feat: implement basic pattern matching

Cargo.lock

@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "1.0.0"
@@ -116,6 +125,12 @@ version = "1.70.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
 
+[[package]]
+name = "memchr"
+version = "2.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
+
 [[package]]
 name = "once_cell_polyfill"
 version = "1.70.2"
@@ -140,12 +155,42 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f020237b6c8eed93db2e2cb53c00c60a8e1bc73da7d073199a1180401450218d"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fcfdb36bda0c880c5931cdc7a2bcdc8ba4556847b9d912bca70bc94708711ad"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d6f6ff9a378485b298a5286656da665ba74413d36db0979633275d2e708145d4"
+
 [[package]]
 name = "smolgrep"
 version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
+ "regex",
 ]
 
 [[package]]

Cargo.toml

@@ -6,3 +6,4 @@ edition = "2024"
 [dependencies]
 anyhow = "1.0.104"
 clap = { version = "4.6.4", features = ["derive"] }
+regex = "1.13.1"

src/main.rs

@@ -11,10 +11,12 @@ fn main() -> anyhow::Result<()> {
     let cli = Cli::parse();
 
     let lines_iter = parser::read_lines(&cli.file_path)?;
-    parser::consume_lines(lines_iter);
+    let matches = parser::match_pattern(lines_iter, &cli.pattern);
 
     println!("Pattern: {}", cli.pattern);
     println!("File path: {}", cli.file_path);
+    println!("---");
+    println!("{:?}", matches);
 
     Ok(())
 }

src/parser.rs

@@ -4,6 +4,7 @@ use std::{
 };
 
 use anyhow::Context;
+use regex::Regex;
 
 pub fn read_lines(
     file_path: &str,
@@ -19,9 +20,14 @@ pub fn read_lines(
     Ok(reader.lines())
 }
 
-pub fn consume_lines(iter: impl Iterator<Item = std::io::Result<String>>) {
-    for line in iter {
-        let line = line.unwrap_or("".into());
-        println!("{line}");
-    }
+pub fn match_pattern(
+    iter: impl Iterator<Item = std::io::Result<String>>,
+    pattern: &str,
+) -> anyhow::Result<Vec<String>, anyhow::Error> {
+    let reg = Regex::new(pattern).with_context(|| format!("invalid regex: {:?}", pattern))?;
+    let lines = iter.collect::<std::io::Result<Vec<_>>>()?;
+
+    let matches = lines.into_iter().filter(|line| reg.is_match(line)).collect::<Vec<_>>();
+
+    Ok(matches)
 }