Add multiple-bridge-modules example (#302)

This commit introduces an example of using multiple bridge modules in a
project.

Cargo.toml

@@ -38,6 +38,7 @@ members = [
 
   "examples/async-functions",
   "examples/codegen-visualizer",
+  "examples/multiple-bridge-modules",
   "examples/rust-binary-calls-swift-package",
   "examples/without-a-bridge-module",
 ]

examples/multiple-bridge-modules/.gitignore

@@ -0,0 +1,2 @@
+main
+generated

examples/multiple-bridge-modules/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "multiple-bridge-modules"
+version = "0.1.0"
+edition = "2021"
+publish = []
+
+build = "build.rs"
+
+[lib]
+crate-type = ["staticlib"]
+
+[build-dependencies]
+swift-bridge-build = { path = "../../crates/swift-bridge-build" }
+
+[dependencies]
+swift-bridge = { path = "../../" }

examples/multiple-bridge-modules/README.md

@@ -0,0 +1,17 @@
+# Multiple Bridge Modules
+
+`swift-bridge` supports defining multiple bridge modules across one or more files.
+
+This example demonstrates how to define and generate code for multiple bridge modules.
+
+The Rust crate contains a `crate::bridge::user` and a `crate::bridge::bank` module.
+
+Each module contains a bridge module that exposes types to `Swift`.
+
+The `main.swift` function uses these bridged types to create and print some information.
+
+## To Run
+
+```sh
+./run.sh
+```

examples/multiple-bridge-modules/bridging-header.h

@@ -0,0 +1,7 @@
+#ifndef BridgingHeader_h
+#define BridgingHeader_h
+
+#include "./generated/SwiftBridgeCore.h"
+#include "./generated/multiple-bridge-modules/multiple-bridge-modules.h"
+
+#endif

examples/multiple-bridge-modules/build.rs

@@ -0,0 +1,13 @@
+use std::path::PathBuf;
+
+fn main() {
+    let out_dir = PathBuf::from("./generated");
+
+    let bridges = vec!["src/bridge/bank.rs", "src/bridge/user.rs"];
+    for path in &bridges {
+        println!("cargo:rerun-if-changed={}", path);
+    }
+
+    swift_bridge_build::parse_bridges(bridges)
+        .write_all_concatenated(out_dir, env!("CARGO_PKG_NAME"));
+}

examples/multiple-bridge-modules/main.swift

@@ -0,0 +1,10 @@
+func print_bank_account_amount(bank_account: BankAccount) {
+    print("Bank Account contains $\(bank_account.amount())")
+}
+
+func print_user_name(user: User) {
+    print("User Name \(user.name().toString())")
+}
+
+print_bank_account_amount(bank_account: make_bank_account())
+print_user_name(user: make_user())

examples/multiple-bridge-modules/run.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+THISDIR=$(dirname $0)
+cd $THISDIR
+
+cargo build -p multiple-bridge-modules
+
+swiftc -L ../../target/debug \
+  -lmultiple_bridge_modules \
+  -import-objc-header bridging-header.h \
+  -framework CoreFoundation -framework SystemConfiguration \
+  main.swift ./generated/SwiftBridgeCore.swift ./generated/multiple-bridge-modules/multiple-bridge-modules.swift
+
+./main

examples/multiple-bridge-modules/src/bridge.rs

@@ -0,0 +1,5 @@
+//! The `build.rs` script parses both of the child modules and generates the corresponding
+//! Swift and C code.
+
+pub(crate) mod bank;
+pub(crate) mod user;

examples/multiple-bridge-modules/src/bridge/bank.rs

@@ -0,0 +1,19 @@
+#[swift_bridge::bridge]
+mod ffi {
+    extern "Rust" {
+        type BankAccount;
+
+        #[swift_bridge(get(amount))]
+        fn amount(&self) -> u32;
+
+        fn make_bank_account() -> BankAccount;
+    }
+}
+
+pub(crate) struct BankAccount {
+    pub amount: u32,
+}
+
+fn make_bank_account() -> BankAccount {
+    BankAccount { amount: 500 }
+}

examples/multiple-bridge-modules/src/bridge/user.rs

@@ -0,0 +1,22 @@
+#[swift_bridge::bridge]
+mod ffi {
+    extern "Rust" {
+        type User;
+
+        #[swift_bridge(get(&name))]
+        fn name(&self) -> &str;
+
+        fn make_user() -> User;
+    }
+}
+
+struct User {
+    #[allow(dead_code)]
+    name: String,
+}
+
+fn make_user() -> User {
+    User {
+        name: "Bob".to_string(),
+    }
+}

examples/multiple-bridge-modules/src/lib.rs

@@ -0,0 +1 @@
+mod bridge;

examples/without-a-bridge-module/README.md

@@ -16,3 +16,9 @@ pub struct User {
     name: String
 }
 ```
+
+## To Run
+
+```sh
+./run.sh
+```