Update manual page to use parameterized names

build.rs

@@ -1,7 +1,67 @@
 // TODO: Re-enable generation of shell completion files (below) when clap 3 is out.
 // For more details, see https://github.com/sharkdp/bat/issues/372
 
-fn main() {}
+#[macro_use]
+extern crate lazy_static;
+extern crate liquid;
+
+use std::error::Error;
+use std::fs;
+
+// Read environment variables.
+lazy_static! {
+    pub static ref PROJECT_NAME: &'static str = option_env!("PROJECT_NAME").unwrap_or("bat");
+    pub static ref PROJECT_VERSION: &'static str = option_env!("CARGO_PKG_VERSION").unwrap();
+    pub static ref EXECUTABLE_NAME: &'static str = option_env!("PROJECT_EXECUTABLE")
+        .or(option_env!("PROJECT_NAME"))
+        .unwrap_or("bat");
+}
+
+fn init_template() -> liquid::value::Object {
+    let mut globals = liquid::value::Object::new();
+
+    globals.insert(
+        "PROJECT_NAME".into(),
+        liquid::value::Value::scalar(PROJECT_NAME.to_owned()),
+    );
+
+    globals.insert(
+        "PROJECT_EXECUTABLE".into(),
+        liquid::value::Value::scalar(EXECUTABLE_NAME.to_owned()),
+    );
+
+    globals.insert(
+        "PROJECT_VERSION".into(),
+        liquid::value::Value::scalar(PROJECT_VERSION.to_owned()),
+    );
+
+    globals
+}
+
+/// Generates a file from a liquid template.
+fn template(
+    variables: &liquid::value::Object,
+    in_file: &str,
+    out_file: &str,
+) -> Result<(), Box<dyn Error>> {
+    let template = liquid::ParserBuilder::with_liquid()
+        .build()?
+        .parse(&fs::read_to_string(in_file)?)?;
+
+    fs::write(out_file, template.render(variables)?)?;
+    Ok(())
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let variables = init_template();
+    template(
+        &variables,
+        "assets/manual/bat.1.in",
+        &format!("assets/manual/{}.1", EXECUTABLE_NAME.to_owned()),
+    )?;
+
+    Ok(())
+}
 
 // #[macro_use]
 // extern crate clap;