From 67903e6b5752ad2f38282a973c604c4c5b85cbfa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nh=C3=A2n?= <hi@imnhan.com>
Date: Sun, 17 Sep 2023 11:23:52 +0700
Subject: [PATCH] use `must`

---
 main.go      | 25 +++++++------------------
 must/must.go | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 18 deletions(-)
 create mode 100644 must/must.go

diff --git a/main.go b/main.go
index d03848e..51dcdf5 100644
--- a/main.go
+++ b/main.go
@@ -6,13 +6,13 @@ import (
 	"flag"
 	"image"
 	_ "image/png"
-	"log"
 	"math/rand"
 	"time"
 
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
+	"go.imnhan.com/shark/must"
 )
 
 const SPRITE_X = 100
@@ -221,15 +221,12 @@ func (g *Game) Layout(outsideWidth, outsideHeight int) (w, h int) {
 }
 
 func NewAnim(sprites embed.FS, subdir string) *Anim {
-	files, err := sprites.ReadDir("sprites/" + subdir)
-	PanicIfErr(err)
+	files := must.One(sprites.ReadDir("sprites/" + subdir))
 	var frames []*ebiten.Image
 	for _, direntry := range files {
 		fname := direntry.Name()
-		frame, err := sprites.ReadFile("sprites/" + subdir + "/" + fname)
-		PanicIfErr(err)
-		img, _, err := ebitenutil.NewImageFromReader(bytes.NewReader(frame))
-		PanicIfErr(err)
+		frame := must.One(sprites.ReadFile("sprites/" + subdir + "/" + fname))
+		img, _ := must.Two(ebitenutil.NewImageFromReader(bytes.NewReader(frame)))
 		frames = append(frames, img)
 	}
 	return &Anim{frames}
@@ -284,19 +281,11 @@ func main() {
 	ebiten.SetWindowDecorated(false)
 	ebiten.SetWindowFloating(true)
 
-	AppIcon, _, iconerr := image.Decode(bytes.NewReader(IconFile))
-	PanicIfErr(iconerr)
+	AppIcon, _ := must.Two(image.Decode(bytes.NewReader(IconFile)))
 	ebiten.SetWindowIcon([]image.Image{AppIcon})
 
-	err := ebiten.RunGameWithOptions(
+	must.Zero(ebiten.RunGameWithOptions(
 		&game,
 		&ebiten.RunGameOptions{ScreenTransparent: true},
-	)
-	PanicIfErr(err)
-}
-
-func PanicIfErr(err error) {
-	if err != nil {
-		log.Fatal(err)
-	}
+	))
 }
diff --git a/must/must.go b/must/must.go
new file mode 100644
index 0000000..6fc1354
--- /dev/null
+++ b/must/must.go
@@ -0,0 +1,34 @@
+// A.k.a "I just wanna write python"
+// Good for irrecoverable cases we absolutely want to fail fast with a
+// stacktrace.
+// Possibly useful for quick prototyping too, but ofc please treat every usage
+// of this package as a FIXME item and clean it up before running in
+// production.
+package must
+
+func Zero(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func One[T any](val T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return val
+}
+
+func Two[T any, U any](v1 T, v2 U, err error) (T, U) {
+	if err != nil {
+		panic(err)
+	}
+	return v1, v2
+}
+
+func Ok[T any](v T, ok bool) T {
+	if !ok {
+		panic("not ok")
+	}
+	return v
+}