First commit.

lisp/lib/utils.el

@@ -0,0 +1,51 @@
+;;; utils.el --- miscellaneous support functions -*- lexical-binding: t; -*-
+;;; Commentary:
+;;; Code:
+
+(defmacro try-eval (fn &optional finally)
+  "Safely evaluate expression FN and run FINALLY after."
+  (declare (debug t)
+           (indent 1))
+  `(let (retval)
+     (condition-case-unless-debug ex
+         (setq retval (progn ,fn))
+       ('error
+        (setq retval (cons 'exception (list ex)))))
+     ,@finally
+     retval))
+
+
+(defun feature-p (feature)
+  "Check if FEATURE is available."
+  (or (featurep feature)
+      (when (functionp 'package-installed-p)
+        (package-installed-p feature))
+      (locate-library (symbol-name feature))))
+
+
+(defun add-command-switch (handler &rest switch-list)
+  "Add HANDLER for SWITCH-LIST."
+  (dolist (switch switch-list)
+    (add-to-list 'command-switch-alist (cons switch handler))))
+
+
+(defun add-auto-mode (mode &rest patterns)
+  "Use `MODE' for all given files matching `PATTERNS'."
+  (dolist (pattern patterns)
+    (add-to-list 'auto-mode-alist (cons pattern mode))))
+
+
+(defun add-magic-mode (mode &rest patterns)
+  "Use `MODE' for all files containing header `PATTERNS'."
+  (dolist (pattern patterns)
+    (add-to-list 'magic-mode-alist (cons pattern mode))))
+
+
+(defun add-interpreter-mode (mode &rest interpreters)
+  "Use `MODE' for all files with shebang `INTERPRETERS'."
+  (dolist (interpreter interpreters)
+    (add-to-list 'interpreter-mode-alist (cons interpreter mode))))
+
+
+(provide 'lib/utils)
+;;; utils.el ends here