diff --git a/Makefile b/Makefile
index 7814c8df..d4ac491c 100644
--- a/Makefile
+++ b/Makefile
@@ -46,11 +46,6 @@ test: debug
 	@ $(MAKE) -f script/wren.mk MODE=debug test
 	@ ./script/test.py $(suite)
 
-# Take the contents of the scripts under builtin/ and copy them into their
-# respective wren_<name>.c source files.
-builtin:
-	@ ./script/generate_builtins.py
-
 # Generate the Wren site.
 docs:
 	@ ./script/generate_docs.py
diff --git a/builtin/README.md b/builtin/README.md
index ccbb79a2..dc9b74b3 100644
--- a/builtin/README.md
+++ b/builtin/README.md
@@ -1,7 +1,9 @@
-The Wren scripts in this directory get converted to C string literals and then
-inserted into their respective .c files so that the interpreter can load them
-directly without having to do any file IO.
+The Wren scripts in this directory get converted to C string literals into files
+with a `.wren.inc` extension. Those are then `#includ`ed into their respective
+`.c` files so that the interpreter can load them directly without having to do
+any file IO.
 
-The script that does this copying is `script/generate_builtins.py`.
+The script that does this translation is `script/wren_to_c_string.py`.
 
-You can invoke using `make builtin`.
\ No newline at end of file
+When any of the ".wren" files in here are changed, the Makefile automatically
+updates the generated C headers.
diff --git a/script/generate_builtins.py b/script/generate_builtins.py
deleted file mode 100755
index 0edea337..00000000
--- a/script/generate_builtins.py
+++ /dev/null
@@ -1,45 +0,0 @@
-#!/usr/bin/env python
-# coding: utf-8
-
-import glob
-import os.path
-import re
-
-PATTERN = re.compile(r'LibSource =\n("(.|[\n])*?);')
-
-def copy_builtin(filename, out_prefix):
-  name = os.path.basename(filename)
-  name = name.split('.')[0]
-
-  with open(filename, "r") as f:
-    lines = f.readlines()
-
-  wren_source = ""
-  for line in lines:
-    line = line.replace('"', "\\\"")
-    line = line.replace("\n", "\\n\"")
-    if wren_source: wren_source += "\n"
-    wren_source += '"' + line
-
-  # re.sub() will unescape escape sequences, but we want them to stay escapes
-  # in the C string literal.
-  wren_source = wren_source.replace('\\', '\\\\')
-
-  constant = "LibSource =\n" + wren_source + ";"
-
-  with open(out_prefix + name + ".c", "r") as f:
-    c_source = f.read()
-
-  c_source = PATTERN.sub(constant, c_source)
-
-  with open(out_prefix + name + ".c", "w") as f:
-    f.write(c_source)
-
-  print(filename.ljust(25) + " → " + out_prefix + name + ".c")
-
-
-for f in glob.iglob("builtin/*.wren"):
-  copy_builtin(f, "src/vm/wren_")
-
-for f in glob.iglob("src/module/*.wren"):
-  copy_builtin(f, "src/module/")
diff --git a/script/wren.mk b/script/wren.mk
index 2dc5bb54..1b6fdb95 100644
--- a/script/wren.mk
+++ b/script/wren.mk
@@ -22,10 +22,10 @@
 CLI_HEADERS  := $(wildcard src/cli/*.h)
 CLI_SOURCES  := $(wildcard src/cli/*.c)
 
-MODULE_HEADERS   := $(wildcard src/module/*.h)
+MODULE_HEADERS   := $(wildcard src/module/*.h) $(wildcard src/module/*.wren.inc)
 MODULE_SOURCES   := $(wildcard src/module/*.c)
 
-VM_HEADERS   := $(wildcard src/vm/*.h)
+VM_HEADERS   := $(wildcard src/vm/*.h) $(wildcard src/vm/*.wren.inc)
 VM_SOURCES   := $(wildcard src/vm/*.c)
 
 TEST_HEADERS := $(wildcard test/api/*.h)
@@ -192,4 +192,11 @@ $(LIBUV_DIR)/build/gyp/gyp: script/libuv.py
 $(LIBUV): $(LIBUV_DIR)/build/gyp/gyp script/libuv.py
 	@ ./script/libuv.py build $(LIBUV_ARCH)
 
+# Wren modules that get compiled into the binary as C strings.
+src/vm/wren_%.wren.inc: builtin/%.wren script/wren_to_c_string.py
+	@ ./script/wren_to_c_string.py $@ $<
+
+src/module/%.wren.inc: src/module/%.wren script/wren_to_c_string.py
+	@ ./script/wren_to_c_string.py $@ $<
+
 .PHONY: all cli test vm
diff --git a/script/wren_to_c_string.py b/script/wren_to_c_string.py
new file mode 100755
index 00000000..445b7be8
--- /dev/null
+++ b/script/wren_to_c_string.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+import argparse
+import glob
+import os.path
+import re
+
+# The source for the Wren modules that are built into the VM or CLI are turned
+# include C string literals. This way they can be compiled directly into the
+# code so that file IO is not needed to find and read them.
+#
+# These string literals are stored in files with a ".wren.inc" extension and
+# #included directly by other source files. This generates a ".wren.inc" file
+# given a ".wren" module.
+
+PREAMBLE = """// Generated automatically from {0}. Do not edit.
+static const char* {1}ModuleSource =
+{2};
+"""
+
+def wren_to_c_string(input_path, wren_source_lines, module):
+  wren_source = ""
+  for line in wren_source_lines:
+    line = line.replace('"', "\\\"")
+    line = line.replace("\n", "\\n\"")
+    if wren_source: wren_source += "\n"
+    wren_source += '"' + line
+
+  return PREAMBLE.format(input_path, module, wren_source)
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Convert a Wren library to a C string literal.")
+  parser.add_argument("output", help="The output file to write")
+  parser.add_argument("input", help="The source .wren file")
+
+  args = parser.parse_args()
+
+  with open(args.input, "r") as f:
+    wren_source_lines = f.readlines()
+
+  module = os.path.splitext(os.path.basename(args.input))[0]
+  c_source = wren_to_c_string(args.input, wren_source_lines, module)
+
+  with open(args.output, "w") as f:
+    f.write(c_source)
+
+  print("        str " + args.input)
+
+
+main()
diff --git a/src/module/timer.c b/src/module/timer.c
index 0862ac75..9046d5f5 100644
--- a/src/module/timer.c
+++ b/src/module/timer.c
@@ -7,43 +7,7 @@
 #include "wren.h"
 #include "vm.h"
 
-// This is generated from builtin/module/timer.wren. Do not edit here.
-static const char* timerLibSource =
-"class Timer {\n"
-"  static sleep(milliseconds) {\n"
-"    if (!(milliseconds is Num)) Fiber.abort(\"Milliseconds must be a number.\")\n"
-"    if (milliseconds < 0) Fiber.abort(\"Milliseconds cannot be negative.\")\n"
-"    startTimer_(milliseconds, Fiber.current)\n"
-"\n"
-"    runNextScheduled_()\n"
-"  }\n"
-"\n"
-"  // TODO: Once the CLI modules are more fleshed out, find a better place to\n"
-"  // put this.\n"
-"  static schedule(callable) {\n"
-"    if (__scheduled == null) __scheduled = []\n"
-"    __scheduled.add(Fiber.new {\n"
-"      callable.call()\n"
-"      runNextScheduled_()\n"
-"    })\n"
-"  }\n"
-"\n"
-"  foreign static startTimer_(milliseconds, fiber)\n"
-"\n"
-"  // Called by native code.\n"
-"  static resumeTimer_(fiber) {\n"
-"    fiber.transfer()\n"
-"  }\n"
-"\n"
-"  static runNextScheduled_() {\n"
-"    if (__scheduled == null || __scheduled.isEmpty) {\n"
-"      Fiber.suspend()\n"
-"    } else {\n"
-"      __scheduled.removeAt(0).transfer()\n"
-"    }\n"
-"  }\n"
-"}\n"
-"\n";
+#include "timer.wren.inc"
 
 // The Wren method to call when a timer has completed.
 static WrenValue* resumeTimer;
@@ -58,7 +22,7 @@ static void timerCloseCallback(uv_handle_t* handle)
 static void timerCallback(uv_timer_t* handle)
 {
   WrenValue* fiber = (WrenValue*)handle->data;
-  
+
   // Tell libuv that we don't need the timer anymore.
   uv_close((uv_handle_t*)handle, timerCloseCallback);
 
@@ -74,24 +38,24 @@ static void startTimer(WrenVM* vm)
   {
     resumeTimer = wrenGetMethod(vm, "timer", "Timer", "resumeTimer_(_)");
   }
-  
+
   int milliseconds = (int)wrenGetArgumentDouble(vm, 1);
   WrenValue* fiber = wrenGetArgumentValue(vm, 2);
-  
+
   // Store the fiber to resume when the timer completes.
   uv_timer_t* handle = (uv_timer_t*)malloc(sizeof(uv_timer_t));
   handle->data = fiber;
-  
+
   uv_timer_init(getLoop(), handle);
   uv_timer_start(handle, timerCallback, milliseconds, 0);
 }
 
 char* timerGetSource()
 {
-  size_t length = strlen(timerLibSource);
+  size_t length = strlen(timerModuleSource);
   char* copy = (char*)malloc(length + 1);
-  strncpy(copy, timerLibSource, length + 1);
-  
+  strncpy(copy, timerModuleSource, length + 1);
+
   return copy;
 }
 
@@ -101,7 +65,7 @@ WrenForeignMethodFn timerBindForeign(
   if (strcmp(className, "Timer") != 0) return NULL;
 
   if (isStatic && strcmp(signature, "startTimer_(_,_)") == 0) return startTimer;
-  
+
   return NULL;
 }
 
diff --git a/src/module/timer.wren b/src/module/timer.wren
index 7dc173f5..d358ebec 100644
--- a/src/module/timer.wren
+++ b/src/module/timer.wren
@@ -32,4 +32,3 @@ class Timer {
     }
   }
 }
-
diff --git a/src/module/timer.wren.inc b/src/module/timer.wren.inc
new file mode 100644
index 00000000..fbb18daf
--- /dev/null
+++ b/src/module/timer.wren.inc
@@ -0,0 +1,36 @@
+// Generated automatically from src/module/timer.wren. Do not edit.
+static const char* timerModuleSource =
+"class Timer {\n"
+"  static sleep(milliseconds) {\n"
+"    if (!(milliseconds is Num)) Fiber.abort(\"Milliseconds must be a number.\")\n"
+"    if (milliseconds < 0) Fiber.abort(\"Milliseconds cannot be negative.\")\n"
+"    startTimer_(milliseconds, Fiber.current)\n"
+"\n"
+"    runNextScheduled_()\n"
+"  }\n"
+"\n"
+"  // TODO: Once the CLI modules are more fleshed out, find a better place to\n"
+"  // put this.\n"
+"  static schedule(callable) {\n"
+"    if (__scheduled == null) __scheduled = []\n"
+"    __scheduled.add(Fiber.new {\n"
+"      callable.call()\n"
+"      runNextScheduled_()\n"
+"    })\n"
+"  }\n"
+"\n"
+"  foreign static startTimer_(milliseconds, fiber)\n"
+"\n"
+"  // Called by native code.\n"
+"  static resumeTimer_(fiber) {\n"
+"    fiber.transfer()\n"
+"  }\n"
+"\n"
+"  static runNextScheduled_() {\n"
+"    if (__scheduled == null || __scheduled.isEmpty) {\n"
+"      Fiber.suspend()\n"
+"    } else {\n"
+"      __scheduled.removeAt(0).transfer()\n"
+"    }\n"
+"  }\n"
+"}\n";
diff --git a/src/vm/wren_core.c b/src/vm/wren_core.c
index b45494b2..3bd48e24 100644
--- a/src/vm/wren_core.c
+++ b/src/vm/wren_core.c
@@ -10,223 +10,7 @@
 #include "wren_primitive.h"
 #include "wren_value.h"
 
-// This string literal is generated automatically from core. Do not edit.
-static const char* coreLibSource =
-"class Bool {}\n"
-"class Fiber {}\n"
-"class Fn {}\n"
-"class Null {}\n"
-"class Num {}\n"
-"\n"
-"class Sequence {\n"
-"  all(f) {\n"
-"    var result = true\n"
-"    for (element in this) {\n"
-"      result = f.call(element)\n"
-"      if (!result) return result\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  any(f) {\n"
-"    var result = false\n"
-"    for (element in this) {\n"
-"      result = f.call(element)\n"
-"      if (result) return result\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  contains(element) {\n"
-"    for (item in this) {\n"
-"      if (element == item) return true\n"
-"    }\n"
-"    return false\n"
-"  }\n"
-"\n"
-"  count {\n"
-"    var result = 0\n"
-"    for (element in this) {\n"
-"      result = result + 1\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  count(f) {\n"
-"    var result = 0\n"
-"    for (element in this) {\n"
-"      if (f.call(element)) result = result + 1\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  each(f) {\n"
-"    for (element in this) {\n"
-"      f.call(element)\n"
-"    }\n"
-"  }\n"
-"\n"
-"  isEmpty { iterate(null) ? false : true }\n"
-"\n"
-"  map(transformation) { MapSequence.new(this, transformation) }\n"
-"\n"
-"  where(predicate) { WhereSequence.new(this, predicate) }\n"
-"\n"
-"  reduce(acc, f) {\n"
-"    for (element in this) {\n"
-"      acc = f.call(acc, element)\n"
-"    }\n"
-"    return acc\n"
-"  }\n"
-"\n"
-"  reduce(f) {\n"
-"    var iter = iterate(null)\n"
-"    if (!iter) Fiber.abort(\"Can't reduce an empty sequence.\")\n"
-"\n"
-"    // Seed with the first element.\n"
-"    var result = iteratorValue(iter)\n"
-"    while (iter = iterate(iter)) {\n"
-"      result = f.call(result, iteratorValue(iter))\n"
-"    }\n"
-"\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  join { join(\"\") }\n"
-"\n"
-"  join(sep) {\n"
-"    var first = true\n"
-"    var result = \"\"\n"
-"\n"
-"    for (element in this) {\n"
-"      if (!first) result = result + sep\n"
-"      first = false\n"
-"      result = result + element.toString\n"
-"    }\n"
-"\n"
-"    return result\n"
-"  }\n"
-"\n"
-"  toList {\n"
-"    var result = List.new()\n"
-"    for (element in this) {\n"
-"      result.add(element)\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"}\n"
-"\n"
-"class MapSequence is Sequence {\n"
-"  construct new(sequence, fn) {\n"
-"    _sequence = sequence\n"
-"    _fn = fn\n"
-"  }\n"
-"\n"
-"  iterate(iterator) { _sequence.iterate(iterator) }\n"
-"  iteratorValue(iterator) { _fn.call(_sequence.iteratorValue(iterator)) }\n"
-"}\n"
-"\n"
-"class WhereSequence is Sequence {\n"
-"  construct new(sequence, fn) {\n"
-"    _sequence = sequence\n"
-"    _fn = fn\n"
-"  }\n"
-"\n"
-"  iterate(iterator) {\n"
-"    while (iterator = _sequence.iterate(iterator)) {\n"
-"      if (_fn.call(_sequence.iteratorValue(iterator))) break\n"
-"    }\n"
-"    return iterator\n"
-"  }\n"
-"\n"
-"  iteratorValue(iterator) { _sequence.iteratorValue(iterator) }\n"
-"}\n"
-"\n"
-"class String is Sequence {\n"
-"  bytes { StringByteSequence.new(this) }\n"
-"  codePoints { StringCodePointSequence.new(this) }\n"
-"}\n"
-"\n"
-"class StringByteSequence is Sequence {\n"
-"  construct new(string) {\n"
-"    _string = string\n"
-"  }\n"
-"\n"
-"  [index] { _string.byteAt_(index) }\n"
-"  iterate(iterator) { _string.iterateByte_(iterator) }\n"
-"  iteratorValue(iterator) { _string.byteAt_(iterator) }\n"
-"\n"
-"  count { _string.byteCount_ }\n"
-"}\n"
-"\n"
-"class StringCodePointSequence is Sequence {\n"
-"  construct new(string) {\n"
-"    _string = string\n"
-"  }\n"
-"\n"
-"  [index] { _string.codePointAt_(index) }\n"
-"  iterate(iterator) { _string.iterate(iterator) }\n"
-"  iteratorValue(iterator) { _string.codePointAt_(iterator) }\n"
-"\n"
-"  count { _string.count }\n"
-"}\n"
-"\n"
-"class List is Sequence {\n"
-"  addAll(other) {\n"
-"    for (element in other) {\n"
-"      add(element)\n"
-"    }\n"
-"    return other\n"
-"  }\n"
-"\n"
-"  toString { \"[\" + join(\", \") + \"]\" }\n"
-"\n"
-"  +(other) {\n"
-"    var result = this[0..-1]\n"
-"    for (element in other) {\n"
-"      result.add(element)\n"
-"    }\n"
-"    return result\n"
-"  }\n"
-"}\n"
-"\n"
-"class Map {\n"
-"  keys { MapKeySequence.new(this) }\n"
-"  values { MapValueSequence.new(this) }\n"
-"\n"
-"  toString {\n"
-"    var first = true\n"
-"    var result = \"{\"\n"
-"\n"
-"    for (key in keys) {\n"
-"      if (!first) result = result + \", \"\n"
-"      first = false\n"
-"      result = result + key.toString + \": \" + this[key].toString\n"
-"    }\n"
-"\n"
-"    return result + \"}\"\n"
-"  }\n"
-"}\n"
-"\n"
-"class MapKeySequence is Sequence {\n"
-"  construct new(map) {\n"
-"    _map = map\n"
-"  }\n"
-"\n"
-"  iterate(n) { _map.iterate_(n) }\n"
-"  iteratorValue(iterator) { _map.keyIteratorValue_(iterator) }\n"
-"}\n"
-"\n"
-"class MapValueSequence is Sequence {\n"
-"  construct new(map) {\n"
-"    _map = map\n"
-"  }\n"
-"\n"
-"  iterate(n) { _map.iterate_(n) }\n"
-"  iteratorValue(iterator) { _map.valueIteratorValue_(iterator) }\n"
-"}\n"
-"\n"
-"class Range is Sequence {}\n";
+#include "wren_core.wren.inc"
 
 DEF_PRIMITIVE(bool_not)
 {
@@ -304,7 +88,7 @@ static PrimitiveResult runFiber(WrenVM* vm, ObjFiber* fiber, Value* args,
   if (isCall)
   {
     if (fiber->caller != NULL) RETURN_ERROR("Fiber has already been called.");
-    
+
     // Remember who ran it.
     fiber->caller = vm->fiber;
   }
@@ -315,21 +99,21 @@ static PrimitiveResult runFiber(WrenVM* vm, ObjFiber* fiber, Value* args,
     // return below, it would overwrite the fiber being transferred to.
     if (fiber == vm->fiber) RETURN_VAL(hasValue ? args[1] : NULL_VAL);
   }
-  
+
   if (fiber->numFrames == 0)
   {
     args[0] = wrenStringFormat(vm, "Cannot $ a finished fiber.",
                                isCall ? "call" : "transfer to");
     return PRIM_ERROR;
   }
-  
+
   if (fiber->error != NULL)
   {
     args[0] = wrenStringFormat(vm, "Cannot $ an aborted fiber.",
                                isCall ? "call" : "transfer to");
     return PRIM_ERROR;
   }
-  
+
   // When the calling fiber resumes, we'll store the result of the call in its
   // stack. If the call has two arguments (the fiber and the value), we only
   // need one slot for the result, so discard the other slot now.
@@ -340,7 +124,7 @@ static PrimitiveResult runFiber(WrenVM* vm, ObjFiber* fiber, Value* args,
   {
     *(fiber->stackTop - 1) = hasValue ? args[1] : NULL_VAL;
   }
-  
+
   return PRIM_RUN_FIBER;
 }
 
@@ -416,7 +200,7 @@ DEF_PRIMITIVE(fiber_yield)
   ObjFiber* caller = fiber->caller;
   fiber->caller = NULL;
   fiber->callerIsTrying = false;
-  
+
   // If we don't have any other pending fibers, jump all the way out of the
   // interpreter.
   if (caller == NULL)
@@ -1274,7 +1058,7 @@ static ObjClass* defineClass(WrenVM* vm, ObjModule* module, const char* name)
 void wrenInitializeCore(WrenVM* vm)
 {
   ObjModule* coreModule = wrenGetCoreModule(vm);
-  
+
   // Define the root Object class. This has to be done a little specially
   // because it has no superclass.
   vm->objectClass = defineClass(vm, coreModule, "Object");
@@ -1329,7 +1113,7 @@ void wrenInitializeCore(WrenVM* vm)
   //   '---------'   '-------------------'            -'
 
   // The rest of the classes can now be defined normally.
-  wrenInterpret(vm, "", coreLibSource);
+  wrenInterpret(vm, "", coreModuleSource);
 
   vm->boolClass = AS_CLASS(wrenFindVariable(vm, coreModule, "Bool"));
   PRIMITIVE(vm->boolClass, "toString", bool_toString);
diff --git a/src/vm/wren_core.wren.inc b/src/vm/wren_core.wren.inc
new file mode 100644
index 00000000..96ff3a16
--- /dev/null
+++ b/src/vm/wren_core.wren.inc
@@ -0,0 +1,217 @@
+// Generated automatically from builtin/core.wren. Do not edit.
+static const char* coreModuleSource =
+"class Bool {}\n"
+"class Fiber {}\n"
+"class Fn {}\n"
+"class Null {}\n"
+"class Num {}\n"
+"\n"
+"class Sequence {\n"
+"  all(f) {\n"
+"    var result = true\n"
+"    for (element in this) {\n"
+"      result = f.call(element)\n"
+"      if (!result) return result\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  any(f) {\n"
+"    var result = false\n"
+"    for (element in this) {\n"
+"      result = f.call(element)\n"
+"      if (result) return result\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  contains(element) {\n"
+"    for (item in this) {\n"
+"      if (element == item) return true\n"
+"    }\n"
+"    return false\n"
+"  }\n"
+"\n"
+"  count {\n"
+"    var result = 0\n"
+"    for (element in this) {\n"
+"      result = result + 1\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  count(f) {\n"
+"    var result = 0\n"
+"    for (element in this) {\n"
+"      if (f.call(element)) result = result + 1\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  each(f) {\n"
+"    for (element in this) {\n"
+"      f.call(element)\n"
+"    }\n"
+"  }\n"
+"\n"
+"  isEmpty { iterate(null) ? false : true }\n"
+"\n"
+"  map(transformation) { MapSequence.new(this, transformation) }\n"
+"\n"
+"  where(predicate) { WhereSequence.new(this, predicate) }\n"
+"\n"
+"  reduce(acc, f) {\n"
+"    for (element in this) {\n"
+"      acc = f.call(acc, element)\n"
+"    }\n"
+"    return acc\n"
+"  }\n"
+"\n"
+"  reduce(f) {\n"
+"    var iter = iterate(null)\n"
+"    if (!iter) Fiber.abort(\"Can't reduce an empty sequence.\")\n"
+"\n"
+"    // Seed with the first element.\n"
+"    var result = iteratorValue(iter)\n"
+"    while (iter = iterate(iter)) {\n"
+"      result = f.call(result, iteratorValue(iter))\n"
+"    }\n"
+"\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  join { join(\"\") }\n"
+"\n"
+"  join(sep) {\n"
+"    var first = true\n"
+"    var result = \"\"\n"
+"\n"
+"    for (element in this) {\n"
+"      if (!first) result = result + sep\n"
+"      first = false\n"
+"      result = result + element.toString\n"
+"    }\n"
+"\n"
+"    return result\n"
+"  }\n"
+"\n"
+"  toList {\n"
+"    var result = List.new()\n"
+"    for (element in this) {\n"
+"      result.add(element)\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"}\n"
+"\n"
+"class MapSequence is Sequence {\n"
+"  construct new(sequence, fn) {\n"
+"    _sequence = sequence\n"
+"    _fn = fn\n"
+"  }\n"
+"\n"
+"  iterate(iterator) { _sequence.iterate(iterator) }\n"
+"  iteratorValue(iterator) { _fn.call(_sequence.iteratorValue(iterator)) }\n"
+"}\n"
+"\n"
+"class WhereSequence is Sequence {\n"
+"  construct new(sequence, fn) {\n"
+"    _sequence = sequence\n"
+"    _fn = fn\n"
+"  }\n"
+"\n"
+"  iterate(iterator) {\n"
+"    while (iterator = _sequence.iterate(iterator)) {\n"
+"      if (_fn.call(_sequence.iteratorValue(iterator))) break\n"
+"    }\n"
+"    return iterator\n"
+"  }\n"
+"\n"
+"  iteratorValue(iterator) { _sequence.iteratorValue(iterator) }\n"
+"}\n"
+"\n"
+"class String is Sequence {\n"
+"  bytes { StringByteSequence.new(this) }\n"
+"  codePoints { StringCodePointSequence.new(this) }\n"
+"}\n"
+"\n"
+"class StringByteSequence is Sequence {\n"
+"  construct new(string) {\n"
+"    _string = string\n"
+"  }\n"
+"\n"
+"  [index] { _string.byteAt_(index) }\n"
+"  iterate(iterator) { _string.iterateByte_(iterator) }\n"
+"  iteratorValue(iterator) { _string.byteAt_(iterator) }\n"
+"\n"
+"  count { _string.byteCount_ }\n"
+"}\n"
+"\n"
+"class StringCodePointSequence is Sequence {\n"
+"  construct new(string) {\n"
+"    _string = string\n"
+"  }\n"
+"\n"
+"  [index] { _string.codePointAt_(index) }\n"
+"  iterate(iterator) { _string.iterate(iterator) }\n"
+"  iteratorValue(iterator) { _string.codePointAt_(iterator) }\n"
+"\n"
+"  count { _string.count }\n"
+"}\n"
+"\n"
+"class List is Sequence {\n"
+"  addAll(other) {\n"
+"    for (element in other) {\n"
+"      add(element)\n"
+"    }\n"
+"    return other\n"
+"  }\n"
+"\n"
+"  toString { \"[\" + join(\", \") + \"]\" }\n"
+"\n"
+"  +(other) {\n"
+"    var result = this[0..-1]\n"
+"    for (element in other) {\n"
+"      result.add(element)\n"
+"    }\n"
+"    return result\n"
+"  }\n"
+"}\n"
+"\n"
+"class Map {\n"
+"  keys { MapKeySequence.new(this) }\n"
+"  values { MapValueSequence.new(this) }\n"
+"\n"
+"  toString {\n"
+"    var first = true\n"
+"    var result = \"{\"\n"
+"\n"
+"    for (key in keys) {\n"
+"      if (!first) result = result + \", \"\n"
+"      first = false\n"
+"      result = result + key.toString + \": \" + this[key].toString\n"
+"    }\n"
+"\n"
+"    return result + \"}\"\n"
+"  }\n"
+"}\n"
+"\n"
+"class MapKeySequence is Sequence {\n"
+"  construct new(map) {\n"
+"    _map = map\n"
+"  }\n"
+"\n"
+"  iterate(n) { _map.iterate_(n) }\n"
+"  iteratorValue(iterator) { _map.keyIteratorValue_(iterator) }\n"
+"}\n"
+"\n"
+"class MapValueSequence is Sequence {\n"
+"  construct new(map) {\n"
+"    _map = map\n"
+"  }\n"
+"\n"
+"  iterate(n) { _map.iterate_(n) }\n"
+"  iteratorValue(iterator) { _map.valueIteratorValue_(iterator) }\n"
+"}\n"
+"\n"
+"class Range is Sequence {}\n";
diff --git a/src/vm/wren_io.c b/src/vm/wren_io.c
index e8813fce..1b0201fd 100644
--- a/src/vm/wren_io.c
+++ b/src/vm/wren_io.c
@@ -9,109 +9,7 @@
 // TODO: This is an arbitrary limit. Do something smarter.
 #define MAX_READ_LEN 1024
 
-// This string literal is generated automatically from io.wren. Do not edit.
-static const char* ioLibSource =
-"class IO {\n"
-"  static print {\n"
-"    writeString_(\"\n\")\n"
-"  }\n"
-"\n"
-"  static print(obj) {\n"
-"    writeObject_(obj)\n"
-"    writeString_(\"\n\")\n"
-"    return obj\n"
-"  }\n"
-"\n"
-"  static print(a1, a2) {\n"
-"    printAll([a1, a2])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3) {\n"
-"    printAll([a1, a2, a3])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4) {\n"
-"    printAll([a1, a2, a3, a4])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5) {\n"
-"    printAll([a1, a2, a3, a4, a5])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15])\n"
-"  }\n"
-"\n"
-"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16) {\n"
-"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16])\n"
-"  }\n"
-"\n"
-"  static printAll(sequence) {\n"
-"    for (object in sequence) writeObject_(object)\n"
-"    writeString_(\"\n\")\n"
-"  }\n"
-"\n"
-"  static write(obj) {\n"
-"    writeObject_(obj)\n"
-"    return obj\n"
-"  }\n"
-"\n"
-"  static read(prompt) {\n"
-"    if (!(prompt is String)) Fiber.abort(\"Prompt must be a string.\")\n"
-"    write(prompt)\n"
-"    return read()\n"
-"  }\n"
-"\n"
-"  static writeObject_(obj) {\n"
-"    var string = obj.toString\n"
-"    if (string is String) {\n"
-"      writeString_(string)\n"
-"    } else {\n"
-"      writeString_(\"[invalid toString]\")\n"
-"    }\n"
-"  }\n"
-"\n"
-"  foreign static writeString_(string)\n"
-"  foreign static clock\n"
-"  foreign static time\n"
-"  foreign static read()\n"
-"}\n";
+#include "wren_io.wren.inc"
 
 static void ioWriteString(WrenVM* vm)
 {
@@ -143,14 +41,14 @@ static void ioTime(WrenVM* vm)
 
 void wrenLoadIOLibrary(WrenVM* vm)
 {
-  wrenInterpret(vm, "", ioLibSource);
+  wrenInterpret(vm, "", ioModuleSource);
 }
 
 WrenForeignMethodFn wrenBindIOForeignMethod(WrenVM* vm, const char* className,
                                             const char* signature)
 {
   if (strcmp(className, "IO") != 0) return NULL;
-  
+
   if (strcmp(signature, "writeString_(_)") == 0) return ioWriteString;
   if (strcmp(signature, "clock") == 0) return ioClock;
   if (strcmp(signature, "time") == 0) return ioTime;
diff --git a/src/vm/wren_io.wren.inc b/src/vm/wren_io.wren.inc
new file mode 100644
index 00000000..d9ced63d
--- /dev/null
+++ b/src/vm/wren_io.wren.inc
@@ -0,0 +1,103 @@
+// Generated automatically from builtin/io.wren. Do not edit.
+static const char* ioModuleSource =
+"class IO {\n"
+"  static print {\n"
+"    writeString_(\"\n\")\n"
+"  }\n"
+"\n"
+"  static print(obj) {\n"
+"    writeObject_(obj)\n"
+"    writeString_(\"\n\")\n"
+"    return obj\n"
+"  }\n"
+"\n"
+"  static print(a1, a2) {\n"
+"    printAll([a1, a2])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3) {\n"
+"    printAll([a1, a2, a3])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4) {\n"
+"    printAll([a1, a2, a3, a4])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5) {\n"
+"    printAll([a1, a2, a3, a4, a5])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15])\n"
+"  }\n"
+"\n"
+"  static print(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16) {\n"
+"    printAll([a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16])\n"
+"  }\n"
+"\n"
+"  static printAll(sequence) {\n"
+"    for (object in sequence) writeObject_(object)\n"
+"    writeString_(\"\n\")\n"
+"  }\n"
+"\n"
+"  static write(obj) {\n"
+"    writeObject_(obj)\n"
+"    return obj\n"
+"  }\n"
+"\n"
+"  static read(prompt) {\n"
+"    if (!(prompt is String)) Fiber.abort(\"Prompt must be a string.\")\n"
+"    write(prompt)\n"
+"    return read()\n"
+"  }\n"
+"\n"
+"  static writeObject_(obj) {\n"
+"    var string = obj.toString\n"
+"    if (string is String) {\n"
+"      writeString_(string)\n"
+"    } else {\n"
+"      writeString_(\"[invalid toString]\")\n"
+"    }\n"
+"  }\n"
+"\n"
+"  foreign static writeString_(string)\n"
+"  foreign static clock\n"
+"  foreign static time\n"
+"  foreign static read()\n"
+"}\n";
diff --git a/src/vm/wren_meta.c b/src/vm/wren_meta.c
index 0c5d30ad..435eb22e 100644
--- a/src/vm/wren_meta.c
+++ b/src/vm/wren_meta.c
@@ -6,9 +6,7 @@
 
 #include "wren_primitive.h"
 
-// This string literal is generated automatically from meta.wren. Do not edit.
-static const char* metaLibSource =
-"class Meta {}\n";
+#include "wren_meta.wren.inc"
 
 DEF_PRIMITIVE(meta_eval)
 {
@@ -43,10 +41,10 @@ DEF_PRIMITIVE(meta_eval)
 
 void wrenLoadMetaLibrary(WrenVM* vm)
 {
-  wrenInterpret(vm, "", metaLibSource);
+  wrenInterpret(vm, "", metaModuleSource);
 
   ObjModule* coreModule = wrenGetCoreModule(vm);
-  
+
   // The methods on "Meta" are static, so get the metaclass for the Meta class.
   ObjClass* meta = AS_CLASS(wrenFindVariable(vm, coreModule, "Meta"));
   PRIMITIVE(meta->obj.classObj, "eval(_)", meta_eval);
diff --git a/src/vm/wren_meta.wren.inc b/src/vm/wren_meta.wren.inc
new file mode 100644
index 00000000..6e4e5441
--- /dev/null
+++ b/src/vm/wren_meta.wren.inc
@@ -0,0 +1,3 @@
+// Generated automatically from builtin/meta.wren. Do not edit.
+static const char* metaModuleSource =
+"class Meta {}\n";
diff --git a/src/vm/wren_vm.c b/src/vm/wren_vm.c
index 5d77958e..6aefa3ee 100644
--- a/src/vm/wren_vm.c
+++ b/src/vm/wren_vm.c
@@ -634,7 +634,7 @@ static void bindForeignClass(WrenVM* vm, ObjClass* classObj, ObjModule* module)
 // occurred.
 //
 // Returns false if the result is an error.
-static bool defineClass(WrenVM* vm, ObjFiber* fiber, int numFields,
+static bool createClass(WrenVM* vm, ObjFiber* fiber, int numFields,
                         ObjModule* module)
 {
   // Pull the name and superclass off the stack.
@@ -1195,13 +1195,13 @@ static WrenInterpretResult runInterpreter(WrenVM* vm, register ObjFiber* fiber)
 
     CASE_CODE(CLASS):
     {
-      if (!defineClass(vm, fiber, READ_BYTE(), NULL)) RUNTIME_ERROR(PEEK());
+      if (!createClass(vm, fiber, READ_BYTE(), NULL)) RUNTIME_ERROR(PEEK());
       DISPATCH();
     }
     
     CASE_CODE(FOREIGN_CLASS):
     {
-      if (!defineClass(vm, fiber, -1, fn->module)) RUNTIME_ERROR(PEEK());
+      if (!createClass(vm, fiber, -1, fn->module)) RUNTIME_ERROR(PEEK());
       DISPATCH();
     }