diff --git a/src/fmt_replace.rs b/src/fmt_replace.rs
index 58d1870..38f4e67 100644
--- a/src/fmt_replace.rs
+++ b/src/fmt_replace.rs
@@ -41,14 +41,14 @@ macro_rules! fmt_replace {
                 let value: String = match &caps["name"] {
                     $(
                         $( | $pat )+ => {
-                            let val = $exp;
+                            let val = $crate::rtfmt::FmtArg::from($exp);
                             let fmt_str = caps.name("fmtstr")
                                 .map_or("{}", |m| m.as_str());
                             let clipped_str = caps.name("clipstr")
                                 .map_or("", |m| m.as_str());
                             $crate::fmt_replace::maybe_html_escape(
                                 $html_escape,
-                                crate::rtfmt::format(fmt_str, &val, clipped_str),
+                                $crate::rtfmt::format(fmt_str, val, clipped_str),
                             )
                         }
                     )+
diff --git a/src/rtfmt.rs b/src/rtfmt.rs
index cc5c5e6..989bf1b 100644
--- a/src/rtfmt.rs
+++ b/src/rtfmt.rs
@@ -22,18 +22,47 @@ use rt_format::{
 };
 use std::fmt;
 
-enum FmtArg<'a> {
-    Str(&'a str),
+pub enum FmtArg {
+    I64(i64),
+    String(String),
 }
 
-impl<'a> FormatArgument for FmtArg<'a> {
+impl From<i64> for FmtArg {
+    fn from(x: i64) -> FmtArg {
+        FmtArg::I64(x)
+    }
+}
+
+impl From<&str> for FmtArg {
+    fn from(x: &str) -> FmtArg {
+        FmtArg::String(x.to_string())
+    }
+}
+
+impl From<String> for FmtArg {
+    fn from(x: String) -> FmtArg {
+        FmtArg::String(x)
+    }
+}
+
+impl ToString for FmtArg {
+    fn to_string(&self) -> String {
+        match self {
+            FmtArg::String(x) => x.clone(),
+            FmtArg::I64(x) => x.to_string(),
+        }
+    }
+}
+
+impl FormatArgument for FmtArg {
     fn supports_format(&self, spec: &Specifier) -> bool {
         spec.format == Format::Display
     }
 
     fn fmt_display(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            Self::Str(val) => fmt::Display::fmt(&val, f),
+            Self::String(val) => fmt::Display::fmt(&val, f),
+            Self::I64(val) => fmt::Display::fmt(&val, f),
         }
     }
 
@@ -66,13 +95,13 @@ impl<'a> FormatArgument for FmtArg<'a> {
     }
 }
 
-pub fn format(fmt: &str, arg: &str, clipped_str: &str) -> String {
-    let args = &[FmtArg::Str(arg)];
+pub fn format(fmt: &str, arg: FmtArg, clipped_str: &str) -> String {
+    let arg_string = arg.to_string();
 
-    if let Ok(pf) = ParsedFormat::parse(fmt, args, &NoNamedArguments) {
+    if let Ok(pf) = ParsedFormat::parse(fmt, &[arg], &NoNamedArguments) {
         let mut s = format!("{}", pf);
 
-        if !clipped_str.is_empty() && !s.contains(arg) {
+        if !clipped_str.is_empty() && !s.contains(arg_string.as_str()) {
             remove_last_n_chars(&mut s, clipped_str.chars().count());
             s.push_str(clipped_str);
         }
diff --git a/src/tree.rs b/src/tree.rs
index 7b9b181..bdb352e 100644
--- a/src/tree.rs
+++ b/src/tree.rs
@@ -465,7 +465,10 @@ impl DisplayFormat for DisplayNode<'_> {
             Type::Window => cfg.get_format_window_format(),
         };
         let fmt = fmt
-            .replace("{indent}", &indent.repeat(self.get_indent_level()))
+            .replace(
+                "{indent}",
+                indent.repeat(self.get_indent_level()).as_str(),
+            )
             .replace(
                 "{urgency_start}",
                 if self.node.urgent {
@@ -501,20 +504,18 @@ impl DisplayFormat for DisplayNode<'_> {
             );
 
         fmt_replace!(&fmt, html_escape, {
-            "id" => self.node.id.to_string(),
-            "app_name" => self.node.get_app_name().to_string(),
+            "id" => self.node.id,
+            "app_name" => self.node.get_app_name(),
             "layout" => format!("{:?}", self.node.layout),
-            "name" | "title" => self.node.get_name().to_string(),
+            "name" | "title" => self.node.get_name(),
             "output_name" => self
                 .tree
                 .get_parent_node_of_type(self.node.id, Type::Output)
-                .map_or("<no_output>", |w| w.get_name())
-                .to_string(),
+                .map_or("<no_output>", |w| w.get_name()),
             "workspace_name" => self
                 .tree
                 .get_parent_node_of_type(self.node.id, Type::Workspace)
-                .map_or("<no_workspace>", |w| w.get_name())
-                .to_string(),
+                .map_or("<no_workspace>", |w| w.get_name()),
             "marks" => format_marks(&self.node.marks),
         })
     }