From c2426e34f75de78d688e5e532faf54008ba4e564 Mon Sep 17 00:00:00 2001
From: Julio Biason <j.biason@engys.com>
Date: Tue, 7 Feb 2023 17:04:03 -0300
Subject: [PATCH] Testing early stop with options

---
 mapoptiontest/Cargo.lock  |  7 +++++++
 mapoptiontest/Cargo.toml  |  8 ++++++++
 mapoptiontest/README.md   |  4 ++++
 mapoptiontest/src/main.rs | 17 +++++++++++++++++
 4 files changed, 36 insertions(+)
 create mode 100644 mapoptiontest/Cargo.lock
 create mode 100644 mapoptiontest/Cargo.toml
 create mode 100644 mapoptiontest/README.md
 create mode 100644 mapoptiontest/src/main.rs

diff --git a/mapoptiontest/Cargo.lock b/mapoptiontest/Cargo.lock
new file mode 100644
index 0000000..03307f9
--- /dev/null
+++ b/mapoptiontest/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "mapoptiontest"
+version = "0.1.0"
diff --git a/mapoptiontest/Cargo.toml b/mapoptiontest/Cargo.toml
new file mode 100644
index 0000000..655885b
--- /dev/null
+++ b/mapoptiontest/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "mapoptiontest"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/mapoptiontest/README.md b/mapoptiontest/README.md
new file mode 100644
index 0000000..e55dfed
--- /dev/null
+++ b/mapoptiontest/README.md
@@ -0,0 +1,4 @@
+# MapOptionTest
+
+Test how one can stop a collect when a map produces an option and the option is
+none.
diff --git a/mapoptiontest/src/main.rs b/mapoptiontest/src/main.rs
new file mode 100644
index 0000000..6d18bd7
--- /dev/null
+++ b/mapoptiontest/src/main.rs
@@ -0,0 +1,17 @@
+fn main() {
+    let all_evens = [2u8, 4, 6, 8];
+    let result: Result<Vec<_>, _> = all_evens
+        .iter()
+        .map(|value| if value % 2 == 0 { Some(value) } else { None })
+        .map(|opt| opt.ok_or(format!("Not good")))
+        .collect();
+    println!("All Evens: {:?}", result);
+
+    let not_evens = [2, 2, 2, 2, 2, 1];
+    let result: Result<Vec<_>, _> = not_evens
+        .iter()
+        .map(|value| if value % 2 == 0 { Some(value) } else { None })
+        .map(|opt| opt.ok_or(format!("Not good")))
+        .collect();
+    println!("Not Evens: {:?}", result);
+}