v0.1.4: use stderr for error messages

Cargo.lock

@@ -0,0 +1,4 @@
+[[package]]
+name = "grep"
+version = "0.1.0"
+

README.md

@@ -31,4 +31,10 @@ History
 
 ```bash
 cargo init --bin --name grep
+cargo run
+
+git clone --depth=1 https://github.com/rust-lang/rust.vim.git ~/.vim/bundle/rust.vim
+git clone --depth=1 https://github.com/majutsushi/tagbar.git ~/.vim/bundle/tagbar
+echo 'let g:tagbar_ctags_bin = "/Users/aj/github.com/universal-ctags/ctags/ctags"' >> ~/.vimrc
+echo 'let g:rustfmt_autosave = 1' >> ~/.vimrc
 ```

poem.txt

@@ -0,0 +1,9 @@
+I'm nobody! Who are you?
+Are you nobody, too?
+Then there's a pair of us - don't tell!
+Theyd' banish us, you know.
+
+How dreary to be somebody!
+How public, like a frog
+To tell your name the livelong day
+To an admiring bog!

src/lib.rs

@@ -0,0 +1,100 @@
+use std::fs;
+//use std::fs::File;
+//use std::io::prelude::*;
+use std::error::Error;
+use std::env;
+
+pub struct Config {
+    query: String,
+    filename: String,
+    insensitive: bool,
+}
+
+pub fn run(conf: Config) -> Result<(), Box<dyn Error>> {
+    let contents = fs::read_to_string(conf.filename)?;
+
+    let results = if conf.insensitive {
+        search(&conf.query, &contents)
+    } else {
+        search_insensitive(&conf.query, &contents)
+    };
+
+    for line in results {
+        println!("{}", line);
+    }
+
+    Ok(())
+}
+
+fn search<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
+    let mut results = Vec::new();
+
+    for line in contents.lines() {
+        if line.contains(query) {
+          results.push(line);
+        }
+    }
+
+    results
+}
+
+fn search_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
+    let query = query.to_lowercase();
+    let mut results = Vec::new();
+
+    for line in contents.lines() {
+        if line.to_lowercase().contains(&query) {
+          results.push(line);
+        }
+    }
+
+    results
+}
+
+impl Config {
+    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+        if args.len() < 3 {
+            return Err("too few arguments")
+        }
+
+        Ok(Config {
+            query: args[1].clone(),
+            filename: args[2].clone(),
+            insensitive: env::var("CASE_INSENSITIVE").is_err(),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn case_sensitive() {
+        let query = "duct";
+        let contents = "\
+Rust:
+safe, fast, productive.
+Pick three.";
+
+        assert_eq!(
+            vec!["safe, fast, productive."],
+            search(query, contents)
+        );
+    }
+
+    #[test]
+    fn case_insensitive() {
+        let query = "rUsT";
+        let contents = "\
+Rust:
+safe, fast, productive.
+Pick three.
+Trust me.";
+
+        assert_eq!(
+            vec!["Rust:", "Trust me."],
+            search_insensitive(query, contents)
+        );
+    }
+}

src/main.rs

@@ -1,3 +1,22 @@
+extern crate grep;
+
+use std::env;
+use std::process;
+
 fn main() {
-    println!("Hello, world!");
+    let args: Vec<String> = env::args().collect();
+
+    let conf = grep::Config::new(&args).unwrap_or_else(|err| {
+        eprintln!("Problem parsing arguments: {}", err);
+        process::exit(1);
+    });
+    //let filename = &conf.filename.clone();
+
+    if let Err(e) = grep::run(conf) {
+        eprintln!("Big bad bada boom!\n{:?}", e);
+        //println!("Big bad bada boom!\n{:?}", e.kind());
+        //println!("Big bad bada boom!\n{}", e.description());
+
+        process::exit(1);
+    }
 }