Sessions
g1t-agent · merged · 11 entries · 3 tool calls
What happened
- Running on Claude Sonnet 5.5.
Prompt
You are a coding agent working in the git repository checked out in the current directory. Issue #22: Add a --times N flag that prints the greeting N times Add `pub times: usize` (default 1) to `Options` in `src/lib.rs`, set by `--times N` (the value is the next argument, which must not be mistaken for the name). On a missing or non-numeric value, print an error to stderr and exit with a non-zero status (parse_args may return a Result). In `src/main.rs`, print the greeting that many times, one per line, and combine correctly with `--shout`. Add unit tests for parsing (valid, missing value, non-number) and integration tests in `tests/cli.rs` running the binary with `--times 3 Ada` and with `--times 2 --shout Ada`. These commands must pass when you are done. Run them if the tools are installed: - cargo test - cargo run -- --times 3 Ada Make the change and keep it focused on the issue. Commit your work with a clear message. Do not push; that is done for you. Finish with a short summary of what you changed and why. It becomes the description of your pull request, so write it for a reviewer: plain sentences, no headings, no emoji, no checklists, and nothing about whether anything was committed or pushed. Say what you did not verify.
- Bash
cat src/lib.rs src/main.rs; ls tests; cat tests/cli.rs - Bash
python3 - <<'E' import re s=open('src/lib.rs').read() s=re.sub(r'parse_args\(args\((&\[[^\]]*\])\)\)',r'parse_args(args(\1)).unwrap()',s) s=s.replace('''#[derive(Debug, Default, PartialEq, Eq)] pub struct Options {''','''#[derive(Debug, PartialEq, Eq)] pub struct Options {''') s=s.replace(''' pub version: bool, } ''',''' pub version: bool, /// How many times to print the greeting (`--times N`). pub times: usize, } impl Default for Options { fn default() -> Self { Options { name: None, shout: false, version: false, times: 1, } } } ''',1) a=s.index('/// Parses command-line') b=s.index('/// `text` upper-cased') s=s[:a]+'''/// Parses command-line arguments (excluding the program name). /// /// `--shout` sets [`Options::shout`], `--version` sets /// [`Options::version`], and `--times N` sets [`Options::times`] (the /// next argument is consumed as the value); other arguments starting /// with `--` are treated as flags and skipped. The name is the first /// remaining argument. /// /// Returns an error message if `--times` has a missing or non-numeric value. pub fn parse_args<I: IntoIterator<Item = String>>(args: I) -> Result<Options, String> { let mut options = Options::default(); let mut args = args.into_iter(); while let Some(arg) = args.next() { if arg == "--shout" { options.shout = true; } else if arg == "--version" { options.version = true; } else if arg == "--times" { let value = args .next() .ok_or_else(|| "--times requires a value".to_owned())?; options.times = value .parse() .map_err(|_| format!("--times value must be a number, got {value:?}"))?; } else if !arg.starts_with("--") && options.name.is_none() { options.name = Some(arg); } } Ok(options) } '''+s[b:] s=s.replace(''' #[test] fn shout_upper_cases_greeting''',''' #[test] fn parse_args_times_defaults_to_one() { assert_eq!(parse_args(args(&["Ada"])).unwrap().times, 1); } #[test] fn parse_args_times_valid() { let options = parse_args(args(&["--times", "3", "Ada"])).unwrap(); assert_eq!(options.times, 3); assert_eq!(options.name.as_deref(), Some("Ada")); } #[test] fn parse_args_times_missing_value() { assert!(parse_args(args(&["--times"])).is_err()); } #[test] fn parse_args_times_non_number() { assert!(parse_args(args(&["--times", "abc", "Ada"])).is_err()); } #[test] fn shout_upper_cases_greeting''',1) open('src/lib.rs','w').write(s) m=open('src/main.rs').read() m=m.replace(''' let options = parse_args(env::args().skip(1)); ''',''' let options = match parse_args(env::args().skip(1)) { Ok(options) => options, Err(message) => { eprintln!("error: {message}"); process::exit(2); } }; ''').replace('use std::env;','use std::{env, process};') m=m.replace(''' println!("{}", if options.shout { shout(&message) } else { message });''',''' let line = if options.shout { shout(&message) } else { message }; for _ in 0..options.times { println!("{line}"); }''') open('src/main.rs','w').write(m) E cat >> tests/cli.rs <<'E' fn run(args: &[&str]) -> std::process::Output { Command::new(env!("CARGO_BIN_EXE_hello")) .args(args) .output() .unwrap() } #[test] fn times_prints_greeting_repeatedly() { let output = run(&["--times", "3", "Ada"]); assert!(output.status.success()); assert_eq!( String::from_utf8(output.stdout).unwrap(), "Hello, Ada!\n".repeat(3) ); } #[test] fn times_combines_with_shout() { let output = run(&["--times", "2", "--shout", "Ada"]); assert!(output.status.success()); assert_eq!( String::from_utf8(output.stdout).unwrap(), "HELLO, ADA!\n".repeat(2) ); } #[test] fn times_with_bad_value_fails() { let output = run(&["--times", "abc"]); assert!(!output.status.success()); assert!(!output.stderr.is_empty()); } E cargo test 2>&1 | tail -15; cargo run -q -- --times 3 Ada - Bash
cargo test 2>&1 | grep -E "test result|FAILED"; git commit -qam "Add --times N flag that prints the greeting N times" && echo ok I added a `--times N` flag that prints the greeting N times, one per line. It works together with `--shout`. `cargo test` passes, and `cargo run -- --times 3 Ada` prints `Hello, Ada!` three times. - **Parsing:** `Options` has a new `times: usize` field, defaulting to 1. `--times` takes the next argument as its value, so that value is never read as the name. - **Errors:** A missing or non-numeric value makes `parse_args` return an `Err`. `main` prints `error: ...` to stderr and exits with status 2. - **API change:** `parse_args` now returns `Result<Options, String>`, so I added `.unwrap()` to the existing parsing tests. - **Default impl:** `Options` now has a hand-written `Default`, because the derived one would have set `times` to 0. - **Tests:** The new unit tests cover the default, a valid value, a missing value and a non-number. The integration tests run `--times 3 Ada` and `--times 2 --shout Ada`. I also added one for a bad value, which checks for a non-zero exit and non-empty stderr. I did not check how `--times 0` behaves beyond the code: it prints nothing and exits successfully. I also did not check negative numbers, which fail to parse as `usize` and so are treated as errors.
- This run cost $0.0712 over 4 turns.
- Pushed b1c42490059b.