From 534ede97008a26db7b345d39c79ae1567c95deb8 Mon Sep 17 00:00:00 2001
From: poorna2152 <poorna2152@gmail.com>
Date: Mon, 8 Apr 2024 11:17:09 +0530
Subject: [PATCH] Add alternate receive bbe

---
 .../alternate-receive/alternate_receive.bal   | 47 +++++++++++++++++++
 .../alternate-receive/alternate_receive.md    |  7 +++
 .../alternate_receive.metatags                |  2 +
 .../alternate-receive/alternate_receive.out   |  3 ++
 examples/index.json                           |  7 +++
 5 files changed, 66 insertions(+)
 create mode 100644 examples/alternate-receive/alternate_receive.bal
 create mode 100644 examples/alternate-receive/alternate_receive.md
 create mode 100644 examples/alternate-receive/alternate_receive.metatags
 create mode 100644 examples/alternate-receive/alternate_receive.out

diff --git a/examples/alternate-receive/alternate_receive.bal b/examples/alternate-receive/alternate_receive.bal
new file mode 100644
index 0000000000..b3503d8820
--- /dev/null
+++ b/examples/alternate-receive/alternate_receive.bal
@@ -0,0 +1,47 @@
+import ballerina/io;
+import ballerina/lang.runtime;
+
+public function main() {
+    worker w1 {
+        2 -> w3;
+    }
+
+    worker w2 {
+        runtime:sleep(2);
+        3 -> w3;
+    }
+
+    worker w3 returns int {
+        // The value of the variable `result` is set as soon as the values from either
+        // worker `w1` or `w2` is received.
+        int result = <- w1 | w2;
+        return result;
+    }
+
+    worker w4 returns error? {
+        int value = 10;
+        if value == 10 {
+            return error("Error in worker 1");
+        }
+        value -> w6;
+    }
+
+    worker w5 {
+        runtime:sleep(2);
+        3 -> w6;
+    }
+
+    worker w6 returns int|error? {
+        // Alternate receive action waits until a message that is not an error is received 
+        // when error is not an expected static type. Since `w4` returns an error it 
+        // waits further and sets the value that is received from `w5`.
+        int a = check <- w4 | w5;
+        return a;
+    }
+
+    int valueW3 = wait w3;
+    io:println(valueW3);
+
+    int|error? valueW6 = wait w6;
+    io:println(valueW6);
+}
diff --git a/examples/alternate-receive/alternate_receive.md b/examples/alternate-receive/alternate_receive.md
new file mode 100644
index 0000000000..374b6519d3
--- /dev/null
+++ b/examples/alternate-receive/alternate_receive.md
@@ -0,0 +1,7 @@
+# Alternate receive
+
+The alternate receive action can be used to receive values from several workers.
+
+::: code alternate_receive.bal :::
+
+::: out alternate_receive.out :::
diff --git a/examples/alternate-receive/alternate_receive.metatags b/examples/alternate-receive/alternate_receive.metatags
new file mode 100644
index 0000000000..62f5262e77
--- /dev/null
+++ b/examples/alternate-receive/alternate_receive.metatags
@@ -0,0 +1,2 @@
+description: This BBE demonstrates the alternate receive action
+keywords: ballerina, ballerina by example, bbe, worker, alternate receive
diff --git a/examples/alternate-receive/alternate_receive.out b/examples/alternate-receive/alternate_receive.out
new file mode 100644
index 0000000000..47036fd588
--- /dev/null
+++ b/examples/alternate-receive/alternate_receive.out
@@ -0,0 +1,3 @@
+$ bal run alternate_receive.bal
+2
+3
diff --git a/examples/index.json b/examples/index.json
index 5f3e2d7193..11061f8f68 100644
--- a/examples/index.json
+++ b/examples/index.json
@@ -1419,6 +1419,13 @@
         "disableVerificationReason": "Includes varying output",
         "isLearnByExample": true
       },
+      {
+        "name": "Alternate receive",
+        "url": "alternate-receive",
+        "verifyBuild": true,
+        "verifyOutput": true,
+        "isLearnByExample": true
+      },
       {
         "name": "Multiple wait",
         "url": "multiple-wait",