Split crate into a binary and a library

Split imdl into a binary, `src/main.rs`, and a library, `src/lib.rs`.

This will enable benchmarking, fuzz testing, and anything that requires
making `imdl` functions accessible another crate.

type: reform

src/common.rs

@@ -15,7 +15,7 @@ pub(crate) use std::{
   num::{ParseFloatError, ParseIntError, TryFromIntError},
   ops::{AddAssign, Div, DivAssign, Mul, MulAssign, Sub, SubAssign},
   path::{self, Path, PathBuf},
-  process::{self, ExitStatus},
+  process::ExitStatus,
   str::{self, FromStr},
   string::FromUtf8Error,
   sync::Once,

src/consts.rs

@@ -34,7 +34,7 @@ pub(crate) const PROGRESS_CHARS: &str = "█▉▊▋▌▍▎▏ ";
 /// Digits are ordered from least significant to most significant from
 /// top to bottom, and then left to right, like so:
 ///
-/// ```
+/// ```text
 /// ╔═════╗
 /// ║ 0 4 ║
 /// ║ 1 5 ║

src/env.rs

@@ -77,7 +77,7 @@ impl Env {
   /// To enable logging in those tests, call `Env::initialize_logging()` like
   /// so:
   ///
-  /// ```
+  /// ```no_run
   /// #[test]
   /// fn foo() {
   ///   Env::initialize_logging();

src/infohash.rs

@@ -1,4 +1,4 @@
-use crate::*;
+use crate::common::*;
 
 #[derive(Debug, Eq, PartialEq, Copy, Clone)]
 pub(crate) struct Infohash {

src/lib.rs

@@ -0,0 +1,106 @@
+#![deny(clippy::all, clippy::pedantic, clippy::restriction)]
+#![allow(
+  clippy::else_if_without_else,
+  clippy::enum_glob_use,
+  clippy::float_arithmetic,
+  clippy::float_cmp,
+  clippy::implicit_return,
+  clippy::indexing_slicing,
+  clippy::integer_arithmetic,
+  clippy::integer_division,
+  clippy::large_enum_variant,
+  clippy::missing_docs_in_private_items,
+  clippy::missing_inline_in_public_items,
+  clippy::needless_pass_by_value,
+  clippy::non_ascii_literal,
+  clippy::option_map_unwrap_or_else,
+  clippy::shadow_reuse,
+  clippy::struct_excessive_bools,
+  clippy::too_many_lines,
+  clippy::unseparated_literal_suffix,
+  clippy::wildcard_enum_match_arm,
+  clippy::wildcard_imports
+)]
+
+#[cfg(test)]
+#[macro_use]
+mod assert_matches;
+
+#[macro_use]
+mod errln;
+
+#[macro_use]
+mod err;
+
+#[macro_use]
+mod out;
+
+#[macro_use]
+mod outln;
+
+#[cfg(test)]
+#[macro_use]
+mod test_env;
+
+#[cfg(test)]
+mod test_env_builder;
+
+#[cfg(test)]
+mod capture;
+
+mod arguments;
+mod bytes;
+mod common;
+mod consts;
+mod env;
+mod error;
+mod file_error;
+mod file_info;
+mod file_path;
+mod file_status;
+mod files;
+mod hasher;
+mod host_port;
+mod host_port_parse_error;
+mod info;
+mod infohash;
+mod input;
+mod input_stream;
+mod input_target;
+mod into_u64;
+mod into_usize;
+mod invariant;
+mod lint;
+mod linter;
+mod magnet_link;
+mod md5_digest;
+mod metainfo;
+mod metainfo_error;
+mod mode;
+mod options;
+mod output_stream;
+mod output_target;
+mod piece_length_picker;
+mod piece_list;
+mod platform;
+mod platform_interface;
+mod print;
+mod reckoner;
+mod run;
+mod sha1_digest;
+mod shell;
+mod sort_key;
+mod sort_order;
+mod sort_spec;
+mod status;
+mod step;
+mod style;
+mod subcommand;
+mod table;
+mod torrent_summary;
+mod use_color;
+mod verifier;
+mod walker;
+mod xor_args;
+
+pub use run::run;

src/main.rs

@@ -1,110 +1,5 @@
-#![deny(clippy::all, clippy::pedantic, clippy::restriction)]
-#![allow(
-  clippy::else_if_without_else,
-  clippy::enum_glob_use,
-  clippy::float_arithmetic,
-  clippy::float_cmp,
-  clippy::implicit_return,
-  clippy::indexing_slicing,
-  clippy::integer_arithmetic,
-  clippy::integer_division,
-  clippy::large_enum_variant,
-  clippy::missing_docs_in_private_items,
-  clippy::needless_pass_by_value,
-  clippy::non_ascii_literal,
-  clippy::option_map_unwrap_or_else,
-  clippy::shadow_reuse,
-  clippy::too_many_lines,
-  clippy::unseparated_literal_suffix,
-  clippy::wildcard_enum_match_arm,
-  clippy::wildcard_imports,
-  clippy::struct_excessive_bools
-)]
-
-use crate::common::*;
-
-#[cfg(test)]
-#[macro_use]
-mod assert_matches;
-
-#[macro_use]
-mod errln;
-
-#[macro_use]
-mod err;
-
-#[macro_use]
-mod out;
-
-#[macro_use]
-mod outln;
-
-#[cfg(test)]
-#[macro_use]
-mod test_env;
-
-#[cfg(test)]
-mod test_env_builder;
-
-#[cfg(test)]
-mod capture;
-
-mod arguments;
-mod bytes;
-mod common;
-mod consts;
-mod env;
-mod error;
-mod file_error;
-mod file_info;
-mod file_path;
-mod file_status;
-mod files;
-mod hasher;
-mod host_port;
-mod host_port_parse_error;
-mod info;
-mod infohash;
-mod input;
-mod input_stream;
-mod input_target;
-mod into_u64;
-mod into_usize;
-mod invariant;
-mod lint;
-mod linter;
-mod magnet_link;
-mod md5_digest;
-mod metainfo;
-mod metainfo_error;
-mod mode;
-mod options;
-mod output_stream;
-mod output_target;
-mod piece_length_picker;
-mod piece_list;
-mod platform;
-mod platform_interface;
-mod print;
-mod reckoner;
-mod sha1_digest;
-mod shell;
-mod sort_key;
-mod sort_order;
-mod sort_spec;
-mod status;
-mod step;
-mod style;
-mod subcommand;
-mod table;
-mod torrent_summary;
-mod use_color;
-mod verifier;
-mod walker;
-mod xor_args;
-
 fn main() {
-  if let Err(code) = Env::main().status() {
-    process::exit(code);
+  if let Err(code) = imdl::run() {
+    std::process::exit(code);
   }
 }

src/run.rs

@@ -0,0 +1,22 @@
+use crate::common::*;
+
+/// Entry point into the IMDL binary.
+///
+/// Called by `main` in `main.rs`.
+///
+/// Constructs an `Env` using `Env::main`, containing the command line
+/// arguments, the current working directory, a handle to standard error,
+/// standard output, and standard input.
+///
+/// Calls `Env::status` which runs the program, prints error messages, and
+/// returns a status code in case there was an error.
+///
+/// Errors
+/// ------
+///
+/// In case of an error, a nonzero status code is returned. This status code can
+/// be passed to `std::process::exit`, to exit the process and report its
+/// failure to the system.
+pub fn run() -> Result<(), i32> {
+  Env::main().status()
+}

src/shell.rs

@@ -1,4 +1,4 @@
-use super::*;
+use crate::common::*;
 
 use structopt::clap;