Merge pull request #488 from stepchowfun/pattern-matching-example

Demonstrate how to construct and eliminate choices

README.md

@@ -223,7 +223,7 @@ The code generated for choices supports case analysis, so clients can take diffe
 fn handle_response(response: SendEmailResponseIn) {
     match response {
         Success => println!("The email was sent!"),
-        Error(message) => println!("An error occurred: {}", message),
+        Error(message) => println!("An error occurred: {message}"),
     }
 }
 ```

examples/rust/src/main.rs

@@ -6,37 +6,54 @@ use {
         io::{self, BufReader, BufWriter},
     },
     types::{
-        types::{SendEmailRequestIn, SendEmailRequestOut},
+        types::{
+            SendEmailRequestIn, SendEmailRequestOut, SendEmailResponseIn, SendEmailResponseOut,
+        },
         Deserialize, Serialize,
     },
 };
 
-const FILE_PATH: &str = "/tmp/message";
+const REQUEST_FILE_PATH: &str = "/tmp/request";
+const RESPONSE_FILE_PATH: &str = "/tmp/response";
 
 fn write_to_file() -> io::Result<()> {
-    let message = SendEmailRequestOut {
+    let request_message = SendEmailRequestOut {
         to: "[email protected]".to_owned(),
         subject: "I love Typical!".to_owned(),
         body: "It makes serialization easy and safe.".to_owned(),
     };
 
-    let file = BufWriter::new(File::create(FILE_PATH)?);
-    message.serialize(file)
+    let response_message = SendEmailResponseOut::Error("Example error".to_string());
+
+    let request_file = BufWriter::new(File::create(REQUEST_FILE_PATH)?);
+    request_message.serialize(request_file)?;
+
+    let response_file = BufWriter::new(File::create(RESPONSE_FILE_PATH)?);
+    response_message.serialize(response_file)
 }
 
 fn read_from_file() -> io::Result<()> {
-    let file = BufReader::new(File::open(FILE_PATH)?);
-    let message = SendEmailRequestIn::deserialize(file)?;
+    let request_file = BufReader::new(File::open(REQUEST_FILE_PATH)?);
+    let request_message = SendEmailRequestIn::deserialize(request_file)?;
+
+    let response_file = BufReader::new(File::open(RESPONSE_FILE_PATH)?);
+    let response_message = SendEmailResponseIn::deserialize(response_file)?;
+
+    println!("to: {}", request_message.to);
+    println!("subject: {}", request_message.subject);
+    println!("body: {}", request_message.body);
 
-    println!("to: {}", message.to);
-    println!("subject: {}", message.subject);
-    println!("body: {}", message.body);
+    match response_message {
+        SendEmailResponseIn::Success => println!("The email was sent!"),
+        SendEmailResponseIn::Error(message) => println!("An error occurred: {message}"),
+    }
 
     Ok(())
 }
 
 fn main() -> io::Result<()> {
     write_to_file()?;
     read_from_file()?;
-    remove_file(FILE_PATH)
+    remove_file(REQUEST_FILE_PATH)?;
+    remove_file(RESPONSE_FILE_PATH)
 }

examples/rust/types.t

@@ -3,3 +3,8 @@ struct SendEmailRequest {
     subject: String = 1
     body: String = 2
 }
+
+choice SendEmailResponse {
+    success = 0
+    error: String = 1
+}

examples/typescript/src/main.ts

@@ -1,43 +1,78 @@
 import { readFileSync, writeFileSync, unlinkSync } from 'fs';
-import { Types } from '../generated/types';
+import { Types, unreachable } from '../generated/types';
 
-const filePath = '/tmp/message';
-const { SendEmailRequest } = Types;
+const requestFilePath = '/tmp/request';
+const responseFilePath = '/tmp/response';
+const { SendEmailRequest, SendEmailResponse } = Types;
 
 function writeToFile(): void {
-  const message = {
+  const requestMessage = {
     to: '[email protected]',
     subject: 'I love Typical!',
     body: 'It makes serialization easy and safe.',
   };
 
-  const arrayBuffer = SendEmailRequest.serialize(message);
-  writeFileSync(filePath, Buffer.from(arrayBuffer));
+  const responseMessage = {
+    error: 'Example error',
+  };
+
+  const requestArrayBuffer = SendEmailRequest.serialize(requestMessage);
+  writeFileSync(requestFilePath, Buffer.from(requestArrayBuffer));
+
+  const responseArrayBuffer = SendEmailResponse.serialize(responseMessage);
+  writeFileSync(responseFilePath, Buffer.from(responseArrayBuffer));
 }
 
 function readFromFile(): void {
-  const fileContents = readFileSync(filePath);
-  const message = SendEmailRequest.deserialize(
+  const requestFileContents = readFileSync(requestFilePath);
+  const requestMessage = SendEmailRequest.deserialize(
+    new DataView(
+      requestFileContents.buffer,
+      requestFileContents.byteOffset,
+      requestFileContents.byteLength,
+    ),
+  );
+
+  if (requestMessage instanceof Error) {
+    throw requestMessage;
+  }
+
+  const responseFileContents = readFileSync(responseFilePath);
+  const responseMessage = SendEmailResponse.deserialize(
     new DataView(
-      fileContents.buffer,
-      fileContents.byteOffset,
-      fileContents.byteLength,
+      responseFileContents.buffer,
+      responseFileContents.byteOffset,
+      responseFileContents.byteLength,
     ),
   );
 
-  if (message instanceof Error) {
-    throw message;
+  if (responseMessage instanceof Error) {
+    throw responseMessage;
   }
 
   /* eslint-disable no-console -- Allow logging for this example. */
 
-  console.log('to:', message.to);
-  console.log('subject:', message.subject);
-  console.log('body:', message.body);
+  console.log('to:', requestMessage.to);
+  console.log('subject:', requestMessage.subject);
+  console.log('body:', requestMessage.body);
+
+  switch (responseMessage.$field) {
+    case 'success':
+      console.log('The email was sent!');
+      break;
+    case 'error':
+      console.log('An error occurred:', responseMessage.error);
+      break;
+    default:
+      return unreachable(responseMessage);
+  }
 
   /* eslint-enable no-console -- Re-enable this rule. */
+
+  return undefined; // To satisfy ESLint's `consistent-return` rule
 }
 
 writeToFile();
 readFromFile();
-unlinkSync(filePath);
+unlinkSync(requestFilePath);
+unlinkSync(responseFilePath);

examples/typescript/types.t

@@ -3,3 +3,8 @@ struct SendEmailRequest {
     subject: String = 1
     body: String = 2
 }
+
+choice SendEmailResponse {
+    success = 0
+    error: String = 1
+}