Move backslash escaping to separate crate

Cargo.lock

@@ -29,6 +29,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "backslash"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35a89ea09f2c7f3c81711c0db7d389d86a9d66fa15a7067e6fd6dbef863ef786"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -39,6 +45,7 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 name = "choose"
 version = "1.2.0"
 dependencies = [
+ "backslash",
  "lazy_static",
  "regex",
  "structopt",

Cargo.toml

@@ -19,3 +19,4 @@ exclude = [
 structopt = "0.3"
 regex = "1"
 lazy_static = "1"
+backslash = "0"

src/escape.rs

@@ -1,137 +1 @@
-pub fn process_escapes(input: &str) -> String {
-    if input.len() < 1 {
-        return String::from(input);
-    }
 
-    let mut v = Vec::from(input);
-    for i in 0..(v.len() - 1) {
-        if v[i] == '\\' as u8 && is_escapable(v[i + 1] as char) {
-            v.remove(i);
-            v[i] = char_to_escape_sequence(v[i] as char) as u8;
-        }
-    }
-    String::from_utf8(v).unwrap()
-}
-
-fn char_to_escape_sequence(chr: char) -> char {
-    match chr {
-        'n' => '\n',
-        't' => '\t',
-        'r' => '\r',
-        '\\' => '\\',
-        '0' => '\0',
-        _ => chr,
-    }
-}
-
-fn is_escapable(chr: char) -> bool {
-    match chr {
-        'n' | 't' | 'r' | '\\' | '0' => true,
-        _ => false,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    mod test_process_escapes {
-        use super::*;
-
-        #[test]
-        fn test_newline() {
-            assert_eq!(
-                String::from("hello\nworld"),
-                process_escapes(r#"hello\nworld"#)
-            );
-        }
-
-        #[test]
-        fn test_carriage_return() {
-            assert_eq!(
-                String::from("hello\rworld"),
-                process_escapes(r#"hello\rworld"#)
-            );
-        }
-
-        #[test]
-        fn test_tab() {
-            assert_eq!(
-                String::from("hello\tworld"),
-                process_escapes(r#"hello\tworld"#)
-            );
-        }
-
-        #[test]
-        fn test_backslash() {
-            assert_eq!(
-                String::from("hello\\world"),
-                process_escapes(r#"hello\\world"#)
-            );
-        }
-
-        #[test]
-        fn test_null() {
-            assert_eq!(
-                String::from("hello\0world"),
-                process_escapes(r#"hello\0world"#)
-            );
-        }
-    }
-
-    mod test_char_to_escape_sequence {
-        use super::*;
-        #[test]
-        fn test_escape_n() {
-            assert_eq!('\n', char_to_escape_sequence('n'));
-        }
-
-        #[test]
-        fn test_escape_t() {
-            assert_eq!('\t', char_to_escape_sequence('t'));
-        }
-
-        #[test]
-        fn test_escape_r() {
-            assert_eq!('\r', char_to_escape_sequence('r'));
-        }
-
-        #[test]
-        fn test_escape_backslash() {
-            assert_eq!('\\', char_to_escape_sequence('\\'));
-        }
-
-        #[test]
-        fn test_escape_0() {
-            assert_eq!('\0', char_to_escape_sequence('0'));
-        }
-    }
-
-    mod is_escapable_tests {
-        use super::*;
-
-        #[test]
-        fn test_escape_n() {
-            assert!(is_escapable('n'));
-        }
-
-        #[test]
-        fn test_escape_t() {
-            assert!(is_escapable('t'));
-        }
-
-        #[test]
-        fn test_escape_r() {
-            assert!(is_escapable('r'));
-        }
-
-        #[test]
-        fn test_escape_backslash() {
-            assert!(is_escapable('\\'));
-        }
-
-        #[test]
-        fn test_escape_0() {
-            assert!(is_escapable('0'));
-        }
-    }
-}

src/opt.rs

@@ -2,7 +2,6 @@ use std::path::PathBuf;
 use structopt::StructOpt;
 
 use crate::choice::Choice;
-use crate::escape;
 use crate::parse;
 
 #[derive(Debug, StructOpt)]
@@ -38,7 +37,7 @@ pub struct Opt {
     pub one_indexed: bool,
 
     /// Specify output field separator
-    #[structopt(short, long, parse(from_str = escape::process_escapes))]
+    #[structopt(short, long, parse(from_str = parse::output_field_separator))]
     pub output_field_separator: Option<String>,
 
     /// Fields to print. Either a, a:b, a..b, or a..=b, where a and b are integers. The beginning

src/parse.rs

@@ -1,3 +1,4 @@
+use backslash::escape_ascii;
 use regex::Regex;
 
 use crate::choice::{Choice, ChoiceKind};
@@ -60,6 +61,10 @@ pub fn choice(src: &str) -> Result<Choice, ParseError> {
     return Ok(Choice::new(start, end, kind));
 }
 
+pub fn output_field_separator(src: &str) -> String {
+    escape_ascii(src).unwrap()
+}
+
 #[cfg(test)]
 mod tests {
     use crate::parse;