Fix fill_template.sh on MacOS (#188)

- closes #187
- closes #164

I just asked chatgpt to fix it and the changes seem reasonable 😬 Works
on my mac now. Haven't tested it on linux but I assume it still works
there.

Author: lucasmerlin

fill_template.sh

@@ -3,25 +3,34 @@
 set -e
 
 echo "To fill the template tell me your egui project crate name: "
-
 read crate
 
 echo "To fill the template tell me your name (for author in Cargo.toml): "
-
 read name
 
 echo "To fill the template tell me your e-mail address (also for Cargo.toml): "
-
 read email
 
 echo "Patching files..."
 
-sed -i "s/eframe_template/$crate/g" Cargo.toml
-sed -i "s/eframe_template/$crate/g" src/main.rs
-sed -i "s/eframe template/$crate/g" index.html
-sed -i "s/eframe_template/$crate/g" assets/sw.js
-sed -i "s/Emil Ernerfeldt/$name/g" Cargo.toml
-sed -i "s/emil.ernerfeldt@gmail.com/$email/g" Cargo.toml
+# Determine the correct sed syntax based on OS
+if [ "$(uname)" = "Darwin" ]; then
+  # macOS sed
+  sed_inplace() {
+    sed -i '' "$@"
+  }
+else
+  # GNU sed (Linux)
+  sed_inplace() {
+    sed -i "$@"
+  }
+fi
+
+sed_inplace "s/eframe_template/$crate/g" Cargo.toml
+sed_inplace "s/eframe_template/$crate/g" src/main.rs
+sed_inplace "s/eframe template/$crate/g" index.html
+sed_inplace "s/eframe_template/$crate/g" assets/sw.js
+sed_inplace "s/Emil Ernerfeldt/$name/g" Cargo.toml
+sed_inplace "s/emil.ernerfeldt@gmail.com/$email/g" Cargo.toml
 
 echo "Done."
-