Add SwiftUI demo

crates/cli/tests/cli_run.rs

@@ -297,7 +297,7 @@ mod cli_run {
                     let file_name = example_file(dir_name, example.filename);
 
                     match example.executable_filename {
-                        "form" | "hello-gui" | "breakout" | "ruby" => {
+                        "form" | "hello-gui" | "breakout" | "ruby" | "swiftui" => {
                             // Since these require things the build system often doesn't have
                             // (e.g. GUIs open a window, Ruby needs ruby installed, WASM needs a browser)
                             // we do `roc build` on them but don't run them.
@@ -548,6 +548,14 @@ mod cli_run {
                 use_valgrind: false,
             }
         },
+        swiftui:"swiftui" => Example {
+            filename: "main.roc",
+            executable_filename: "swiftui",
+            stdin: &[],
+            input_file: None,
+            expected_ending: "",
+            use_valgrind: false,
+        },
     }
 
     macro_rules! benchmarks {

crates/compiler/build/src/link.rs

@@ -423,6 +423,7 @@ pub fn build_c_host_native(
     command.output().unwrap()
 }
 
+#[allow(clippy::too_many_arguments)]
 pub fn build_swift_host_native(
     env_path: &str,
     env_home: &str,
@@ -431,16 +432,25 @@ pub fn build_swift_host_native(
     opt_level: OptLevel,
     shared_lib_path: Option<&Path>,
     objc_header_path: Option<&str>,
+    arch: Architecture,
 ) -> Output {
     if shared_lib_path.is_some() {
         unimplemented!("Linking a shared library to Swift not yet implemented");
     }
 
-    let mut command = Command::new("xcrun"); // xcrun helps swiftc to find the right header files
+    let mut command = Command::new("arch");
     command
         .env_clear()
         .env("PATH", &env_path)
-        .env("HOME", &env_home)
+        .env("HOME", &env_home);
+
+    match arch {
+        Architecture::Aarch64(_) => command.arg("-arm64"),
+        _ => command.arg(format!("-{}", arch)),
+    };
+
+    command
+        .arg("xcrun") // xcrun helps swiftc to find the right header files
         .arg("swiftc")
         .args(sources)
         .arg("-emit-object")
@@ -734,6 +744,7 @@ pub fn rebuild_host(
             swift_host_header_src
                 .exists()
                 .then(|| swift_host_header_src.to_str().unwrap()),
+            target.architecture,
         );
         validate_output("host.swift", "swiftc", output);
     }

examples/swiftui/main.roc

@@ -0,0 +1,6 @@
+app "swiftui"
+    packages { pf: "platform/main.roc" }
+    imports []
+    provides [main] to pf
+
+main = "Roc <3 Swift!\n"

examples/swiftui/platform/host.h

@@ -0,0 +1,9 @@
+#include <stdlib.h>
+
+struct RocStr {
+    char* bytes;
+    size_t len;
+    size_t capacity;
+};
+
+extern void roc__mainForHost_1_exposed_generic(const struct RocStr *data);

examples/swiftui/platform/host.swift

@@ -0,0 +1,78 @@
+import Foundation
+import SwiftUI
+
+@_cdecl("roc_alloc")
+func rocAlloc(size: Int, _alignment: UInt) -> UInt  {
+    guard let ptr = malloc(size) else {
+        return 0
+    }
+    return UInt(bitPattern: ptr)
+}
+
+@_cdecl("roc_dealloc")
+func rocDealloc(ptr: UInt, _alignment: UInt)  {
+    free(UnsafeMutableRawPointer(bitPattern: ptr))
+}
+
+@_cdecl("roc_realloc")
+func rocRealloc(ptr: UInt, _oldSize: Int, newSize: Int, _alignment: UInt) -> UInt {
+    guard let ptr = realloc(UnsafeMutableRawPointer(bitPattern: ptr), newSize) else {
+        return 0
+    }
+    return UInt(bitPattern: ptr)
+}
+
+func isSmallString(rocStr: RocStr) -> Bool {
+    return rocStr.capacity < 0
+}
+
+func getStrLen(rocStr: RocStr) -> Int {
+    if isSmallString(rocStr: rocStr) {
+        // Small String length is last in the byte of capacity.
+        var cap = rocStr.capacity
+        let count = MemoryLayout.size(ofValue: cap)
+        let bytes = Data(bytes: &cap, count: count)
+        let lastByte = bytes[count - 1]
+        return Int(lastByte ^ 0b1000_0000)
+    } else {
+        return rocStr.len
+    }
+}
+
+func getSwiftString(rocStr: RocStr) -> String {
+    let length = getStrLen(rocStr: rocStr)
+    
+    if isSmallString(rocStr: rocStr) {
+        let data: Data = withUnsafePointer(to: rocStr) { ptr in
+            Data(bytes: ptr, count: length)
+        }
+        return String(data: data, encoding: .utf8)!
+    } else {
+        let data = Data(bytes: rocStr.bytes, count: length)
+        return String(data: data, encoding: .utf8)!
+    }
+}
+
+struct ContentView: View {
+    var str: String
+    
+    init() {
+        var rocStr = RocStr()
+        roc__mainForHost_1_exposed_generic(&rocStr)
+        self.str = getSwiftString(rocStr: rocStr)
+    }
+
+    var body: some View {
+        Text(self.str)
+            .padding()
+    }
+}
+
+@main
+struct RocTestApp: App {
+    var body: some Scene {
+        WindowGroup {
+            ContentView()
+        }
+    }
+}

examples/swiftui/platform/main.roc

@@ -0,0 +1,9 @@
+platform "swiftui-platform"
+    requires {} { main : Str }
+    exposes []
+    packages {}
+    imports []
+    provides [mainForHost]
+
+mainForHost : Str
+mainForHost = main

examples/swiftui/run.sh

@@ -0,0 +1,6 @@
+#! /usr/bin/env bash
+
+cargo run -- build
+mkdir -p SwiftUIDemo.app/Contents/MacOS/
+mv swiftui SwiftUIDemo.app/Contents/MacOS/SwiftUIDemo
+open SwiftUIDemo.app