diff --git a/Taskfile.yml b/Taskfile.yml
index d6c3e7c..2a0c2c6 100644
--- a/Taskfile.yml
+++ b/Taskfile.yml
@@ -6,9 +6,14 @@ version: 3
 
 vars:
   MOON_MODULES:
-    sh: echo ./src && find ./example -maxdepth 1 -mindepth 1 -type d
+    sh: >
+      echo ./src &&
+      find ./example -maxdepth 1 -mindepth 1 -type d
+      | grep -vE '(_build|.mooncakes)'
   EXAMPLES:
-    sh: find ./example -maxdepth 1 -mindepth 1 -type d
+    sh: >
+      find ./example -maxdepth 1 -mindepth 1 -type d
+      | grep -vE '(_build|.mooncakes)'
 
 tasks:
   release:
diff --git a/example/audio/firefly.toml b/example/audio/firefly.toml
index 7699051..ade3259 100644
--- a/example/audio/firefly.toml
+++ b/example/audio/firefly.toml
@@ -6,6 +6,7 @@ author_id = "demo"
 app_id = "moonbit-audio"
 author_name = "Demo"
 app_name = "Audio demo (MoonBit)"
+lang = "moon"
 
 [files]
-pickupCoin = { path = "assets/pickupCoin.wav"}
+pickupCoin = { path = "assets/pickupCoin.wav" }
diff --git a/example/audio/moon.mod b/example/audio/moon.mod
new file mode 100644
index 0000000..1f6f5c9
--- /dev/null
+++ b/example/audio/moon.mod
@@ -0,0 +1,7 @@
+name = "example-audio"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/audio/moon.mod.json b/example/audio/moon.mod.json
deleted file mode 100644
index edc1c21..0000000
--- a/example/audio/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-audio",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/font/firefly.toml b/example/font/firefly.toml
index 7745638..be52280 100644
--- a/example/font/firefly.toml
+++ b/example/font/firefly.toml
@@ -6,6 +6,7 @@ author_id = "demo"
 app_id = "moonbit-font"
 author_name = "Demo"
 app_name = "Font demo (MoonBit)"
+lang = "moon"
 
 [files]
 font = { path = "assets/eg_6x12.fff" }
diff --git a/example/font/moon.mod b/example/font/moon.mod
new file mode 100644
index 0000000..a35a83e
--- /dev/null
+++ b/example/font/moon.mod
@@ -0,0 +1,7 @@
+name = "example-font"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/font/moon.mod.json b/example/font/moon.mod.json
deleted file mode 100644
index 6025ef8..0000000
--- a/example/font/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-font",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/image/firefly.toml b/example/image/firefly.toml
index f0b9e8a..a9ca957 100644
--- a/example/image/firefly.toml
+++ b/example/image/firefly.toml
@@ -6,6 +6,7 @@ author_id = "demo"
 app_id = "moonbit-image"
 author_name = "Demo"
 app_name = "Image demo (MoonBit)"
+lang = "moon"
 
 [files]
 smile1 = { path = "assets/smile-1.png" }
diff --git a/example/image/moon.mod b/example/image/moon.mod
new file mode 100644
index 0000000..bf765f1
--- /dev/null
+++ b/example/image/moon.mod
@@ -0,0 +1,7 @@
+name = "example-image"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/image/moon.mod.json b/example/image/moon.mod.json
deleted file mode 100644
index a7097d6..0000000
--- a/example/image/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-image",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/input/firefly.toml b/example/input/firefly.toml
index bd1de09..7d77fd1 100644
--- a/example/input/firefly.toml
+++ b/example/input/firefly.toml
@@ -6,6 +6,7 @@ author_id = "demo"
 app_id = "moonbit-input"
 author_name = "Demo"
 app_name = "Input demo (MoonBit)"
+lang = "moon"
 
 [files]
 font = { path = "assets/eg_6x12.fff" }
diff --git a/example/input/moon.mod b/example/input/moon.mod
new file mode 100644
index 0000000..04b6b6d
--- /dev/null
+++ b/example/input/moon.mod
@@ -0,0 +1,7 @@
+name = "example-input"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/input/moon.mod.json b/example/input/moon.mod.json
deleted file mode 100644
index 9366c64..0000000
--- a/example/input/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-input",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/moon.work b/example/moon.work
new file mode 100644
index 0000000..431a1f5
--- /dev/null
+++ b/example/moon.work
@@ -0,0 +1,3 @@
+members = [
+  "..",
+]
diff --git a/example/random/firefly.toml b/example/random/firefly.toml
index d7fb565..3413c66 100644
--- a/example/random/firefly.toml
+++ b/example/random/firefly.toml
@@ -6,3 +6,4 @@ author_id = "demo"
 app_id = "moonbit-random"
 author_name = "Demo"
 app_name = "Random demo (MoonBit)"
+lang = "moon"
diff --git a/example/random/moon.mod b/example/random/moon.mod
new file mode 100644
index 0000000..7f2328d
--- /dev/null
+++ b/example/random/moon.mod
@@ -0,0 +1,7 @@
+name = "example-random"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/random/moon.mod.json b/example/random/moon.mod.json
deleted file mode 100644
index 9bff4e9..0000000
--- a/example/random/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-random",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/scores/firefly.toml b/example/scores/firefly.toml
index 106a973..3f6d666 100644
--- a/example/scores/firefly.toml
+++ b/example/scores/firefly.toml
@@ -6,6 +6,7 @@ author_id = "demo"
 app_id = "moonbit-scores"
 author_name = "Demo"
 app_name = "Scores demo (MoonBit)"
+lang = "moon"
 
 [files]
 font = { path = "assets/eg_6x10.fff" }
diff --git a/example/scores/moon.mod b/example/scores/moon.mod
new file mode 100644
index 0000000..95245b6
--- /dev/null
+++ b/example/scores/moon.mod
@@ -0,0 +1,7 @@
+name = "example-scores"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/scores/moon.mod.json b/example/scores/moon.mod.json
deleted file mode 100644
index 0f871f3..0000000
--- a/example/scores/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-scores",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/example/shapes/firefly.toml b/example/shapes/firefly.toml
index f6af6b2..71a2620 100644
--- a/example/shapes/firefly.toml
+++ b/example/shapes/firefly.toml
@@ -6,3 +6,4 @@ author_id = "demo"
 app_id = "moonbit-shapes"
 author_name = "Demo"
 app_name = "Shapes demo (MoonBit)"
+lang = "moon"
diff --git a/example/shapes/moon.mod b/example/shapes/moon.mod
new file mode 100644
index 0000000..6c1e242
--- /dev/null
+++ b/example/shapes/moon.mod
@@ -0,0 +1,7 @@
+name = "example-shapes"
+
+preferred_target = "wasm"
+
+import {
+  "firefly/firefly@0.7.0",
+}
diff --git a/example/shapes/moon.mod.json b/example/shapes/moon.mod.json
deleted file mode 100644
index 05889e6..0000000
--- a/example/shapes/moon.mod.json
+++ /dev/null
@@ -1,9 +0,0 @@
-{
-  "name": "example-shapes",
-  "deps": {
-    "firefly/firefly": {
-      "path": "../.."
-    }
-  },
-  "preferred-target": "wasm"
-}
diff --git a/moon.mod b/moon.mod
new file mode 100644
index 0000000..f65e68f
--- /dev/null
+++ b/moon.mod
@@ -0,0 +1,23 @@
+name = "firefly/firefly"
+
+version = "0.8.0"
+
+import {
+  "applejag/micromath@0.3.0",
+}
+
+readme = "README.md"
+
+repository = "https://github.com/firefly-zero/firefly-moon"
+
+license = "MIT"
+
+keywords = [ "game", "firefly-zero" ]
+
+description = "MoonBit SDK for making Firefly Zero games"
+
+preferred_target = "wasm"
+
+options(
+  source: "src",
+)
diff --git a/moon.mod.json b/moon.mod.json
deleted file mode 100644
index f6cedf3..0000000
--- a/moon.mod.json
+++ /dev/null
@@ -1,14 +0,0 @@
-{
-  "name": "firefly/firefly",
-  "version": "0.8.0",
-  "deps": {
-    "applejag/micromath": "0.3.0"
-  },
-  "readme": "README.md",
-  "repository": "https://github.com/firefly-zero/firefly-moon",
-  "license": "MIT",
-  "keywords": ["game", "firefly-zero"],
-  "description": "MoonBit SDK for making Firefly Zero games",
-  "source": "src",
-  "preferred-target": "wasm"
-}
diff --git a/src/audio/modulators.mbt b/src/audio/modulators.mbt
index 84d9d1e..0a763f9 100644
--- a/src/audio/modulators.mbt
+++ b/src/audio/modulators.mbt
@@ -1,6 +1,6 @@
 ///|
 pub trait Modulator {
-  modulate(Self, node_id : UInt, param : UInt) -> Unit
+  fn modulate(Self, node_id : UInt, param : UInt) -> Unit
 }
 
 ///|
@@ -20,7 +20,7 @@ pub(all) struct LinearModulator {
 
 ///|
 #inline
-pub impl Modulator for LinearModulator with modulate(
+pub impl Modulator for LinearModulator with fn modulate(
   self : LinearModulator,
   node_id : UInt,
   param : UInt,
@@ -51,7 +51,7 @@ pub(all) struct HoldModulator {
 
 ///|
 #inline
-pub impl Modulator for HoldModulator with modulate(
+pub impl Modulator for HoldModulator with fn modulate(
   self : HoldModulator,
   node_id : UInt,
   param : UInt,
@@ -74,7 +74,7 @@ pub(all) struct SineModulator {
 
 ///|
 #inline
-pub impl Modulator for SineModulator with modulate(
+pub impl Modulator for SineModulator with fn modulate(
   self : SineModulator,
   node_id : UInt,
   param : UInt,
diff --git a/src/audio/node.mbt b/src/audio/node.mbt
index ccd42d4..6430c46 100644
--- a/src/audio/node.mbt
+++ b/src/audio/node.mbt
@@ -6,7 +6,7 @@ struct Node {
 
 ///|
 pub trait Marker {
-  next(Self) -> Node
+  fn next(Self) -> Node
 }
 
 ///|
@@ -20,7 +20,7 @@ pub struct Sine(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Sine with next(self : Sine) -> Node {
+pub impl Marker for Sine with fn next(self : Sine) -> Node {
   self.0
 }
 
@@ -31,7 +31,7 @@ struct Mix(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Mix with next(self : Mix) -> Node {
+pub impl Marker for Mix with fn next(self : Mix) -> Node {
   self.0
 }
 
@@ -42,7 +42,7 @@ struct AllForOne(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for AllForOne with next(self : AllForOne) -> Node {
+pub impl Marker for AllForOne with fn next(self : AllForOne) -> Node {
   self.0
 }
 
@@ -53,7 +53,7 @@ struct Gain(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Gain with next(self : Gain) -> Node {
+pub impl Marker for Gain with fn next(self : Gain) -> Node {
   self.0
 }
 
@@ -64,7 +64,7 @@ struct Loop(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Loop with next(self : Loop) -> Node {
+pub impl Marker for Loop with fn next(self : Loop) -> Node {
   self.0
 }
 
@@ -75,7 +75,7 @@ struct Concat(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Concat with next(self : Concat) -> Node {
+pub impl Marker for Concat with fn next(self : Concat) -> Node {
   self.0
 }
 
@@ -86,7 +86,7 @@ struct Pan(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Pan with next(self : Pan) -> Node {
+pub impl Marker for Pan with fn next(self : Pan) -> Node {
   self.0
 }
 
@@ -97,7 +97,7 @@ struct Mute(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Mute with next(self : Mute) -> Node {
+pub impl Marker for Mute with fn next(self : Mute) -> Node {
   self.0
 }
 
@@ -108,7 +108,7 @@ struct Pause(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Pause with next(self : Pause) -> Node {
+pub impl Marker for Pause with fn next(self : Pause) -> Node {
   self.0
 }
 
@@ -119,7 +119,7 @@ struct TrackPosition(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for TrackPosition with next(self : TrackPosition) -> Node {
+pub impl Marker for TrackPosition with fn next(self : TrackPosition) -> Node {
   self.0
 }
 
@@ -130,7 +130,7 @@ struct LowPass(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for LowPass with next(self : LowPass) -> Node {
+pub impl Marker for LowPass with fn next(self : LowPass) -> Node {
   self.0
 }
 
@@ -141,7 +141,7 @@ struct HighPass(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for HighPass with next(self : HighPass) -> Node {
+pub impl Marker for HighPass with fn next(self : HighPass) -> Node {
   self.0
 }
 
@@ -152,7 +152,7 @@ struct TakeLeft(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for TakeLeft with next(self : TakeLeft) -> Node {
+pub impl Marker for TakeLeft with fn next(self : TakeLeft) -> Node {
   self.0
 }
 
@@ -163,7 +163,7 @@ struct TakeRight(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for TakeRight with next(self : TakeRight) -> Node {
+pub impl Marker for TakeRight with fn next(self : TakeRight) -> Node {
   self.0
 }
 
@@ -174,7 +174,7 @@ struct Swap(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Swap with next(self : Swap) -> Node {
+pub impl Marker for Swap with fn next(self : Swap) -> Node {
   self.0
 }
 
@@ -185,7 +185,7 @@ struct Clip(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Clip with next(self : Clip) -> Node {
+pub impl Marker for Clip with fn next(self : Clip) -> Node {
   self.0
 }
 
@@ -196,7 +196,7 @@ struct Square(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Square with next(self : Square) -> Node {
+pub impl Marker for Square with fn next(self : Square) -> Node {
   self.0
 }
 
@@ -207,7 +207,7 @@ struct Sawtooth(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Sawtooth with next(self : Sawtooth) -> Node {
+pub impl Marker for Sawtooth with fn next(self : Sawtooth) -> Node {
   self.0
 }
 
@@ -218,7 +218,7 @@ struct Triangle(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Triangle with next(self : Triangle) -> Node {
+pub impl Marker for Triangle with fn next(self : Triangle) -> Node {
   self.0
 }
 
@@ -229,7 +229,7 @@ struct Noise(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Noise with next(self : Noise) -> Node {
+pub impl Marker for Noise with fn next(self : Noise) -> Node {
   self.0
 }
 
@@ -240,7 +240,7 @@ struct Empty(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Empty with next(self : Empty) -> Node {
+pub impl Marker for Empty with fn next(self : Empty) -> Node {
   self.0
 }
 
@@ -251,7 +251,7 @@ struct Zero(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for Zero with next(self : Zero) -> Node {
+pub impl Marker for Zero with fn next(self : Zero) -> Node {
   self.0
 }
 
@@ -262,7 +262,7 @@ struct File(Node)
 ///|
 /// Get the next node for applying more effects.
 #inline
-pub impl Marker for File with next(self : File) -> Node {
+pub impl Marker for File with fn next(self : File) -> Node {
   self.0
 }
 
diff --git a/src/graphics_angle.mbt b/src/graphics_angle.mbt
index 2c02a08..1cad8e7 100644
--- a/src/graphics_angle.mbt
+++ b/src/graphics_angle.mbt
@@ -3,7 +3,7 @@
 struct Angle(Float) derive(Debug, Eq, Compare, Hash, Default)
 
 ///|
-pub impl Show for Angle with output(self : Angle, logger : &Logger) -> Unit {
+pub impl Show for Angle with fn output(self : Angle, logger : &Logger) -> Unit {
   self.to_deg().to_int().output(logger)
   logger.write_char('°')
 }
@@ -76,31 +76,31 @@ test "angle to degrees" {
 
 ///|
 /// Add together two angles.
-pub impl Add for Angle with add(self : Angle, other : Angle) -> Angle {
+pub impl Add for Angle with fn add(self : Angle, other : Angle) -> Angle {
   self.0 + other.0
 }
 
 ///|
 /// Subtract one angle from another.
-pub impl Sub for Angle with sub(self : Angle, other : Angle) -> Angle {
+pub impl Sub for Angle with fn sub(self : Angle, other : Angle) -> Angle {
   self.0 - other.0
 }
 
 ///|
 /// Multiply one angle with another.
-pub impl Mul for Angle with mul(self : Angle, other : Angle) -> Angle {
+pub impl Mul for Angle with fn mul(self : Angle, other : Angle) -> Angle {
   self.0 * other.0
 }
 
 ///|
 /// Divide one angle with another.
-pub impl Div for Angle with div(self : Angle, other : Angle) -> Angle {
+pub impl Div for Angle with fn div(self : Angle, other : Angle) -> Angle {
   self.0 / other.0
 }
 
 ///|
 /// Negate an angle
-pub impl Neg for Angle with neg(self : Angle) -> Angle {
+pub impl Neg for Angle with fn neg(self : Angle) -> Angle {
   -self.0
 }
 
diff --git a/src/graphics_color.mbt b/src/graphics_color.mbt
index 59207b4..3870cbf 100644
--- a/src/graphics_color.mbt
+++ b/src/graphics_color.mbt
@@ -37,12 +37,12 @@ pub(all) enum Color {
 } derive(Debug, Eq, Compare, Hash)
 
 ///|
-pub impl Show for Color with output(self : Color, logger : &Logger) -> Unit {
+pub impl Show for Color with fn output(self : Color, logger : &Logger) -> Unit {
   logger.write_string(self.to_string())
 }
 
 ///|
-pub impl Show for Color with to_string(self : Color) -> String {
+pub impl Show for Color with fn to_string(self : Color) -> String {
   match self {
     None => "none"
     Black => "black"
@@ -65,7 +65,7 @@ pub impl Show for Color with to_string(self : Color) -> String {
 }
 
 ///|
-pub impl Default for Color with default() -> Color {
+pub impl Default for Color with fn default() -> Color {
   Color::None
 }
 
diff --git a/src/graphics_point.mbt b/src/graphics_point.mbt
index 08d99f6..db6f779 100644
--- a/src/graphics_point.mbt
+++ b/src/graphics_point.mbt
@@ -138,19 +138,19 @@ pub fn Point::abs(self : Point) -> Point {
 
 ///|
 /// Add together two points.
-pub impl Add for Point with add(self : Point, other : Point) -> Point {
+pub impl Add for Point with fn add(self : Point, other : Point) -> Point {
   { x: self.x + other.x, y: self.y + other.y }
 }
 
 ///|
 /// Subtract one point from another.
-pub impl Sub for Point with sub(self : Point, other : Point) -> Point {
+pub impl Sub for Point with fn sub(self : Point, other : Point) -> Point {
   { x: self.x - other.x, y: self.y - other.y }
 }
 
 ///|
 /// Negate a Point.
-pub impl Neg for Point with neg(self : Point) -> Point {
+pub impl Neg for Point with fn neg(self : Point) -> Point {
   { x: -self.x, y: -self.y }
 }
 
diff --git a/src/graphics_size.mbt b/src/graphics_size.mbt
index fe0074e..8de467e 100644
--- a/src/graphics_size.mbt
+++ b/src/graphics_size.mbt
@@ -107,12 +107,12 @@ test "Size.component_max" {
 
 ///|
 /// Add together two sizes.
-pub impl Add for Size with add(self : Size, other : Size) -> Size {
+pub impl Add for Size with fn add(self : Size, other : Size) -> Size {
   { w: self.w + other.w, h: self.h + other.h }
 }
 
 ///|
 /// Subtract one size from another.
-pub impl Sub for Size with sub(self : Size, other : Size) -> Size {
+pub impl Sub for Size with fn sub(self : Size, other : Size) -> Size {
   { w: self.w - other.w, h: self.h - other.h }
 }
diff --git a/src/input_pad.mbt b/src/input_pad.mbt
index 4b03c2e..163c6dd 100644
--- a/src/input_pad.mbt
+++ b/src/input_pad.mbt
@@ -149,18 +149,18 @@ pub fn Pad::abs(self : Pad) -> Pad {
 
 ///|
 /// Add together two Pads.
-pub impl Add for Pad with add(self : Pad, other : Pad) -> Pad {
+pub impl Add for Pad with fn add(self : Pad, other : Pad) -> Pad {
   { x: self.x + other.x, y: self.y + other.y }
 }
 
 ///|
 /// Subtract one Pad from another.
-pub impl Sub for Pad with sub(self : Pad, other : Pad) -> Pad {
+pub impl Sub for Pad with fn sub(self : Pad, other : Pad) -> Pad {
   { x: self.x - other.x, y: self.y - other.y }
 }
 
 ///|
 /// Negate a Pad.
-pub impl Neg for Pad with neg(self : Pad) -> Pad {
+pub impl Neg for Pad with fn neg(self : Pad) -> Pad {
   { x: -self.x, y: -self.y }
 }
diff --git a/src/misc_language.mbt b/src/misc_language.mbt
index 517f797..a4ad7ab 100644
--- a/src/misc_language.mbt
+++ b/src/misc_language.mbt
@@ -29,7 +29,7 @@ pub(all) enum Language {
 } derive(Debug, Eq, Hash)
 
 ///|
-pub impl Default for Language with default() -> Language {
+pub impl Default for Language with fn default() -> Language {
   Language::English
 }
 
diff --git a/src/misc_theme.mbt b/src/misc_theme.mbt
index e6138b7..72b10a1 100644
--- a/src/misc_theme.mbt
+++ b/src/misc_theme.mbt
@@ -13,7 +13,7 @@ pub(all) struct Theme {
 } derive(Debug, Eq)
 
 ///|
-pub impl Default for Theme with default() -> Theme {
+pub impl Default for Theme with fn default() -> Theme {
   Theme::{
     id: 0,
     primary: Color::Black,
diff --git a/src/net.mbt b/src/net.mbt
index f20f429..fa7ec1f 100644
--- a/src/net.mbt
+++ b/src/net.mbt
@@ -1,7 +1,7 @@
 ///|
 /// A peer obtained either from `Peers` (`get_peers`) or from `get_me`.
 pub trait AnyPeer {
-  to_int(self : Self) -> Int
+  fn to_int(self : Self) -> Int
 }
 
 ///|
@@ -17,7 +17,7 @@ struct Me {
 } derive(Hash)
 
 ///|
-pub impl AnyPeer for Me with to_int(self : Me) -> Int {
+pub impl AnyPeer for Me with fn to_int(self : Me) -> Int {
   self.raw
 }
 
@@ -35,12 +35,12 @@ struct Peer {
 } derive(Eq, Compare, Hash)
 
 ///|
-pub impl AnyPeer for Peer with to_int(self : Peer) -> Int {
+pub impl AnyPeer for Peer with fn to_int(self : Peer) -> Int {
   self.raw
 }
 
 ///|
-pub impl Show for Peer with to_string(self) -> String {
+pub impl Show for Peer with fn to_string(self) -> String {
   match self.raw {
     0xFF => "Peer(*)"
     _ => "Peer(\{self.raw})"
@@ -48,7 +48,7 @@ pub impl Show for Peer with to_string(self) -> String {
 }
 
 ///|
-pub impl Show for Peer with output(self, logger : &Logger) -> Unit {
+pub impl Show for Peer with fn output(self, logger : &Logger) -> Unit {
   match self.raw {
     0xFF => logger.write_string("Peer(*)")
     _ => {
@@ -70,7 +70,7 @@ pub fn Peer::combined() -> Peer {
 ///|
 /// `Peer` type default value, which is `Peer::combined`.
 #inline
-pub impl Default for Peer with default() -> Peer {
+pub impl Default for Peer with fn default() -> Peer {
   Peer::combined()
 }
 
diff --git a/src/shapes/arc.mbt b/src/shapes/arc.mbt
index 2f87d4e..fbf2991 100644
--- a/src/shapes/arc.mbt
+++ b/src/shapes/arc.mbt
@@ -11,7 +11,7 @@ pub(all) struct Arc {
 ///|
 /// Draw this arc to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Arc with draw(self : Arc) -> Unit {
+pub impl Shape for Arc with fn draw(self : Arc) -> Unit {
   @firefly.draw_arc(
     self.point,
     self.diameter,
diff --git a/src/shapes/circle.mbt b/src/shapes/circle.mbt
index 1e8ab6c..3837787 100644
--- a/src/shapes/circle.mbt
+++ b/src/shapes/circle.mbt
@@ -9,7 +9,7 @@ pub(all) struct Circle {
 ///|
 /// Draw this circle to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Circle with draw(self : Circle) -> Unit {
+pub impl Shape for Circle with fn draw(self : Circle) -> Unit {
   @firefly.draw_circle(self.point, self.diameter, self.style)
 }
 
diff --git a/src/shapes/ellipse.mbt b/src/shapes/ellipse.mbt
index 973487c..ca07175 100644
--- a/src/shapes/ellipse.mbt
+++ b/src/shapes/ellipse.mbt
@@ -9,7 +9,7 @@ pub(all) struct Ellipse {
 ///|
 /// Draw this ellipse to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Ellipse with draw(self : Ellipse) -> Unit {
+pub impl Shape for Ellipse with fn draw(self : Ellipse) -> Unit {
   @firefly.draw_ellipse(self.point, self.size, self.style)
 }
 
diff --git a/src/shapes/line.mbt b/src/shapes/line.mbt
index 001d855..471aa7b 100644
--- a/src/shapes/line.mbt
+++ b/src/shapes/line.mbt
@@ -9,6 +9,6 @@ pub(all) struct Line {
 ///|
 /// Draw this line to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Line with draw(self : Line) -> Unit {
+pub impl Shape for Line with fn draw(self : Line) -> Unit {
   @firefly.draw_line(self.a, self.b, self.style)
 }
diff --git a/src/shapes/rect.mbt b/src/shapes/rect.mbt
index f70ae23..ba6175d 100644
--- a/src/shapes/rect.mbt
+++ b/src/shapes/rect.mbt
@@ -9,7 +9,7 @@ pub(all) struct Rect {
 ///|
 /// Draw this rectangle to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Rect with draw(self : Rect) -> Unit {
+pub impl Shape for Rect with fn draw(self : Rect) -> Unit {
   @firefly.draw_rect(self.point, self.size, self.style)
 }
 
diff --git a/src/shapes/rounded_rect.mbt b/src/shapes/rounded_rect.mbt
index 46bef2e..05bfef7 100644
--- a/src/shapes/rounded_rect.mbt
+++ b/src/shapes/rounded_rect.mbt
@@ -10,7 +10,7 @@ pub(all) struct RoundedRect {
 ///|
 /// Draw this rounded rectangle to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for RoundedRect with draw(self : RoundedRect) -> Unit {
+pub impl Shape for RoundedRect with fn draw(self : RoundedRect) -> Unit {
   @firefly.draw_rounded_rect(self.point, self.size, self.corner, self.style)
 }
 
diff --git a/src/shapes/sector.mbt b/src/shapes/sector.mbt
index 61cdc31..6702c84 100644
--- a/src/shapes/sector.mbt
+++ b/src/shapes/sector.mbt
@@ -11,7 +11,7 @@ pub(all) struct Sector {
 ///|
 /// Draw this circle sector to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Sector with draw(self : Sector) -> Unit {
+pub impl Shape for Sector with fn draw(self : Sector) -> Unit {
   @firefly.draw_sector(
     self.point,
     self.diameter,
diff --git a/src/shapes/top.mbt b/src/shapes/top.mbt
index c6fa325..43e9520 100644
--- a/src/shapes/top.mbt
+++ b/src/shapes/top.mbt
@@ -5,5 +5,5 @@ using @firefly {type Angle, type LineStyle, type Point, type Size, type Style}
 /// Trait for shapes that can draw to the screen.
 pub trait Shape {
   /// Draw this shape to the screen (or the current canvas, if one is set).
-  draw(Self) -> Unit
+  fn draw(Self) -> Unit
 }
diff --git a/src/shapes/triangle.mbt b/src/shapes/triangle.mbt
index 045425c..d9046bf 100644
--- a/src/shapes/triangle.mbt
+++ b/src/shapes/triangle.mbt
@@ -10,6 +10,6 @@ pub(all) struct Triangle {
 ///|
 /// Draw this triangle to the screen (or the current canvas, if one is set).
 #inline
-pub impl Shape for Triangle with draw(self : Triangle) -> Unit {
+pub impl Shape for Triangle with fn draw(self : Triangle) -> Unit {
   @firefly.draw_triangle(self.a, self.b, self.c, self.style)
 }