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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>{
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(args) => args ,
None => return Err("didn't get a file name")
};
let case_sensitive = env::var("CASE_INSENSITIVE").is_ok();
Ok(Config{query , filename , case_sensitive})
}
}
pub fn run(config: Config) -> Result<() , Box<dyn Error>>{
let contents = fs::read_to_string(config.filename)?;
let result = if config.case_sensitive{
search(&config.query , &contents)
}else {
search_case_insensitive(&config.query , &contents)
};
for line in result {
println!("{}" , line)
}
Ok(())
}
fn search<'a>(query: &'a str , contents: &'a str) -> Vec<&'a str>{
contents.lines()
.filter(|line|{
line.contains(query)
})
.collect()
}
fn search_case_insensitive<'a>(query: &str , contents: &'a str) -> Vec<&'a str>{
contents.lines()
.filter(|line|{
line.to_lowercase().contains(query.to_lowercase().as_str())
})
.collect()
}
#[cfg(test)]
mod tests{
use super::*;
#[test]
fn one_result(){
let query = "duct";
let contents = "\
Rust:
safe , fast , productive
pick thread
Duct tape";
assert_eq!(
vec!["safe , fast , productive"] ,
search(query , contents)
)
}
#[test]
fn case_sensitive(){
let query = "rUsT";
let contents = "\
Rust:
safe , fast , productive
pick three
Trust me";
assert_eq!(
vec!["Rust:" , "Trust me"] ,
search_case_insensitive(query , contents)
);
}
use std::thread;
use std::time::Duration;
#[test]
fn simulated_expensive_calculation(){
let s = sss{
name: 0,
};
}
struct sss{
pub name: u32,
}
impl Iterator for sss{
type Item = u32;
fn next(&mut self) -> Option<Self::Item> {
self.name += 1;
if self.name<6 {
Some(self.name)
}else {
None
}
}
}
}