minigrep/
lib.rs

1//! Useful for building a grep command line tool in rust
2use std::{fs,error::Error,env};
3
4///Config defines your data structure used in this application
5pub struct Config{
6    pub query:String,
7    pub file_path:String,
8    pub ignore_case:bool,
9}
10impl Config{
11    pub fn build(
12        mut args:impl Iterator<Item=String>,
13    )->Result<Self,&'static str>{
14
15        args.next();
16        let query=match args.next(){
17            Some(arg)=>arg,
18            None=> return Err("Query argument not provided"),
19        };
20        let file_path=match args.next(){
21            Some(arg)=>arg,
22            None=> return Err("Query argument not provided"),
23        };
24        let ignore_case=match args.next(){
25            Some(arg)=>arg=="true",
26            None=> env::var("IGNORE_CASE").is_ok(),
27        };
28        
29        Ok(Self{
30            query,
31            file_path,
32            ignore_case,
33        })
34    }
35}
36
37///used to search the file and print lines in that file that contains query string.
38
39pub fn run(config:Config)->Result<(),Box<dyn Error>>{
40    let contents=fs::read_to_string(config.file_path)?;
41    let res=if config.ignore_case{
42        search_case_insensitive(&config.query,&contents)
43    }else{
44        search(&config.query,&contents)
45    };
46
47    for x in res{
48        println!("{x}");
49    }
50    Ok(())
51}
52fn search<'a>(query:&str,content:&'a str)->Vec<&'a str>{
53    content
54        .lines()
55        .filter(|line| line.contains(&query))
56        .collect()
57}
58
59fn search_case_insensitive<'a>(query:&str,content:&'a str)->Vec<&'a str>{
60    let query=query.to_lowercase();
61    content
62        .lines()
63        .filter(|line| line.to_lowercase().contains(&query))
64        .collect()
65}
66
67#[cfg(test)]
68mod tests{
69    use super::*;
70
71    #[test]
72    fn case_sensitive(){
73        let query="Chinna";
74        let contents="\
75Chinna
76chinnachaitanya4037@gmail.com
779966547037
78B.Tech
79Gooty";
80        assert_eq!(vec!["Chinna"],search(query,contents));
81    }
82
83    #[test]
84    fn case_insensitive(){
85        let query="Chinna";
86        let contents="\
87Chinna
88chinnachaitanya4037@gmail.com
899966547037
90B.Tech
91Gooty";
92        assert_eq!(vec!["Chinna","chinnachaitanya4037@gmail.com"],search_case_insensitive(query,contents));
93    }
94}
minigrep/lib.rs

minigrep/
lib.rs
