From 46b1ca7af2dcd1532dfc15ee60e47369f7ca165e Mon Sep 17 00:00:00 2001
From: "Hatter Jiang@Pixelbook" <jht5945@gmail.com>
Date: Mon, 10 Feb 2020 21:08:27 +0800
Subject: [PATCH] add from, into, try_from, try_into

---
 into/Cargo.lock  |  5 +++++
 into/Cargo.toml  |  9 ++++++++
 into/src/main.rs | 53 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)
 create mode 100644 into/Cargo.lock
 create mode 100644 into/Cargo.toml
 create mode 100644 into/src/main.rs

diff --git a/into/Cargo.lock b/into/Cargo.lock
new file mode 100644
index 0000000..c789192
--- /dev/null
+++ b/into/Cargo.lock
@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "into"
+version = "0.1.0"
diff --git a/into/Cargo.toml b/into/Cargo.toml
new file mode 100644
index 0000000..565db95
--- /dev/null
+++ b/into/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "into"
+version = "0.1.0"
+authors = ["Hatter Jiang@Pixelbook <jht5945@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/into/src/main.rs b/into/src/main.rs
new file mode 100644
index 0000000..f9f89ed
--- /dev/null
+++ b/into/src/main.rs
@@ -0,0 +1,53 @@
+
+use std::convert::{
+    TryInto,
+    TryFrom,
+};
+
+type BoxError = Box<dyn std::error::Error>;
+type XResult<T> = Result<T, BoxError>;
+
+fn do_print<T>(t: T) -> XResult<()> where T: TryInto<String>, T::Error: Into<BoxError> {
+    println!("--> {}", t.try_into().map_err(Into::into)?);
+    Ok(())
+}
+
+fn do_print2<T>(t: T) where T: Into<String> {
+    println!("==> {}", t.into())
+}
+
+struct StructX {
+    name: String,
+}
+
+struct StructY {
+    name: String,
+}
+
+// auto have: TryInto<String> for StructX
+impl TryFrom<StructX> for String {
+    type Error = BoxError;
+
+    fn try_from(sx: StructX) -> XResult<Self> {
+        Ok(format!("NAME: {}", sx.name))
+    }
+}
+
+impl From<StructY> for String {
+
+    fn from(sx: StructY) -> Self {
+        format!("NAME:: {}", sx.name)
+    }
+}
+
+fn main() -> XResult<()> {
+    let x = StructX {
+        name: "hater".to_owned(),
+    };
+    do_print(x)?;
+    let y = StructY {
+        name: "hater".to_owned(),
+    };
+    do_print2(y);
+    Ok(())
+}