add chapter 3

Author: rakurame96

cli-book/Cargo.toml

@@ -4,4 +4,5 @@ resolver = "2"
 members = [ 
     "ch01_cli_rs", 
     "ch02_echor",
+    "ch03_catr",
 ]

cli-book/ch03_catr/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "ch03_catr"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+clap = "4.5.23"
+
+[dev-dependencies]
+assert_cmd = "2.0.13"
+predicates = "3.0.4"
+rand = "0.8"

cli-book/ch03_catr/mk-outs.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+set -u
+
+ROOT="tests/inputs"
+OUT_DIR="tests/expected"
+
+[[ ! -d "$OUT_DIR" ]] && mkdir -p "$OUT_DIR"
+
+EMPTY="$ROOT/empty.txt"
+FOX="$ROOT/fox.txt"
+SPIDERS="$ROOT/spiders.txt"
+BUSTLE="$ROOT/the-bustle.txt"
+ALL="$EMPTY $FOX $SPIDERS $BUSTLE"
+
+for FILE in $ALL; do
+    BASENAME=$(basename "$FILE")
+    cat    $FILE > ${OUT_DIR}/${BASENAME}.out
+    cat -n $FILE > ${OUT_DIR}/${BASENAME}.n.out
+    cat -b $FILE > ${OUT_DIR}/${BASENAME}.b.out
+done
+
+cat    $ALL > $OUT_DIR/all.out
+cat -n $ALL > $OUT_DIR/all.n.out
+cat -b $ALL > $OUT_DIR/all.b.out
+
+cat    < $BUSTLE > $OUT_DIR/$(basename $BUSTLE).stdin.out
+cat -n < $BUSTLE > $OUT_DIR/$(basename $BUSTLE).n.stdin.out
+cat -b < $BUSTLE > $OUT_DIR/$(basename $BUSTLE).b.stdin.out

cli-book/ch03_catr/src/lib.rs

@@ -0,0 +1,94 @@
+use std::error::Error;
+use clap::{Arg, ArgAction, Command};
+use std::fs::File;
+use std::io::{self, stdin, BufRead, BufReader};
+
+#[allow(unused)]
+#[derive(Debug)]
+pub struct Config {
+    files: Vec<String>,
+    number_lines: bool,
+    number_nonblank_lines: bool,
+}
+
+type MyResult<T> = Result<T, Box<dyn Error>>;
+
+fn open(filename: &str) -> MyResult<Box<dyn BufRead>> {
+    match filename {
+        "-" => Ok(Box::new(BufReader::new(io::stdin()))),
+        _ => Ok(Box::new(BufReader::new(File::open(filename)?))),
+    }
+}
+
+pub fn run(config: Config) -> MyResult<()> {
+    // dbg!(config);
+    for filename in config.files {
+        // println!("{}", filename);
+        match open(&filename) {
+            Err(err) => eprintln!("Failed to open {}: {}", filename, err),
+            Ok(_) => println!("Opened {}", filename),            
+        }
+    }
+    Ok(())
+} 
+
+pub fn get_args() -> MyResult<Config> {
+    let matches = Command::new("ch03_catr")
+        .version("0.1.0")
+        .author("Rakuram <[email protected]>")
+        .about("Rust cat Command")
+        .help_template(
+            "{name} {version} \n\
+             {author} \n\
+             {about} \n\n\
+             USAGE: \n    {usage}\n\n\
+             {all-args}",
+        )
+        .arg(
+            Arg::new("files")
+                .value_name("FILE")
+                .help("Input files")
+                // .required(true)          // reason why required is not used is because we are using default value
+                .num_args(1..)
+                .default_value("-")
+                .action(ArgAction::Append),
+        )
+        .arg(
+            Arg::new("number_lines")
+                .short('n')
+                .long("number")
+                .help("number all output lines")
+                .action(ArgAction::SetTrue)
+                .conflicts_with("number_nonblank"),
+        )
+        .arg(
+            Arg::new("number_nonblank")
+                .short('b')
+                .long("number-nonblank")
+                .help("number nonempty output lines, overrides -n")
+                .action(ArgAction::SetTrue),
+        )
+        .get_matches();
+
+    // let text: Vec<String> = matches
+    //     .get_many("files")
+    //     .expect("filename is required")
+    //     .cloned()
+    //     .collect();
+
+    // println!("{:#?}", text);
+
+    // let number_lines = matches.get_flag("number_lines");
+
+    // let number_nonblank_lines = matches.get_flag("number_nonblank_lines");
+
+    // println!("text: {:#?}", text);
+    // println!("number_lines: {:#?}", number_lines);
+    // println!("number_nonblank_lines: {:#?}", number_nonblank_lines);
+
+    Ok(Config {
+        files: matches.get_many("files").unwrap().cloned().collect(),
+        number_lines: matches.get_flag("number_lines"),
+        number_nonblank_lines: matches.get_flag("number_nonblank"),
+    })
+}

cli-book/ch03_catr/src/main.rs

@@ -0,0 +1,6 @@
+fn main() {
+    if let Err(e) = ch03_catr::get_args().and_then(ch03_catr::run) {
+        eprintln!("{}", e);
+        std::process::exit(1);
+    }
+}

cli-book/ch03_catr/tests/cli.rs

@@ -0,0 +1,3 @@
+     1	The quick brown fox jumps over the lazy dog.Don't worry, spiders,
+     2	I keep house 
+     3	casually.

cli-book/ch03_catr/tests/expected/all.b.out

@@ -0,0 +1,3 @@
+     1	The quick brown fox jumps over the lazy dog.Don't worry, spiders,
+     2	I keep house 
+     3	casually.

cli-book/ch03_catr/tests/expected/all.n.out

@@ -0,0 +1,3 @@
+The quick brown fox jumps over the lazy dog.Don't worry, spiders,
+I keep house 
+casually.