Move print_versions into a util crate.

src/util/mod.rs

@@ -0,0 +1,47 @@
+use tokio::process::Command;
+
+pub(crate) async fn print_versions() -> Result<(), Box<dyn std::error::Error>> {
+    eprintln!("Using emacs version: {}", get_emacs_version().await?.trim());
+    eprintln!(
+        "Using org-mode version: {}",
+        get_org_mode_version().await?.trim()
+    );
+    Ok(())
+}
+
+pub(crate) async fn get_emacs_version() -> Result<String, Box<dyn std::error::Error>> {
+    let elisp_script = r#"(progn
+     (message "%s" (version))
+)"#;
+    let mut cmd = Command::new("emacs");
+    let cmd = cmd
+        .arg("-q")
+        .arg("--no-site-file")
+        .arg("--no-splash")
+        .arg("--batch")
+        .arg("--eval")
+        .arg(elisp_script);
+
+    let out = cmd.output().await?;
+    out.status.exit_ok()?;
+    Ok(String::from_utf8(out.stderr)?)
+}
+
+pub(crate) async fn get_org_mode_version() -> Result<String, Box<dyn std::error::Error>> {
+    let elisp_script = r#"(progn
+     (org-mode)
+     (message "%s" (org-version nil t nil))
+)"#;
+    let mut cmd = Command::new("emacs");
+    let cmd = cmd
+        .arg("-q")
+        .arg("--no-site-file")
+        .arg("--no-splash")
+        .arg("--batch")
+        .arg("--eval")
+        .arg(elisp_script);
+
+    let out = cmd.output().await?;
+    out.status.exit_ok()?;
+    Ok(String::from_utf8(out.stderr)?)
+}