extract printing flags to a function

derive/src/help.rs

@@ -75,36 +75,7 @@ pub fn help_string(
     }
 
     let options = if !options.is_empty() {
-        let options = quote!([#(#options),*]);
-        quote!(
-            writeln!(w, "\nOptions:")?;
-            for (flags, help_string) in #options {
-                let indent = " ".repeat(#indent);
-
-                let mut help_lines = help_string.lines();
-                write!(w, "{}", &indent)?;
-                write!(w, "{}", &flags)?;
-
-                if flags.len() <= #width {
-                    let line = match help_lines.next() {
-                        Some(line) => line,
-                        None => {
-                            writeln!(w)?;
-                            continue;
-                        },
-                    };
-                    let help_indent = " ".repeat(#width-flags.len()+2);
-                    writeln!(w, "{}{}", help_indent, line)?;
-                } else {
-                    writeln!(w, "\n")?;
-                }
-
-                let help_indent = " ".repeat(#width+#indent+2);
-                for line in help_lines {
-                    writeln!(w, "{}{}", help_indent, line)?;
-                }
-            }
-        )
+        quote!(::uutils_args::print_flags(&mut w, #indent, #width, [#(#options),*])?;)
     } else {
         quote!()
     };

src/lib.rs

@@ -14,6 +14,7 @@ pub use value::{Value, ValueError, ValueResult};
 
 use std::{
     ffi::{OsStr, OsString},
+    io::Write,
     marker::PhantomData,
 };
 
@@ -316,6 +317,40 @@ pub fn filter_suggestions(input: &str, long_options: &[&str], prefix: &str) -> V
         .collect()
 }
 
+pub fn print_flags(
+    mut w: impl Write,
+    indent_size: usize,
+    width: usize,
+    options: impl IntoIterator<Item = (&'static str, &'static str)>,
+) -> std::io::Result<()> {
+    let indent = " ".repeat(indent_size);
+    writeln!(w, "\nOptions:")?;
+    for (flags, help_string) in options {
+        let mut help_lines = help_string.lines();
+        write!(w, "{}{}", &indent, &flags)?;
+
+        if flags.len() <= width {
+            let line = match help_lines.next() {
+                Some(line) => line,
+                None => {
+                    writeln!(w)?;
+                    continue;
+                }
+            };
+            let help_indent = " ".repeat(width - flags.len() + 2);
+            writeln!(w, "{}{}", help_indent, line)?;
+        } else {
+            writeln!(w)?;
+        }
+
+        let help_indent = " ".repeat(width + indent_size + 2);
+        for line in help_lines {
+            writeln!(w, "{}{}", help_indent, line)?;
+        }
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod test {
     use std::ffi::OsStr;