Expand recipes algorithm through development tools

src/compression/tar/tar-strip-prefix.md

@@ -7,8 +7,8 @@ the specified path prefix (`bundle/logs`).  Finally, extract the [`tar::Entry`]
 via [`Entry::unpack`].
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
+#[macro_use]
+extern crate error_chain;
 extern crate flate2;
 extern crate tar;
 
@@ -16,13 +16,13 @@ use std::fs::File;
 use std::path::PathBuf;
 use flate2::read::GzDecoder;
 use tar::Archive;
-# 
-# error_chain! {
-#   foreign_links {
-#     Io(std::io::Error);
-#     StripPrefixError(::std::path::StripPrefixError);
-#   }
-# }
+
+error_chain! {
+  foreign_links {
+    Io(std::io::Error);
+    StripPrefixError(::std::path::StripPrefixError);
+  }
+}
 
 fn main() -> Result<()> {
     let file = File::open("archive.tar.gz")?;

src/concurrency/parallel/rayon-thumbnails.md

@@ -9,8 +9,8 @@ then saves them in a new folder called `thumbnails`.
 images in parallel using [`par_iter`] calling  [`DynamicImage::resize`].
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
+#[macro_use]
+extern crate error_chain;
 extern crate glob;
 extern crate image;
 extern crate rayon;
@@ -18,18 +18,18 @@ extern crate rayon;
 use std::path::Path;
 use std::fs::create_dir_all;
 
-# use error_chain::ChainedError;
+use error_chain::ChainedError;
 use glob::{glob_with, MatchOptions};
 use image::{FilterType, ImageError};
 use rayon::prelude::*;
 
-# error_chain! {
-#     foreign_links {
-#         Image(ImageError);
-#         Io(std::io::Error);
-#         Glob(glob::PatternError);
-#     }
-# }
+error_chain! {
+    foreign_links {
+        Image(ImageError);
+        Io(std::io::Error);
+        Glob(glob::PatternError);
+    }
+}
 
 fn main() -> Result<()> {
     let options: MatchOptions = Default::default();

src/cryptography/encryption.md

@@ -1,5 +1,4 @@
 # Encryption
 
-{{#include encryption/pbkdf2.md}}
 
 {{#include ../links.md}}

src/cryptography/hashing.md

@@ -4,4 +4,6 @@
 
 {{#include hashing/hmac.md}}
 
+{{#include encryption/pbkdf2.md}}
+
 {{#include ../links.md}}

src/database/postgres/aggregate_data.md

@@ -2,7 +2,11 @@
 
 [![postgres-badge]][postgres] [![cat-database-badge]][cat-database]
 
-This recipe lists the nationalities of the first 7999 artists in the database of the [`Museum of Modern Art`] in descending order.
+This recipe lists the nationalities of the first 7999 artists in the database of the [`Museum of Modern Art`] in
+descending order.
+
+In this example, a local postgres instance rows in a Nation struct.  A GROUP BY clause collects the artists into their
+nationality.
 
 ```rust,no_run
 extern crate postgres;

src/database/postgres/create_tables.md

@@ -4,7 +4,8 @@
 
 Use the [`postgres`] crate to create tables in a Postgres database.
 
-[`Connection::connect`] helps in connecting to an existing database. The recipe uses a URL string format with `Connection::connect`. It assumes an existing database named `library`, the username is `postgres` and the password is `postgres`.
+[`Connection::connect`] connects to an existing database. The recipe uses a URL string format with `Connection::connect`.
+The recipe requires an existing database named `library`, with a `postgres` user with `postgres` password.
 
 ```rust,no_run
 extern crate postgres;

src/database/postgres/insert_query_data.md

@@ -2,7 +2,8 @@
 
 [![postgres-badge]][postgres] [![cat-database-badge]][cat-database]
 
-The recipe inserts data into the `author` table using [`execute`] method of `Connection`. Then, displays the data from the `author` table  using [`query`] method of `Connection`.
+The recipe inserts data into the `author` table using [`execute`] method of `Connection`.
+Then, displays the data from the `author` table  using [`query`] method of `Connection`.
 
 ```rust,no_run
 extern crate postgres;

src/database/sqlite/initialization.md

@@ -3,7 +3,8 @@
 [![rusqlite-badge]][rusqlite] [![cat-database-badge]][cat-database]
 
 Use the `rusqlite` crate to open SQLite databases. See
-[crate][documentation] for compiling on Windows.
+[crate][documentation] for compiling on Windows.  SQLite databases are single-file and do not require a database
+management service to run.
 
 [`Connection::open`] will create the database if it doesn't already exist.
 

src/datetime/duration/profile.md

@@ -9,11 +9,11 @@ This method will not mutate or reset the [`time::Instant`] object.
 
 ```rust
 use std::time::{Duration, Instant};
-# use std::thread;
-#
-# fn expensive_function() {
-#     thread::sleep(Duration::from_secs(1));
-# }
+use std::thread;
+
+fn expensive_function() {
+    thread::sleep(Duration::from_secs(1));
+}
 
 fn main() {
     let start = Instant::now();

src/development_tools/build_tools/cc-bundled-static.md

@@ -58,25 +58,25 @@ void greet(const char* name) {
 ### `src/main.rs`
 
 ```rust,ignore
-# #[macro_use] extern crate error_chain;
+#[macro_use] extern crate error_chain;
 use std::ffi::CString;
 use std::os::raw::c_char;
-#
-# error_chain! {
-#     foreign_links {
-#         NulError(::std::ffi::NulError);
-#         Io(::std::io::Error);
-#     }
-# }
-#
-# fn prompt(s: &str) -> Result<String> {
-#     use std::io::Write;
-#     print!("{}", s);
-#     std::io::stdout().flush()?;
-#     let mut input = String::new();
-#     std::io::stdin().read_line(&mut input)?;
-#     Ok(input.trim().to_string())
-# }
+
+error_chain! {
+    foreign_links {
+        NulError(::std::ffi::NulError);
+        Io(::std::io::Error);
+    }
+}
+
+fn prompt(s: &str) -> Result<String> {
+    use std::io::Write;
+    print!("{}", s);
+    std::io::stdout().flush()?;
+    let mut input = String::new();
+    std::io::stdin().read_line(&mut input)?;
+    Ok(input.trim().to_string())
+}
 
 extern {
     fn hello();

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

@@ -12,8 +12,8 @@ Assigns the configuration to [`log4rs::config::Config`] and sets the default
 [`log::LevelFilter`].
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
+#[macro_use]
+extern crate error_chain;
 #[macro_use]
 extern crate log;
 extern crate log4rs;
@@ -22,14 +22,14 @@ use log::LevelFilter;
 use log4rs::append::file::FileAppender;
 use log4rs::encode::pattern::PatternEncoder;
 use log4rs::config::{Appender, Config, Root};
-#
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#         LogConfig(log4rs::config::Errors);
-#         SetLogger(log::SetLoggerError);
-#     }
-# }
+
+error_chain! {
+    foreign_links {
+        Io(std::io::Error);
+        LogConfig(log4rs::config::Errors);
+        SetLogger(log::SetLoggerError);
+    }
+}
 
 fn main() -> Result<()> {
     let logfile = FileAppender::builder()

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

@@ -7,16 +7,18 @@ with [`syslog::init`]. [`syslog::Facility`] records the program submitting
 the log entry's classification, [`log::LevelFilter`] denotes allowed log verbosity
 and `Option<&str>` holds optional application name.
 
+This recipe demonstrates filtering crates, functions, and use statements by the operating system with `#[cfg(target_os)]`
+
 ```rust
 #[macro_use]
 extern crate log;
-# #[cfg(target_os = "linux")]
+#[cfg(target_os = "linux")]
 extern crate syslog;
 
-# #[cfg(target_os = "linux")]
+#[cfg(target_os = "linux")]
 use syslog::{Facility, Error};
 
-# #[cfg(target_os = "linux")]
+#[cfg(target_os = "linux")]
 fn main() -> Result<(), Error> {
     syslog::init(Facility::LOG_USER,
                  log::LevelFilter::Debug,
@@ -26,10 +28,10 @@ fn main() -> Result<(), Error> {
     Ok(())
 }
 
-# #[cfg(not(target_os = "linux"))]
-# fn main() {
-#     println!("So far, only Linux systems are supported.");
-# }
+#[cfg(not(target_os = "linux"))]
+fn main() {
+    println!("So far, only Linux systems are supported.");
+}
 ```
 
 [`log::LevelFilter`]: https://docs.rs/log/*/log/enum.LevelFilter.html

src/development_tools/versioning/semver-command.md

@@ -8,21 +8,21 @@ Runs `git --version` using [`Command`], then parses the version number into a
 "git version x.y.z".
 
 ```rust,no_run
-# #[macro_use]
-# extern crate error_chain;
+#[macro_use]
+extern crate error_chain;
 extern crate semver;
 
 use std::process::Command;
 use semver::{Version, VersionReq};
-#
-# error_chain! {
-#     foreign_links {
-#         Io(std::io::Error);
-#         Utf8(std::string::FromUtf8Error);
-#         SemVer(semver::SemVerError);
-#         SemVerReq(semver::ReqParseError);
-#     }
-# }
+
+error_chain! {
+    foreign_links {
+        Io(std::io::Error);
+        Utf8(std::string::FromUtf8Error);
+        SemVer(semver::SemVerError);
+        SemVerReq(semver::ReqParseError);
+    }
+}
 
 fn main() -> Result<()> {
     let version_constraint = "> 1.12.0";

src/development_tools/versioning/semver-latest.md

@@ -7,18 +7,18 @@ Given a list of version &strs, finds the latest [`semver::Version`].
 Also demonstrates `semver` pre-release preferences.
 
 ```rust
-# #[macro_use]
-# extern crate error_chain;
+#[macro_use]
+extern crate error_chain;
 extern crate semver;
 
 use semver::{Version, VersionReq};
-#
-# error_chain! {
-#     foreign_links {
-#         SemVer(semver::SemVerError);
-#         SemVerReq(semver::ReqParseError);
-#     }
-# }
+
+error_chain! {
+    foreign_links {
+        SemVer(semver::SemVerError);
+        SemVerReq(semver::ReqParseError);
+    }
+}
 
 fn find_max_matching_version<'a, I>(version_req_str: &str, iterable: I) -> Result<Option<Version>>
 where