Bring back support for truncation with ellipsis

NEWS.md

@@ -4,10 +4,14 @@ swayr v0.13.0
 - The placeholders `{id}`, `{app_name}`, `{name}`/`{title}`, `{output_name}`,
   `{workspace_name}`, and `{marks}` may optionally provide a format string as
   specified by [Rust's std::fmt](https://doc.rust-lang.org/std/fmt/).  The
-  syntax is `{<placeholder>:<fmt_str>}`.  For example, `{app_name:{:>10.10}}`
-  would mean that the application name is printed with exactly 10 characters.
-  If it's shorter, it will be right-aligned (the `>`) and padded with spaces,
-  if it's longer, it'll be cut after the 10th character.
+  syntax is `{<placeholder>:<fmt_str>}` or `{<placeholder>:<fmt_str>…}`.  For
+  example, `{app_name:{:>10.10}}` would mean that the application name is
+  printed with exactly 10 characters.  If it's shorter, it will be
+  right-aligned (the `>`) and padded with spaces, if it's longer, it'll be cut
+  after the 10th character.  Another example, `{app_name:{:.10}…}` would mean
+  that the application name is truncated at 10 characters.  If it's shorter, it
+  will be printed as-is (no padding), if it's longer, it'll be cut after the
+  9th character and the ellipsis (…) character will be added after it.
 
 swayr v0.12.0
 =============

README.md

@@ -327,10 +327,14 @@ right now.
 The placeholders `{id}`, `{app_name}`, `{name}`/`{title}`, `{output_name}`,
 `{workspace_name}`, and `{marks}` may optionally provide a format string as
 specified by [Rust's std::fmt](https://doc.rust-lang.org/std/fmt/).  The syntax
-is `{<placeholder>:<fmt_str>}`.  For example, `{app_name:{:>10.10}}` would mean
-that the application name is printed with exactly 10 characters.  If it's
-shorter, it will be right-aligned (the `>`) and padded with spaces, if it's
-longer, it'll be cut after the 10th character.
+is `{<placeholder>:<fmt_str>}` or `{<placeholder>:<fmt_str>…}`.  For example,
+`{app_name:{:>10.10}}` would mean that the application name is printed with
+exactly 10 characters.  If it's shorter, it will be right-aligned (the `>`) and
+padded with spaces, if it's longer, it'll be cut after the 10th character.
+Another example, `{app_name:{:.10}…}` would mean that the application name is
+truncated at 10 characters.  If it's shorter, it will be printed as-is (no
+padding), if it's longer, it'll be cut after the 9th character and the ellipsis
+(…) character will be added after it.
 
 It is crucial that during selection (using wofi or some other menu program)
 each window has a different display string.  Therefore, it is highly

src/rtfmt.rs

@@ -73,11 +73,29 @@ impl<'a> std::convert::TryInto<usize> for &FmtArg<'a> {
     }
 }
 
-pub fn format(fmt: &str, arg: &str) -> String {
+pub fn format(fmt: &str, arg: &str, ellipsis: bool) -> String {
     let args = &[FmtArg::Str(arg)];
+
     if let Ok(pf) = ParsedFormat::parse(fmt, args, &NoNamedArguments) {
-        format!("{}", pf)
+        let mut s = format!("{}", pf);
+
+        if ellipsis && !s.contains(arg) {
+            s.pop();
+            s.push('…');
+        }
+        s
     } else {
         format!("Invalid format string: {}", fmt)
     }
 }
+
+#[test]
+fn test_format() {
+    assert_eq!(format("{:.10}", "sway", false), "sway");
+    assert_eq!(format("{:.10}", "sway", true), "sway");
+    assert_eq!(format("{:.4}", "𝔰𝔴𝔞𝔶", true), "𝔰𝔴𝔞𝔶");
+
+    assert_eq!(format("{:.3}", "sway", false), "swa");
+    assert_eq!(format("{:.3}", "sway", true), "sw…");
+    assert_eq!(format("{:.3}", "𝔰𝔴𝔞𝔶", true), "𝔰𝔴…");
+}

src/tree.rs

@@ -428,9 +428,10 @@ pub fn get_tree<'a>(
 lazy_static! {
     static ref APP_NAME_AND_VERSION_RX: regex::Regex =
         regex::Regex::new("(.+)(-[0-9.]+)").unwrap();
-    static ref PLACEHOLDER_RX: regex::Regex =
-        regex::Regex::new(r"\{(?P<name>[^}:]+)(?::(?P<fmtstr>\{[^}]*\}))?\}")
-            .unwrap();
+    static ref PLACEHOLDER_RX: regex::Regex = regex::Regex::new(
+        r"\{(?P<name>[^}:]+)(?::(?P<fmtstr>\{[^}]*\})(?P<ellipsis>…)?)?\}"
+    )
+    .unwrap();
 }
 
 fn maybe_html_escape(do_it: bool, text: String) -> String {
@@ -530,7 +531,12 @@ impl DisplayFormat for DisplayNode<'_> {
                     _ => caps[0].to_string(),
                 };
                 let fmt_str = caps.name("fmtstr").map_or("{}", |m| m.as_str());
-                maybe_html_escape(html_escape, rtfmt::format(fmt_str, &value))
+                let ellipsis = caps.name("ellipsis").is_some();
+
+                maybe_html_escape(
+                    html_escape,
+                    rtfmt::format(fmt_str, &value, ellipsis),
+                )
             })
             .into()
     }
@@ -561,3 +567,21 @@ impl DisplayFormat for DisplayNode<'_> {
         }
     }
 }
+
+#[test]
+fn test_placeholder_rx() {
+    let caps = PLACEHOLDER_RX.captures("Hello, {place}!").unwrap();
+    assert_eq!(caps.name("name").unwrap().as_str(), "place");
+    assert_eq!(caps.name("fmtstr"), None);
+    assert_eq!(caps.name("ellipsis"), None);
+
+    let caps = PLACEHOLDER_RX.captures("Hi, {place:{:>10.10}}!").unwrap();
+    assert_eq!(caps.name("name").unwrap().as_str(), "place");
+    assert_eq!(caps.name("fmtstr").unwrap().as_str(), "{:>10.10}");
+    assert_eq!(caps.name("ellipsis"), None);
+
+    let caps = PLACEHOLDER_RX.captures("Hello, {place:{:.5}…}!").unwrap();
+    assert_eq!(caps.name("name").unwrap().as_str(), "place");
+    assert_eq!(caps.name("fmtstr").unwrap().as_str(), "{:.5}");
+    assert_eq!(caps.name("ellipsis").unwrap().as_str(), "…");
+}