removed error-chain from examples having only one error variant (#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

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

@@ -10,22 +10,15 @@ 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<()> {
+fn main() -> Result<(), Unspecified> {
     const CREDENTIAL_LEN: usize = digest::SHA512_OUTPUT_LEN;
     const N_ITER: u32 = 100_000;
     let rng = rand::SystemRandom::new();
@@ -66,8 +59,6 @@ fn run() -> Result<()> {
 
     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

@@ -8,26 +8,16 @@ 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"))?;
@@ -35,15 +25,11 @@ fn run() -> Result<()> {
     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

src/encoding/complex/endian-byte.md

@@ -7,25 +7,18 @@ be necessary when receiving information over the network, such that bytes
 received are from another system.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate byteorder;
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use std::io::Error;
 
 #[derive(Default, PartialEq, Debug)]
 struct Payload {
     kind: u8,
     value: u16,
 }
-#
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let original_payload = Payload::default();
     let encoded_bytes = encode(&original_payload)?;
     let decoded_payload = decode(&encoded_bytes)?;
@@ -33,20 +26,18 @@ fn run() -> Result<()> {
     Ok(())
 }
 
-fn encode(payload: &Payload) -> Result<Vec<u8>> {
+fn encode(payload: &Payload) -> Result<Vec<u8>, Error> {
     let mut bytes = vec![];
     bytes.write_u8(payload.kind)?;
     bytes.write_u16::<LittleEndian>(payload.value)?;
     Ok(bytes)
 }
 
-fn decode(mut bytes: &[u8]) -> Result<Payload> {
+fn decode(mut bytes: &[u8]) -> Result<Payload, Error> {
     let payload = Payload {
         kind: bytes.read_u8()?,
         value: bytes.read_u16::<LittleEndian>()?,
     };
     Ok(payload)
 }
-#
-# quick_main!(run);
 ```

src/encoding/complex/json.md

@@ -11,20 +11,12 @@ is able to represent any valid JSON data.
 The example below shows a `&str` of JSON being parsed.  The expected value is declared using the [`json!`] macro.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 #[macro_use]
 extern crate serde_json;
 
-use serde_json::Value;
-#
-# error_chain! {
-#     foreign_links {
-#         Json(serde_json::Error);
-#     }
-# }
+use serde_json::{Value, Error};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let j = r#"{
                  "userid": 103609,
                  "verified": true,
@@ -49,8 +41,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`from_str`]: https://docs.serde.rs/serde_json/fn.from_str.html

src/encoding/complex/toml.md

@@ -6,19 +6,11 @@ Parse some TOML into a universal `toml::Value` that is able to represent any
 valid TOML data.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate toml;
 
-use toml::Value;
-#
-# error_chain! {
-#     foreign_links {
-#         Toml(toml::de::Error);
-#     }
-# }
+use toml::{Value, de::Error};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let toml_content = r#"
           [package]
           name = "your_package"
@@ -37,8 +29,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 Parse TOML into your own structs using [Serde].

src/encoding/csv/delimiter.md

@@ -5,9 +5,8 @@
 Reads CSV records with a tab [`delimiter`].
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate csv;
+use csv::Error;
 #[macro_use]
 extern crate serde_derive;
 
@@ -20,14 +19,8 @@ struct Record {
 }
 
 use csv::ReaderBuilder;
-#
-# error_chain! {
-#     foreign_links {
-#         CsvError(csv::Error);
-#     }
-# }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let data = "name\tplace\tid
 		Mark\tMelbourne\t46
 		Ashley\tZurich\t92";
@@ -39,8 +32,6 @@ Ashley\tZurich\t92";
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`delimiter`]: https://docs.rs/csv/1.0.0-beta.3/csv/struct.ReaderBuilder.html#method.delimiter

src/encoding/csv/invalid.md

@@ -7,9 +7,8 @@ provides a custom deserializer, [`csv::invalid_option`], which automatically
 converts invalid data to None values.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate csv;
+use csv::Error;
 #[macro_use]
 extern crate serde_derive;
 
@@ -20,14 +19,8 @@ struct Record {
     #[serde(deserialize_with = "csv::invalid_option")]
     id: Option<u64>,
 }
-#
-# error_chain! {
-#     foreign_links {
-#         CsvError(csv::Error);
-#     }
-# }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let data = "name,place,id
 mark,sydney,46.5
 ashley,zurich,92
@@ -42,8 +35,6 @@ alisha,colombo,xyz";
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`csv::invalid_option`]: https://docs.rs/csv/*/csv/fn.invalid_option.html

src/encoding/csv/read.md

@@ -8,16 +8,9 @@ data representation which expects valid UTF-8 rows. Alternatively,
 
 ```rust
 extern crate csv;
-# #[macro_use]
-# extern crate error_chain;
-#
-# error_chain! {
-#     foreign_links {
-#         Reader(csv::Error);
-#     }
-# }
+use csv::Error;
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let csv = "year,make,model,description
 		1948,Porsche,356,Luxury sports car
 		1967,Ford,Mustang fastback 1967,American car";
@@ -36,8 +29,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 Serde deserializes data into strongly type structures. See the

src/encoding/string/hex.md

@@ -13,19 +13,11 @@ The example below coverts `&[u8]` data to hexadecimal equivalent.  Compares this
 value to the expected value.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate data_encoding;
 
 use data_encoding::{HEXUPPER, DecodeError};
-#
-# error_chain! {
-#     foreign_links {
-#         Decode(DecodeError);
-#     }
-# }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), DecodeError> {
     let original = b"The quick brown fox jumps over the lazy dog.";
     let expected = "54686520717569636B2062726F776E20666F78206A756D7073206F76\
         657220746865206C617A7920646F672E";
@@ -38,8 +30,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`data_encoding`]: https://docs.rs/data-encoding/*/data_encoding/

src/encoding/string/percent-encode.md

@@ -7,19 +7,12 @@ function from the `url` crate. Then decode using the [`percent_decode`]
 function.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate url;
 
 use url::percent_encoding::{utf8_percent_encode, percent_decode, DEFAULT_ENCODE_SET};
-#
-# error_chain! {
-#     foreign_links {
-#         Utf8(std::str::Utf8Error);
-#     }
-# }
+use std::str::Utf8Error;
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Utf8Error> {
     let input = "confident, productive systems programming";
 
     let iter = utf8_percent_encode(input, DEFAULT_ENCODE_SET);
@@ -32,8 +25,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 The encode set defines which bytes (in addition to non-ASCII and controls) need

src/file/read-write/memmap.md

@@ -11,21 +11,13 @@ behind the memory map is not being modified at the same time by another process
 or else a [race condition] occurs.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate memmap;
 
 use memmap::Mmap;
-# use std::fs::File;
-# use std::io::Write;
-#
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
+use std::fs::File;
+use std::io::{Write, Error};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
 #     write!(File::create("content.txt")?, "My hovercraft is full of eels!")?;
 #
     let file = File::open("content.txt")?;
@@ -39,8 +31,6 @@ fn run() -> Result<()> {
     assert_eq!(&random_bytes[..], b"My loaf!");
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`Mmap::map`]: https://docs.rs/memmap/*/memmap/struct.Mmap.html#method.map

src/file/read-write/read-file.md

@@ -9,19 +9,10 @@ trait.  [`File::create`] opens a [`File`] for writing, [`File::open`] for
 reading.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
-#
 use std::fs::File;
-use std::io::{Write, BufReader, BufRead};
-#
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
+use std::io::{Write, BufReader, BufRead, Error};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let path = "lines.txt";
 
     let mut output = File::create(path)?;
@@ -36,8 +27,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`BufRead::lines`]: https://doc.rust-lang.org/std/io/trait.BufRead.html#method.lines

src/file/read-write/same-file.md

@@ -7,29 +7,24 @@ other handles. In this example, the handles of file to be read from and
 to be written to are tested for equality.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
 extern crate same_file;
 
 use same_file::Handle;
-use std::path::Path;
 use std::fs::File;
-use std::io::{BufRead, BufReader};
-#
-# error_chain! {
-#     foreign_links {
-#          IOError(::std::io::Error);
-#     }
-# }
+use std::io::{BufRead, BufReader, Error, ErrorKind};
+use std::path::Path;
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let path_to_read = Path::new("new.txt");
 
     let stdout_handle = Handle::stdout()?;
     let handle = Handle::from_path(path_to_read)?;
 
     if stdout_handle == handle {
-        bail!("You are reading and writing to the same file");
+        return Err(Error::new(
+            ErrorKind::Other,
+            "You are reading and writing to the same file",
+        ));
     } else {
         let file = File::open(&path_to_read)?;
         let file = BufReader::new(file);
@@ -40,8 +35,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 ```bash

src/net/server/listen-unused.md

@@ -7,19 +7,10 @@ listen until a request is made.  `SocketAddrV4` assigns a random port when
 setting port to 0.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
-#
 use std::net::{SocketAddrV4, Ipv4Addr, TcpListener};
-use std::io::Read;
-#
-# error_chain! {
-#     foreign_links {
-#         Io(::std::io::Error);
-#     }
-# }
+use std::io::{Read, Error};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let loopback = Ipv4Addr::new(127, 0, 0, 1);
     let socket = SocketAddrV4::new(loopback, 0);
     let listener = TcpListener::bind(socket)?;
@@ -32,6 +23,4 @@ fn run() -> Result<()> {
     println!("{:?} says {}", addr, input);
     Ok(())
 }
-#
-# quick_main!(run);
 ```

src/os/external/continuous.md

@@ -11,24 +11,15 @@ The below recipe is equivalent to the Unix shell command
 `journalctl | grep usb`.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
-#
 use std::process::{Command, Stdio};
-use std::io::{BufRead, BufReader};
+use std::io::{BufRead, BufReader, Error, ErrorKind};
 
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
-#
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let stdout = Command::new("journalctl")
         .stdout(Stdio::piped())
         .spawn()?
         .stdout
-        .ok_or_else(|| "Could not capture standard output.")?;
+        .ok_or_else(|| Error::new(ErrorKind::Other,"Could not capture standard output."))?;
 
     let reader = BufReader::new(stdout);
 
@@ -40,8 +31,6 @@ fn run() -> Result<()> {
 
      Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`BufReader`]: https://doc.rust-lang.org/std/io/struct.BufReader.html

src/os/external/error-file.md

@@ -13,19 +13,11 @@ The below recipe is equivalent to run the Unix shell command `ls
 . oops >out.txt 2>&1`.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
-#
 use std::fs::File;
+use std::io::Error;
 use std::process::{Command, Stdio};
 
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#     }
-# }
-#
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let outputs = File::create("out.txt")?;
     let errors = outputs.try_clone()?;
 
@@ -38,8 +30,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`File::try_clone`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.try_clone

src/web/clients/api/paginated.md

@@ -7,17 +7,10 @@ fetches the next page of results from the remote server as it arrives at the end
 of each page.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
 #[macro_use]
 extern crate serde_derive;
 extern crate reqwest;
-#
-# error_chain! {
-#     foreign_links {
-#         Reqwest(reqwest::Error);
-#     }
-# }
+use reqwest::Error;
 
 #[derive(Deserialize)]
 struct ApiResponse {
@@ -45,7 +38,7 @@ struct ReverseDependencies {
 }
 
 impl ReverseDependencies {
-    fn of(crate_id: &str) -> Result<Self> {
+    fn of(crate_id: &str) -> Result<Self, Error> {
         Ok(ReverseDependencies {
                crate_id: crate_id.to_owned(),
                dependencies: vec![].into_iter(),
@@ -56,7 +49,7 @@ impl ReverseDependencies {
            })
     }
 
-    fn try_next(&mut self) -> Result<Option<Dependency>> {
+    fn try_next(&mut self) -> Result<Option<Dependency>, Error> {
         if let Some(dep) = self.dependencies.next() {
             return Ok(Some(dep));
         }
@@ -79,7 +72,7 @@ impl ReverseDependencies {
 }
 
 impl Iterator for ReverseDependencies {
-    type Item = Result<Dependency>;
+    type Item = Result<Dependency, Error>;
 
     fn next(&mut self) -> Option<Self::Item> {
         match self.try_next() {
@@ -90,12 +83,10 @@ impl Iterator for ReverseDependencies {
     }
 }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     for dep in ReverseDependencies::of("serde")? {
         println!("reverse dependency: {}", dep?.crate_id);
     }
     Ok(())
 }
-#
-# quick_main!(run);
 ```

src/web/clients/api/rest-get.md

@@ -6,25 +6,18 @@ Queries GitHub [stargazers API v3](https://developer.github.com/v3/activity/star
 with [`reqwest::get`] to get list of all users who have marked a GitHub project with a star. [`reqwest::Response`] is deserialized with [`Response::json`] into `User` objects implementing [`serde::Deserialize`].
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
 #[macro_use]
 extern crate serde_derive;
 extern crate reqwest;
+use reqwest::Error;
 
 #[derive(Deserialize, Debug)]
 struct User {
     login: String,
     id: u32,
 }
-#
-# error_chain! {
-#     foreign_links {
-#         Reqwest(reqwest::Error);
-#     }
-# }
 
-fn run() -> Result<()> {
+fn main() -> Result<(), Error> {
     let request_url = format!("https://api.github.com/repos/{owner}/{repo}/stargazers",
                               owner = "rust-lang-nursery",
                               repo = "rust-cookbook");
@@ -35,8 +28,6 @@ fn run() -> Result<()> {
     println!("{:?}", users);
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`reqwest::get`]: https://docs.rs/reqwest/*/reqwest/fn.get.html

src/web/clients/api/rest-head.md

@@ -9,20 +9,14 @@ a body. [`reqwest::Client`] cofigured with [`ClientBuilder::timeout`] ensures
 a request will not last longer than a timeout.
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
 extern crate reqwest;
 
+use reqwest::Error;
 use std::time::Duration;
 use reqwest::ClientBuilder;
-#
-# error_chain! {
-#     foreign_links {
-#         Reqwest(reqwest::Error);
-#     }
-# }
 
-fn run() -> Result<()> {
+
+fn main() -> Result<(), Error> {
     let user = "ferris-the-crab";
     let request_url = format!("https://api.github.com/users/{}", user);
     println!("{}", request_url);
@@ -39,8 +33,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`Client::head`]: https://docs.rs/reqwest/*/reqwest/struct.Client.html#method.head

src/web/url/fragment.md

@@ -5,26 +5,17 @@
 Parses [`Url`] and slices it with [`url::Position`] to strip unneeded URL parts.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
+
 extern crate url;
 
-use url::{Url, Position};
-#
-# error_chain! {
-#     foreign_links {
-#         UrlParse(url::ParseError);
-#     }
-# }
+use url::{Url, Position, ParseError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), ParseError> {
     let parsed = Url::parse("https://github.com/rust-lang/rust/issues?labels=E-easy&state=open")?;
     let cleaned: &str = &parsed[..Position::AfterPath];
     println!("cleaned: {}", cleaned);
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`url::Position`]: https://docs.rs/url/*/url/enum.Position.html

src/web/url/new.md

@@ -5,19 +5,11 @@
 The [`join`] method creates a new URL from a base and relative path.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate url;
 
-use url::Url;
-#
-# error_chain! {
-#     foreign_links {
-#         UrlParse(url::ParseError);
-#     }
-# }
+use url::{Url, ParseError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), ParseError> {
     let path = "/rust-lang/cargo";
 
     let gh = build_github_url(path)?;
@@ -28,7 +20,7 @@ fn run() -> Result<()> {
     Ok(())
 }
 
-fn build_github_url(path: &str) -> Result<Url> {
+fn build_github_url(path: &str) -> Result<Url, ParseError> {
     const GITHUB: &'static str = "https://github.com";
 
     let base = Url::parse(GITHUB).expect("hardcoded URL is known to be valid");
@@ -36,8 +28,6 @@ fn build_github_url(path: &str) -> Result<Url> {
 
     Ok(joined)
 }
-#
-# quick_main!(run);
 ```
 
 [`join`]: https://docs.rs/url/*/url/struct.Url.html#method.join

src/web/url/origin.md

@@ -6,19 +6,11 @@ The [`Url`] struct exposes various methods to extract information about the URL
 it represents.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate url;
 
-use url::{Url, Host};
+use url::{Url, Host, ParseError};
 
-# error_chain! {
-#     foreign_links {
-#         UrlParse(url::ParseError);
-#     }
-# }
-#
-fn run() -> Result<()> {
+fn main() -> Result<(), ParseError> {
     let s = "ftp://rust-lang.org/examples";
 
     let url = Url::parse(s)?;
@@ -30,8 +22,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`origin`] produces the same result.

src/web/url/parse.md

@@ -10,19 +10,11 @@ Once the URL has been parsed, it can be used with all of the methods in the
 `Url` type.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
 extern crate url;
 
-use url::Url;
-#
-# error_chain! {
-#     foreign_links {
-#         UrlParse(url::ParseError);
-#     }
-# }
+use url::{Url, ParseError};
 
-fn run() -> Result<()> {
+fn main() -> Result<(), ParseError> {
     let s = "https://github.com/rust-lang/rust/issues?labels=E-easy&state=open";
 
     let parsed = Url::parse(s)?;
@@ -30,8 +22,6 @@ fn run() -> Result<()> {
 
     Ok(())
 }
-#
-# quick_main!(run);
 ```
 
 [`parse`]: https://docs.rs/url/*/url/struct.Url.html#method.parse