Add flag to use tabs instead of spaces

src/format.rs

@@ -20,7 +20,9 @@ pub fn format_file(
 ) -> String {
     record_file_log(logs, Info, file, "Formatting started.");
     let mut old_text = remove_extra_newlines(text);
-    old_text = remove_tabs(&old_text, args);
+    if !args.usetabs {
+        old_text = remove_tabs(&old_text, args);
+    }
     old_text = remove_trailing_spaces(&old_text);
 
     let mut state = State::new();

src/indent.rs

@@ -175,9 +175,13 @@ pub fn apply_indent(
         // apply indent
         new_line = line.trim_start().to_string();
         if !new_line.is_empty() {
-            let n_spaces = indent.visual * args.tab;
-            for _ in 0..n_spaces {
-                new_line.insert(0, ' ');
+            let n_indent_chars = indent.visual * args.tab;
+            for _ in 0..n_indent_chars {
+                if args.usetabs {
+                    new_line.insert(0, '\t');
+                } else {
+                    new_line.insert(0, ' ');
+                }
             }
         }
     }

src/parse.rs

@@ -40,6 +40,8 @@ pub struct Cli {
         default_value_t = 2
     )]
     pub tab: i8,
+    #[arg(long, help = "Use tabs instead of spaces for indentation")]
+    pub usetabs: bool,
 }
 
 impl Cli {
@@ -95,6 +97,7 @@ impl Cli {
             trace: false,
             files: Vec::<String>::new(),
             tab: 2,
+            usetabs: false,
         }
     }
 }