purpleidea/mgmt/engine"
 	"github.com/purpleidea/mgmt/lang/funcs"
-	_ "github.com/purpleidea/mgmt/lang/funcs/core"       // import so the funcs register
-	_ "github.com/purpleidea/mgmt/lang/funcs/facts/core" // import so the facts register
-	_ "github.com/purpleidea/mgmt/lang/funcs/simple"     // import so the funcs register
-	_ "github.com/purpleidea/mgmt/lang/funcs/simplepoly" // import so the funcs register
+	_ "github.com/purpleidea/mgmt/lang/funcs/core" // import so the funcs register
 	"github.com/purpleidea/mgmt/lang/interfaces"
 	"github.com/purpleidea/mgmt/lang/unification"
 	"github.com/purpleidea/mgmt/pgraph"
diff --git a/lang/lang_test.go b/lang/lang_test.go
index 49ddf6f0..c729b4f4 100644
--- a/lang/lang_test.go
+++ b/lang/lang_test.go
@@ -26,7 +26,7 @@ import (
 
 	"github.com/purpleidea/mgmt/engine"
 	"github.com/purpleidea/mgmt/engine/resources"
-	_ "github.com/purpleidea/mgmt/lang/funcs/facts/core" // load facts
+	_ "github.com/purpleidea/mgmt/lang/funcs/core" // import so the funcs register
 	"github.com/purpleidea/mgmt/pgraph"
 	"github.com/purpleidea/mgmt/util"
 
@@ -497,9 +497,10 @@ func TestInterpretMany(t *testing.T) {
 	//	values = append(values, test{
 	//		name: "double include different printf types allowed",
 	//		code: `
+	//		import "fmt"
 	//		class c1($a, $b) {
 	//			test $a {
-	//				stringptr => printf("value is: %v", $b),
+	//				stringptr => fmt.printf("value is: %v", $b),
 	//			}
 	//		}
 	//		include c1("t1", "hello")
@@ -667,6 +668,8 @@ func TestInterpretMany(t *testing.T) {
 		values = append(values, test{
 			name: "nested classes 1",
 			code: `
+			import "fmt"
+
 			include c1("t1", "hello") # test["t1"] -> hello is 42
 			include c1("t2", "world") # test["t2"] -> world is 13
 
@@ -674,7 +677,7 @@ func TestInterpretMany(t *testing.T) {
 				# nested class definition
 				class c2($c) {
 					test $a {
-						stringptr => printf("%s is %d", $b, $c),
+						stringptr => fmt.printf("%s is %d", $b, $c),
 					}
 				}
 
@@ -693,6 +696,8 @@ func TestInterpretMany(t *testing.T) {
 		values = append(values, test{
 			name: "nested classes out of scope 1",
 			code: `
+			import "fmt"
+
 			include c1("t1", "hello") # test["t1"] -> hello is 42
 			include c2(99) # out of scope
 
@@ -700,7 +705,7 @@ func TestInterpretMany(t *testing.T) {
 				# nested class definition
 				class c2($c) {
 					test $a {
-						stringptr => printf("%s is %d", $b, $c),
+						stringptr => fmt.printf("%s is %d", $b, $c),
 					}
 				}
 
@@ -742,13 +747,14 @@ func TestInterpretMany(t *testing.T) {
 	//	values = append(values, test{
 	//		name: "recursive classes 1",
 	//		code: `
+	//		import "fmt"
 	//		$max = 3
 	//		include c1(0) # start at zero
 	//		# test["done"] -> count is 3
 	//		class c1($count) {
 	//			if $count == $max {
 	//				test "done" {
-	//					stringptr => printf("count is %d", $count),
+	//					stringptr => fmt.printf("count is %d", $count),
 	//				}
 	//			} else {
 	//				include c1($count + 1)
@@ -779,6 +785,7 @@ func TestInterpretMany(t *testing.T) {
 	//	values = append(values, test{
 	//		name: "recursive classes 2",
 	//		code: `
+	//		import "fmt"
 	//		include c1("ix", 3)
 	//		# test["ix:3"] -> count is 3
 	//		# test["ix:2"] -> count is 2
@@ -787,12 +794,12 @@ func TestInterpretMany(t *testing.T) {
 	//		class c1($name, $count) {
 	//			if $count == 0 {
 	//				test "zero" {
-	//					stringptr => printf("count is %d", $count),
+	//					stringptr => fmt.printf("count is %d", $count),
 	//				}
 	//			} else {
 	//				include c1($name, $count - 1)
 	//				test "${name}:${count}" {
-	//					stringptr => printf("count is %d", $count),
+	//					stringptr => fmt.printf("count is %d", $count),
 	//				}
 	//			}
 	//		}
@@ -806,12 +813,13 @@ func TestInterpretMany(t *testing.T) {
 		values = append(values, test{
 			name: "recursive classes fail 1",
 			code: `
+			import "fmt"
 			$max = 3
 			include c1(0) # start at zero
 			class c1($count) {
 				if $count == $max {
 					test "done" {
-						stringptr => printf("count is %d", $count),
+						stringptr => fmt.printf("count is %d", $count),
 					}
 				} else {
 					include c1($count + 1) # recursion not supported atm
@@ -826,12 +834,13 @@ func TestInterpretMany(t *testing.T) {
 		values = append(values, test{
 			name: "recursive classes fail 2",
 			code: `
+			import "fmt"
 			$max = 5
 			include c1(0) # start at zero
 			class c1($count) {
 				if $count == $max {
 					test "done" {
-						stringptr => printf("count is %d", $count),
+						stringptr => fmt.printf("count is %d", $count),
 					}
 				} else {
 					include c2($count + 1) # recursion not supported atm
@@ -840,7 +849,7 @@ func TestInterpretMany(t *testing.T) {
 			class c2($count) {
 				if $count == $max {
 					test "done" {
-						stringptr => printf("count is %d", $count),
+						stringptr => fmt.printf("count is %d", $count),
 					}
 				} else {
 					include c1($count + 1) # recursion not supported atm
diff --git a/test/shell/env0.mcl b/test/shell/env0.mcl
index 530d16e4..baa22dfc 100644
--- a/test/shell/env0.mcl
+++ b/test/shell/env0.mcl
@@ -1,19 +1,22 @@
-$tmpdir = defaultenv("TMPDIR", "/tmp")
+import "fmt"
+import "sys"
 
-$x = getenv("TEST")
-$y = getenv("DOESNOTEXIST")
-$z = getenv("EMPTY")
+$tmpdir = sys.defaultenv("TMPDIR", "/tmp")
 
-$a = defaultenv("TEST", "321")
-$b = defaultenv("DOESNOTEXIST", "321")
-$c = defaultenv("EMPTY", "456")
+$x = sys.getenv("TEST")
+$y = sys.getenv("DOESNOTEXIST")
+$z = sys.getenv("EMPTY")
 
-$t = hasenv("TEST")
-$f = hasenv("DOESNOTEXIST")
+$a = sys.defaultenv("TEST", "321")
+$b = sys.defaultenv("DOESNOTEXIST", "321")
+$c = sys.defaultenv("EMPTY", "456")
 
-$env = env()
+$t = sys.hasenv("TEST")
+$f = sys.hasenv("DOESNOTEXIST")
+
+$env = sys.env()
 $m = maplookup($env, "TEST", "321")
 
 file "${tmpdir}/environ" {
-	content => printf("%s,%s,%s:%s,%s,%s:%t,%t:%s", $x, $y, $z, $a, $b, $c, $t, $f, $m),
+	content => fmt.printf("%s,%s,%s:%s,%s,%s:%t,%t:%s", $x, $y, $z, $a, $b, $c, $t, $f, $m),
 }
diff --git a/test/shell/load0.sh b/test/shell/load0.sh
index 169306d4..94b0eadd 100755
--- a/test/shell/load0.sh
+++ b/test/shell/load0.sh
@@ -25,14 +25,17 @@ if [[ ! "$tmpdir" =~ "/tmp" ]]; then
 fi
 
 cat > "$tmpdir/load0.mcl" <<EOF
-\$theload = load()
+import "fmt"
+import "sys"
+
+\$theload = sys.load()
 
 \$x1 = structlookup(\$theload, "x1")
 \$x5 = structlookup(\$theload, "x5")
 \$x15 = structlookup(\$theload, "x15")
 
 file "${tmpdir}/loadavg" {
-	content => printf("load average: %f, %f, %f", \$x1, \$x5, \$x15),
+	content => fmt.printf("load average: %f, %f, %f", \$x1, \$x5, \$x15),
 	state => "exists",
 }
 EOF