Add extension placeholder

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Features
 - Add `--ignore-parent` option to override `--no-ignore-parent`, see #1958 (@tmchow)
 - Add `--exact` option to match the entire filename exactly (literal, non-substring).
+- Add `{.ext}` placeholder for file extensions in `--format`, `--exec`, and `--exec-batch`, see #1818 (@puneetdixit200).
 
 ## Bugfixes
 - Handle invalid working directories gracefully when using `--full-path`, see #1900 (@Xavrir).

src/cli.rs

@@ -476,6 +476,7 @@ pub struct Opts {
     ///   '{/}': basename
     ///   '{//}': parent directory
     ///   '{.}': path without file extension
+    ///   '{.ext}': file extension
     ///   '{/.}': basename without file extension
     #[arg(
         long,
@@ -901,6 +902,7 @@ impl clap::Args for Exec {
                        '{/}':  basename\n  \
                        '{//}': parent directory\n  \
                        '{.}':  path without file extension\n  \
+                       '{.ext}': file extension\n  \
                        '{/.}': basename without file extension\n  \
                        '{{':   literal '{' (for escaping)\n  \
                        '}}':   literal '}' (for escaping)\n\n\
@@ -936,6 +938,7 @@ impl clap::Args for Exec {
                        '{/}':  basename\n  \
                        '{//}': parent directory\n  \
                        '{.}':  path without file extension\n  \
+                       '{.ext}': file extension\n  \
                        '{/.}': basename without file extension\n  \
                        '{{':   literal '{' (for escaping)\n  \
                        '}}':   literal '}' (for escaping)\n\n\

src/exec/mod.rs

@@ -315,6 +315,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn tokens_with_extension() {
+        assert_eq!(
+            CommandSet::new(vec![vec!["echo", "{.ext}"]]).unwrap(),
+            CommandSet {
+                commands: vec![CommandTemplate {
+                    args: vec![
+                        FormatTemplate::Text("echo".into()),
+                        FormatTemplate::Tokens(vec![Token::Extension]),
+                    ],
+                }],
+                mode: ExecutionMode::OneByOne,
+            }
+        );
+    }
+
     #[test]
     fn tokens_with_basename() {
         assert_eq!(

src/fmt/input.rs

@@ -18,6 +18,11 @@ pub fn remove_extension(path: &Path) -> OsString {
     strip_current_dir(&path).to_owned().into_os_string()
 }
 
+/// Returns the extension of the path.
+pub fn extension(path: &Path) -> &OsStr {
+    path.extension().unwrap_or_default()
+}
+
 /// Removes the basename from the path.
 pub fn dirname(path: &Path) -> OsString {
     path.parent()
@@ -60,6 +65,12 @@ mod path_tests {
         remove_ext_utf8:    remove_extension  for  "💖.txt"       =>  "💖"
         remove_ext_empty:   remove_extension  for  ""             =>  ""
 
+        extension_simple:  extension  for  "foo.txt"      =>  "txt"
+        extension_dir:     extension  for  "dir/foo.txt"  =>  "txt"
+        extension_hidden:  extension  for  ".foo"         =>  ""
+        extension_no_ext:  extension  for  "foo"          =>  ""
+        extension_utf8:    extension  for  "dir/foo.💖"   =>  "💖"
+
         basename_simple:  basename  for  "foo.txt"      =>  "foo.txt"
         basename_dir:     basename  for  "dir/foo.txt"  =>  "foo.txt"
         basename_empty:   basename  for  ""             =>  ""

src/fmt/mod.rs

@@ -8,7 +8,7 @@ use std::sync::OnceLock;
 
 use aho_corasick::AhoCorasick;
 
-use self::input::{basename, dirname, remove_extension};
+use self::input::{basename, dirname, extension, remove_extension};
 
 /// Designates what should be written to a buffer
 ///
@@ -20,6 +20,7 @@ pub enum Token {
     Basename,
     Parent,
     NoExt,
+    Extension,
     BasenameNoExt,
     Text(String),
 }
@@ -31,6 +32,7 @@ impl Display for Token {
             Token::Basename => f.write_str("{/}")?,
             Token::Parent => f.write_str("{//}")?,
             Token::NoExt => f.write_str("{.}")?,
+            Token::Extension => f.write_str("{.ext}")?,
             Token::BasenameNoExt => f.write_str("{/.}")?,
             Token::Text(ref string) => f.write_str(string)?,
         }
@@ -62,7 +64,7 @@ impl FormatTemplate {
         let mut remaining = fmt;
         let mut buf = String::new();
         let placeholders = PLACEHOLDERS.get_or_init(|| {
-            AhoCorasick::new(["{{", "}}", "{}", "{/}", "{//}", "{.}", "{/.}"]).unwrap()
+            AhoCorasick::new(["{{", "}}", "{}", "{/}", "{//}", "{.}", "{.ext}", "{/.}"]).unwrap()
         });
         while let Some(m) = placeholders.find(remaining) {
             match m.pattern().as_u32() {
@@ -127,6 +129,9 @@ impl FormatTemplate {
                             &remove_extension(path),
                             path_separator,
                         )),
+                        Extension => {
+                            s.push(Self::replace_separator(extension(path), path_separator))
+                        }
                         Parent => s.push(Self::replace_separator(&dirname(path), path_separator)),
                         Placeholder => {
                             s.push(Self::replace_separator(path.as_ref(), path_separator))
@@ -205,7 +210,8 @@ fn token_from_pattern_id(id: u32) -> Token {
         3 => Basename,
         4 => Parent,
         5 => NoExt,
-        6 => BasenameNoExt,
+        6 => Extension,
+        7 => BasenameNoExt,
         _ => unreachable!(),
     }
 }
@@ -242,6 +248,7 @@ mod fmt_tests {
             basename={/} \
             parent={//} \
             noExt={.} \
+            ext={.ext} \
             basenameNoExt={/.} \
             }}",
         );
@@ -256,6 +263,8 @@ mod fmt_tests {
                 Parent,
                 Text(" noExt=".into()),
                 NoExt,
+                Text(" ext=".into()),
+                Extension,
                 Text(" basenameNoExt=".into()),
                 BasenameNoExt,
                 Text(" }".into()),
@@ -275,7 +284,22 @@ mod fmt_tests {
             basename=file.txt \
             parent=a/folder \
             noExt=a/folder/file \
+            ext=txt \
             basenameNoExt=file }"
         );
     }
+
+    #[test]
+    fn extension_placeholder() {
+        let templ = FormatTemplate::parse("extension={.ext}");
+
+        let mut path = PathBuf::new();
+        path.push("a");
+        path.push("folder");
+        path.push("file.txt");
+
+        let expanded = templ.generate(&path, Some("/")).into_string().unwrap();
+
+        assert_eq!(expanded, "extension=txt");
+    }
 }

tests/tests.rs

@@ -1701,6 +1701,16 @@ fn format() {
         noExt=one/two/three/directory_foo",
     );
 
+    te.assert_output(
+        &["foo", "--format", "extension={.ext}", "--path-separator=/"],
+        "extension=foo
+        extension=foo
+        extension=Foo2
+        extension=foo
+        extension=foo
+        extension=",
+    );
+
     te.assert_output(
         &["foo", "--format", "basename={/}", "--path-separator=/"],
         "basename=a.foo
@@ -1781,6 +1791,16 @@ fn test_exec() {
             one/two/three/directory_foo",
         );
 
+        te.assert_output(
+            &["foo", "--exec", "echo", "{.}_encoded.{.ext}"],
+            "a_encoded.foo
+            one/b_encoded.foo
+            one/two/C_encoded.Foo2
+            one/two/c_encoded.foo
+            one/two/three/d_encoded.foo
+            one/two/three/directory_foo_encoded.",
+        );
+
         te.assert_output(
             &["foo", "--exec", "echo", "{/}"],
             "a.foo