From c645b93899f74f809e0cf0d15bcc60412ec14d09 Mon Sep 17 00:00:00 2001
From: Danilo Bargen <mail@dbrgn.ch>
Date: Wed, 30 Dec 2015 08:49:37 +0100
Subject: [PATCH] Introduce optional logging

---
 Cargo.lock  | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  5 +++++
 README.md   | 14 ++++++++++++++
 src/main.rs | 16 ++++++++++++++++
 4 files changed, 90 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index 1411234..1e5b92e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3,6 +3,16 @@ name = "tldr"
 version = "0.1.0"
 dependencies = [
  "ansi_term 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "aho-corasick"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -10,3 +20,48 @@ name = "ansi_term"
 version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "env_logger"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.44 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "log"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "memchr"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
diff --git a/Cargo.toml b/Cargo.toml
index fa72330..bd61a84 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,5 +3,10 @@ name = "tldr"
 version = "0.1.0"
 authors = ["Danilo Bargen <mail@dbrgn.ch>"]
 
+[features]
+logging = ["env_logger"]
+
 [dependencies]
 ansi_term = "^0.7"
+log = "^0.3"
+env_logger = { version = "^0.3", optional = true }
diff --git a/README.md b/README.md
index f6f94cb..a0c1eeb 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,20 @@
 
 An implementation of [tldr](https://github.com/tldr-pages/tldr) in Rust.
 
+## Building
+
+Debug build with logging enabled:
+
+    $ cargo build --features logging
+
+Release build without logging:
+
+    $ cargo build --release
+
+To enable the log output, set the `RUST_LOG` env variable:
+
+    $ export RUST_LOG=tldr=debug
+
 ## License
 
 MIT
diff --git a/src/main.rs b/src/main.rs
index 187b90c..adb794a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,7 @@
+//! An implementation of [tldr](https://github.com/tldr-pages/tldr) in Rust.
+
+#[macro_use] extern crate log;
+#[cfg(feature = "logging")]extern crate env_logger;
 extern crate ansi_term;
 
 use std::io::BufReader;
@@ -20,8 +24,20 @@ fn get_file_reader(filepath: &str) -> Result<BufReader<File>, String> {
 }
 
 
+#[cfg(feature = "logging")]
+fn init_log() {
+    env_logger::init().unwrap();
+}
+
+#[cfg(not(feature = "logging"))]
+fn init_log() { }
+
+
 fn main() {
 
+    // Initialize logger
+    init_log();
+
     // Parse arguments
     let args: Vec<_> = env::args().collect();
     if args.len() != 2 {