minigrep_tk 0.1.0

a simple grep application
Documentation 
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use std::error::Error;
use std::fs;
use std::env;


pub struct Config {
    pub query: String,
    pub filename: String,
    pub case_sensitive: bool,
}

impl Config {
    pub fn new(mut args: std::env::Args) -> Result<Config, &'static str> {
        if args.len() < 3 {
            return Err("not enough arguments");
        }
        args.next();
        let query = match args.next(){
            Some(arg)=>arg,
            None=>return Err("Didn't get a query string")
        };
        let filename = match args.next(){
            Some(arg)=>arg,
            None=>return Err("Didn't get a filename")
        };
        let case_sensitive = env::var("CASE_SENSITIVE").is_err();
        Ok(Config { query, filename, case_sensitive })
    }
}

pub fn run(config: Config) -> Result<(), Box<dyn Error>> {
    let contents = fs::read_to_string(config.filename)?;
    let results = if config.case_sensitive {
        search(&config.query, &contents)
    } else {
        search_case_insensitive(&config.query, &contents)
    };
    for line in results {
        println!("{}", line);
    }
    Ok(())
}

pub 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

    contents.lines().filter(|line|line.contains(query)).collect()
}

pub fn search_case_insensitive<'a>(query: &str, contents: &'a str) -> Vec<&'a str> {
    // let mut results = Vec::new();
    // let query = query.to_lowercase();
    // for line in contents.lines() {
    //     if line.to_lowercase().contains(&query) {
    //         results.push(line)
    //     }
    // }
    // results

    contents.lines().filter(|item|item.to_lowercase().contains(&query.to_lowercase())).collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn case_sensitive() {
        let query = "duct";
        let contents = "\
Rust:
safe,fast,productive.
Pick three.
Duct tape.";
        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_case_insensitive(query, contents))
    }
}