Added `GroupConfig` argument to `print_groups()`: Configurable group printing delimiters (default: Field delim (specified groups) <TAB>-literal, Line delim (input strings) <LF>-literal.)

This is to allow for supporting `-0` / `--field-delim=`-like cli flags.

Fortune for rematch's current commit: Half blessing − 半吉

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rematch"
-version = "1.1.0"
+version = "1.1.0+1"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2024"
 

src/main.rs

@@ -19,15 +19,88 @@ fn initialise() -> eyre::Result<()>
     Ok(())
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord/*, Copy*/)]
+pub struct GroupConfig<'a>
+{
+    pub line_delimiter: &'a [u8],
+    pub field_delimiter: &'a [u8],
+}
+
+impl<'a> Default for GroupConfig<'a>
+{
+    #[inline]
+    fn default() -> Self
+    {
+	Self::new()
+    }
+}
+
+impl<'a> GroupConfig<'a>
+{
+    pub const fn new() -> Self {
+	Self {
+	    line_delimiter: b"\n",
+	    field_delimiter: b"\t",
+	}
+    }
+
+    pub const fn has_line_delimiter(&self) -> bool {
+	! self.line_delimiter.is_empty()
+    }
+    pub const fn has_field_delimiter(&self) -> bool {
+	! self.field_delimiter.is_empty()
+    }
+    
+    #[inline] 
+    pub const fn with_field_delimiter<'b>(self, field_delimiter: &'b [u8]) -> GroupConfig<'b>
+    where 'a: 'b
+    {
+	GroupConfig {
+	    field_delimiter,
+	    ..self
+	}
+    }
+    #[inline] 
+    pub const fn with_field_delimiter_str<'b>(self, field: &'b str) -> GroupConfig<'b>
+    where 'a: 'b
+    {
+	GroupConfig {
+	    field_delimiter: field.as_bytes(),
+	    ..self
+	}
+    }
+    #[inline] 
+    pub const fn with_line_delimiter<'b>(self, line_delimiter: &'b [u8]) -> GroupConfig<'b>
+    where 'a: 'b
+    {
+	GroupConfig {
+	    line_delimiter,
+	    ..self
+	}
+    }
+    #[inline] 
+    pub const fn with_line_delimiter_str<'b>(self, line: &'b str) -> GroupConfig<'b>
+    where 'a: 'b
+    {
+	GroupConfig {
+	    line_delimiter: line.as_bytes(),
+	    ..self
+	}
+    }
+}
+
 #[inline] 
-fn print_groups<'a, S: ?Sized, G, T: 'a, I>(to: &mut S, g: G, groups: I) -> std::io::Result<()>
+fn print_groups<'c, 'a, S: ?Sized, G, T: 'a, I>(to: &mut S, g: G, groups: I, how: GroupConfig<'c>) -> std::io::Result<()>
 where S: std::io::Write,
       G: IntoIterator<Item = &'a Option<T>> + Clone + Copy, // NOTE: Copy bound to ensure we're not accidentally doing deep clones of `g`.
 //G: std::ops::Index<usize>, G::Output: std::borrow::Borrow<Option<T>>,
       T: std::borrow::Borrow<str>,
       I: IntoIterator<Item: std::borrow::Borrow<usize>/*, IntoIter: ExactSizeIterator*/>,
 {
-    use std::borrow::Borrow;
+    use std::{
+	borrow::Borrow,
+	io::Write,
+    };
     let mut first = true;
     for group in groups.into_iter() {
 	let group = group.borrow();
@@ -35,10 +108,13 @@ where S: std::io::Write,
 	// if !first {
 	//     write!(to, "\t")?;
 	// }
-	let print_delim = || first.then_some("").unwrap_or("\t"); // If it's not the first iteration, print `\t`.
+	let print_delim = move |to: &mut S| to.write_all(first.then_some(&[][..]).unwrap_or(&how.field_delimiter[..]).as_ref()); // If it's not the first iteration, print `\t`.
 	match g.into_iter().nth(*group) {
-	    Some(None) => write!(to, "{}", print_delim()),
-	    Some(Some(g)) => write!(to, "{}{}", print_delim(), g.borrow()),
+	    Some(None) => print_delim(to),
+	    Some(Some(g)) => {
+		print_delim(to)?;
+		write!(to, "{}", g.borrow())
+	    },
 
 	    //TODO: What should be the behaviour of a non-existent group index here? (NOTE: This now corresponds to the previous `g.len() > group` check in caller.) // (NOTE: The original behaviour is to just ignore groups that are out of range entirely (i.e. no printing, no delimit char, no error,) maybe treat non-existent groups as non-matched groups and *just* print the delim char?)
 	    // (NOTE: Moved out of branch, see above ^) // None if !first => write!(to, "\t"),
@@ -52,8 +128,8 @@ where S: std::io::Write,
 	first = false;
     }
     // If `first == true`, no groups were printed, so we do not print the new-line.
-    if !first {
-	to.write_all(b"\n")
+    if !first && !how.line_delimiter.is_empty() {
+	to.write_all(how.line_delimiter.as_ref())
     } else {
 	Ok(())
     }
@@ -78,21 +154,25 @@ fn main() -> eyre::Result<()>
 	let re = re::Regex::compile(&args[2])?;
 	let text = &args[1];
 
-	let groups = &args[3..];
+	let print_cfg = GroupConfig::new();
+	let groups = {
+	    let groups = &args[3..];
 
-	if groups.len() < 1 {
-	    eprintln!("Warning: No capture groups requested.");
-	    // NOTE: Unexpected branch...
-	    return Ok(());
-	}
+	    if groups.len() < 1 {
+		eprintln!("Warning: No capture groups requested.");
+		// NOTE: Unexpected branch...
+		return Ok(());
+	    }
 
-	let groups = groups.iter().enumerate()
-	    .map(|(i, x)| x.parse()
-		 .with_section(|| format!("{:?}", groups).header("Groups specified were"))
-		 .with_section(|| x.clone().header("Specified capture group index was"))
-		 .with_section(move || i.header("Argument index in provided groups")))
-	    .collect::<Result<Box<[usize]>, _>>()
-	    .wrap_err("Invalid group index specified")?;
+	    // Parse each group index into `groups`.
+	    groups.iter().enumerate()
+		.map(|(i, x)| x.parse()
+		     .with_section(|| format!("{:?}", groups).header("Groups specified were"))
+		     .with_section(|| x.clone().header("Specified capture group index was"))
+		     .with_section(move || i.header("Argument index in provided groups")))
+		.collect::<Result<Box<[usize]>, _>>()
+		.wrap_err("Invalid group index specified")?
+	};
 
 	//TODO: XXX: How to handle multiple groups in `stdin_lines()` case?
 	//let group = groups[0]; //args[3].parse().expect("Invalid group number.");
@@ -105,15 +185,14 @@ fn main() -> eyre::Result<()>
 		let mut stdout = stdout.lock();
 		match re.exec(&text)? {
 		    Some(g) /*if g.len() > group*/ => // NOTE: This check branch has now been moved into `print_groups()`
-			print_groups(&mut stdout, &g, &groups)?, //println!("{}", &g[group]),
+			print_groups(&mut stdout, &g, &groups, print_cfg.clone())?, //println!("{}", &g[group]),
 		    _ => (),
 		}
 		Ok(true)
 	    })?;
 	} else {
-
 	    match re.exec(&text)? {
-		Some(g) /*if g.len() > group*/ => print_groups(&mut stdout, &g[..], &groups)?,//println!("{}", &g.nth(group).unwrap().map(|x| x.as_ref()).unwrap_or("")),
+		Some(g) /*if g.len() > group*/ => print_groups(&mut stdout, &g[..], &groups, print_cfg)?,//println!("{}", &g.nth(group).unwrap().map(|x| x.as_ref()).unwrap_or("")),
 		_ => (),
 	    }
 	}