removed error-chain from examples having only one error variant (rust-lang-nursery#525)

* removed error-chain from 'Calculate SHA1 sum of iso files concurrently'

* removed error chain from 'Salt and hash a password with PBKDF2'

* removed error-chain from 'Parse string into DateTime struct'

* removed error-chain from 'Log messages with a custom logger'

* fixed compiler errors

* removed unnecessary feature flag

* removed error-chain from 'Log to the Unix syslog'

* removed error-chain from 'Parse and increment a version string.'

* removed error-chain from 'Parse a complex version string.'

* removed error-chain from 'Check if given version is pre-release.'

* removed error-chain from 'Percent-encode a string'

* removed error-chain from 'Encode and decode hex'

* removed error-chain from 'Read CSV records'

* removed error-chain from 'Read CSV records with different delimiter'

* removed error-chain from 'Handle invalid CSV data with Serde'

* removed error-chain from 'Serialize and deserialize unstructured JSON'

* removed error-chain from 'Deserialize a TOML configuration file'

* removed error-chain from 'Read and write integers in little-endian byte order'

* removed error-chain from 'Read lines of strings from a file'

* removed error-chain from 'Avoid writing and reading from a same file'

* removed error-chain from 'Access a file randomly using a memory map'

* removed error-chain from 'Listen on unused port TCP/IP'

* removed error-chain from 'Redirect both stdout and stderr of child process to the same file'

* removed error-chain from 'Continuously process child process' outputs'

* removed error-chain from 'Parse a URL from a string to a `Url` type'

* removed error-chain from 'Create new URLs from a base URL'

* removed error-chain from 'Extract the URL origin (scheme / host / port)'

* removed error-chain from 'Remove fragment identifiers and query pairs from a URL'

* removed error-chain from 'Query the GitHub API'

* removed error-chain from 'Check if an API resource exists'

* removed error-chain from 'Consume a paginated RESTful API'

* addressed Travis CI failure

* addressed Travis CI failure

* addressed Travis CI issue

Author: KappaDistributive

src/concurrency/thread/threadpool-walk.md

@@ -9,22 +9,14 @@ the current directory and calls [`execute`] to perform the operations of reading
 and computing SHA1 hash.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
 extern crate walkdir;
 extern crate ring;
 extern crate num_cpus;
 extern crate threadpool;
 
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
-#
 use walkdir::WalkDir;
 use std::fs::File;
-use std::io::{BufReader, Read};
+use std::io::{BufReader, Read, Error};
 use std::path::Path;
 use threadpool::ThreadPool;
 use std::sync::mpsc::channel;
@@ -37,8 +29,8 @@ use ring::digest::{Context, Digest, SHA1};
 #         _ => false,
 #     }
 # }
-#
-fn compute_digest<P: AsRef<Path>>(filepath: P) -> Result<(Digest, P)> {
+
+fn compute_digest<P: AsRef<Path>>(filepath: P) -> Result<(Digest, P), Error> {
     let mut buf_reader = BufReader::new(File::open(&filepath)?);
     let mut context = Context::new(&SHA1);
     let mut buffer = [0; 1024];
@@ -54,7 +46,7 @@ fn compute_digest<P: AsRef<Path>>(filepath: P) -> Result<(Digest, P)> {
     Ok((context.finish(), filepath))
 }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let pool = ThreadPool::new(num_cpus::get());
 
     let (tx, rx) = channel();
@@ -79,8 +71,6 @@ fn run() -> Result<()> {
     }
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`execute`]: https://docs.rs/threadpool/*/threadpool/struct.ThreadPool.html#method.execute

src/cryptography/encryption/pbkdf2.md

@@ -10,64 +10,55 @@ function [`pbkdf2::derive`].  Verifies the hash is correct with
 securely generated random numbers.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
-extern crate data_encoding;
 extern crate ring;
-#
-# error_chain! {
-#   foreign_links {
-#     Ring(ring::error::Unspecified);
-#   }
-# }
+extern crate data_encoding;
 
 use data_encoding::HEXUPPER;
-use ring::{digest, pbkdf2, rand};
+use ring::error::Unspecified;
 use ring::rand::SecureRandom;
+use ring::{digest, pbkdf2, rand};
 
-fn run() -> Result<()> {
-  const CREDENTIAL_LEN: usize = digest::SHA512_OUTPUT_LEN;
-  const N_ITER: u32 = 100_000;
-  let rng = rand::SystemRandom::new();
+fn main() -> Result<(), Unspecified> {
+    const CREDENTIAL_LEN: usize = digest::SHA512_OUTPUT_LEN;
+    const N_ITER: u32 = 100_000;
+    let rng = rand::SystemRandom::new();
 
-  let mut salt = [0u8; CREDENTIAL_LEN];
-  rng.fill(&mut salt)?;
+    let mut salt = [0u8; CREDENTIAL_LEN];
+    rng.fill(&mut salt)?;
 
-  let password = "Guess Me If You Can!";
-  let mut pbkdf2_hash = [0u8; CREDENTIAL_LEN];
-  pbkdf2::derive(
-      &digest::SHA512,
-      N_ITER,
-      &salt,
-      password.as_bytes(),
-      &mut pbkdf2_hash,
-  );
-  println!("Salt: {}", HEXUPPER.encode(&salt));
-  println!("PBKDF2 hash: {}", HEXUPPER.encode(&pbkdf2_hash));
+    let password = "Guess Me If You Can!";
+    let mut pbkdf2_hash = [0u8; CREDENTIAL_LEN];
+    pbkdf2::derive(
+        &digest::SHA512,
+        N_ITER,
+        &salt,
+        password.as_bytes(),
+        &mut pbkdf2_hash,
+    );
+    println!("Salt: {}", HEXUPPER.encode(&salt));
+    println!("PBKDF2 hash: {}", HEXUPPER.encode(&pbkdf2_hash));
 
-  let should_succeed = pbkdf2::verify(
-      &digest::SHA512,
-      N_ITER,
-      &salt,
-      password.as_bytes(),
-      &pbkdf2_hash,
-  );
-  let wrong_password = "Definitely not the correct password";
-  let should_fail = pbkdf2::verify(
-      &digest::SHA512,
-      N_ITER,
-      &salt,
-      wrong_password.as_bytes(),
-      &pbkdf2_hash,
-  );
+    let should_succeed = pbkdf2::verify(
+        &digest::SHA512,
+		N_ITER,
+        &salt,
+        password.as_bytes(),
+        &pbkdf2_hash,
+    );
+    let wrong_password = "Definitely not the correct password";
+    let should_fail = pbkdf2::verify(
+        &digest::SHA512,
+        N_ITER,
+        &salt,
+        wrong_password.as_bytes(),
+        &pbkdf2_hash,
+    );
 
-  assert!(should_succeed.is_ok());
-  assert!(!should_fail.is_ok());
+    assert!(should_succeed.is_ok());
+    assert!(!should_fail.is_ok());
 
-  Ok(())
+    Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`pbkdf2::derive`]: https://briansmith.org/rustdoc/ring/pbkdf2/fn.derive.html

src/cryptography/hashing/hmac.md

@@ -5,20 +5,13 @@
 Uses [`ring::hmac`] to creates a [`hmac::Signature`] of a string then verifies the signature is correct.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate ring;
-#
-# error_chain! {
-#     foreign_links {
-#         Ring(ring::error::Unspecified);
-#     }
-# }
 
 use ring::{digest, hmac, rand};
 use ring::rand::SecureRandom;
+use ring::error::Unspecified;
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Unspecified> {
     let mut key_value = [0u8; 48];
     let rng = rand::SystemRandom::new();
     rng.fill(&mut key_value)?;
@@ -30,8 +23,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`hmac::Signature`]: https://briansmith.org/rustdoc/ring/hmac/struct.Signature.html

src/datetime/parse/string.md

@@ -15,18 +15,11 @@ identifies a date and a time. For parsing dates and times without timezones use
 
 ```rust
 extern crate chrono;
-# #[macro_use]
-# extern crate error_chain;
-#
 use chrono::{DateTime, NaiveDate, NaiveDateTime, NaiveTime};
-#
-# error_chain! {
-#     foreign_links {
-#         DateParse(chrono::format::ParseError);
-#     }
-# }
+use chrono::format::ParseError;
 
-fn run() -> Result<()> {
+
+fn main() -> Result<(), ParseError> {
     let rfc2822 = DateTime::parse_from_rfc2822("Tue, 1 Jul 2003 10:52:37 +0200")?;
     println!("{}", rfc2822);
 
@@ -47,8 +40,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`chrono::format::strftime`]: https://docs.rs/chrono/*/chrono/format/strftime/index.html

src/development_tools/debugging/log/log-custom-logger.md

@@ -7,12 +7,10 @@ In order to use the logging macros, `ConsoleLogger` implements
 the [`log::Log`] trait and [`log::set_logger`] installs it.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 #[macro_use]
 extern crate log;
 
-use log::{Record, Level, Metadata, LevelFilter};
+use log::{Record, Level, Metadata, LevelFilter, SetLoggerError};
 
 static CONSOLE_LOGGER: ConsoleLogger = ConsoleLogger;
 
@@ -31,14 +29,8 @@ impl log::Log for ConsoleLogger {
 
     fn flush(&self) {}
 }
-#
-# error_chain! {
-#     foreign_links {
-#         SetLogger(log::SetLoggerError);
-#     }
-# }
-
-fn run() -> Result<()> {
+
+fn main() -> Result<(), SetLoggerError> {
     log::set_logger(&CONSOLE_LOGGER)?;
     log::set_max_level(LevelFilter::Info);
 
@@ -47,8 +39,6 @@ fn run() -> Result<()> {
     error!("oops");
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`log::Log`]: https://docs.rs/log/*/log/trait.Log.html

src/development_tools/debugging/log/log-syslog.md

@@ -8,42 +8,28 @@ the log entry's classification, [`log::LevelFilter`] denotes allowed log verbosi
 and `Option<&str>` holds optional application name.
 
 ```rust
-# #![allow(unused_imports)]
-# #[macro_use]
-# extern crate error_chain;
 #[macro_use]
 extern crate log;
 # #[cfg(target_os = "linux")]
 extern crate syslog;
 
 # #[cfg(target_os = "linux")]
-use syslog::Facility;
-#
-# #[cfg(target_os = "linux")]
-# error_chain! {
-#     foreign_links {
-#         SetLogger(syslog::Error);
-#     }
-# }
+use syslog::{Facility, Error};
 
 # #[cfg(target_os = "linux")]
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     syslog::init(Facility::LOG_USER,
                  log::LevelFilter::Debug,
                  Some("My app name"))?;
     debug!("this is a debug {}", "message");
     error!("this is an error!");
     Ok(())
 }
-#
-# #[cfg(not(target_os = "linux"))]
-# error_chain! {}
+
 # #[cfg(not(target_os = "linux"))]
-# fn run() -> Result<()> {
-#     Ok(())
+# fn main() {
+#     println!("So far, only Linux systems are supported.");
 # }
-#
-# quick_main!(run);
 ```
 
 [`log::LevelFilter`]: https://docs.rs/log/*/log/enum.LevelFilter.html

src/development_tools/versioning/semver-complex.md

@@ -9,19 +9,11 @@ Note that, in accordance with the Specification, build metadata is parsed but no
 comparing versions. In other words, two versions may be equal even if their build strings differ.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate semver;
 
-use semver::{Identifier, Version};
-#
-# error_chain! {
-#     foreign_links {
-#         SemVer(semver::SemVerError);
-#     }
-# }
+use semver::{Identifier, Version, SemVerError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), SemVerError> {
     let version_str = "1.0.49-125+g72ee7853";
     let parsed_version = Version::parse(version_str)?;
 
@@ -45,8 +37,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`semver::Version`]: https://docs.rs/semver/*/semver/struct.Version.html

src/development_tools/versioning/semver-increment.md

@@ -11,19 +11,11 @@ incrementing the major version number resets both the minor and patch version
 numbers to 0.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate semver;
 
-use semver::Version;
-#
-# error_chain! {
-#     foreign_links {
-#         SemVer(semver::SemVerError);
-#     }
-# }
+use semver::{Version, SemVerError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), SemVerError> {
     let mut parsed_version = Version::parse("0.2.6")?;
 
     assert_eq!(
@@ -51,8 +43,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`semver::Version`]: https://docs.rs/semver/*/semver/struct.Version.html

src/development_tools/versioning/semver-prerelease.md

@@ -5,19 +5,11 @@
 Given two versions, [`is_prerelease`] asserts that one is pre-release and the other is not.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate semver;
 
-use semver::Version;
-#
-# error_chain! {
-#     foreign_links {
-#         SemVer(semver::SemVerError);
-#     }
-# }
+use semver::{Version, SemVerError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), SemVerError> {
     let version_1 = Version::parse("1.0.0-alpha")?;
     let version_2 = Version::parse("1.0.0")?;
 
@@ -26,8 +18,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`is_prerelease`]: https://docs.rs/semver/*/semver/struct.Version.html#method.is_prerelease