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@Muddledde
Description
First, thank you for taking the time to create this guide (and reading this). :-)
It was my understanding from the beginning that the guide would guide one towards creating a simple Command Line App, but after 1.4 there doesn't appear to be much cohesion. I assume I am missing something here, but 1.5 (and further) changes main.rs in a way that it doesn't appear to function around the same logic built/defined before 1.4.
#![allow(unused)]
use clap::Parser;
/// Search for a pattern in a file and display the lines that contain it.
#[derive(Parser)]
struct Cli {
/// The pattern to look for
pattern: String,
/// The path to the file to read
path: std::path::PathBuf,
}
fn main() {
let args = Cli::parse();
let content = std::fs::read_to_string(&args.path).expect("could not read file");
for line in content.lines() {
if line.contains(&args.pattern) {
println!("{}", line);
}
}
}
use anyhow::{Context, Result};
fn main() -> Result<()> {
let path = "test.txt";
let content = std::fs::read_to_string(path)
.with_context(|| format!("could not read file `{}`", path))?;
println!("file content: {}", content);
Ok(())
}
1.5 gives an example of a bunch of nice tools to add (such as logging and progress bars), but as mentioned earlier, there is no cohesion with the early development; no addition to the previously constructed chapters.
Printer Performance
#![allow(unused)]
fn main() {
use std::io::{self, Write};
let stdout = io::stdout(); // get the global stdout entity
let mut handle = stdout.lock(); // acquire a lock on it
writeln!(handle, "foo: {}", 42); // add `?` if you care about errors here
}
Progress Bar
fn main() {
let pb = indicatif::ProgressBar::new(100);
for i in 0..100 {
do_hard_work();
pb.println(format!("[+] finished #{}", i));
pb.inc(1);
}
pb.finish_with_message("done");
}
Logging
use log::{info, warn};
fn main() {
env_logger::init();
info!("starting up");
warn!("oops, nothing implemented!");
}