Irreal

If you SSH into a remote system from within Emacs, you can have problems with the EDITOR environment variable on the remote system. This can arise when you invoke an application that calls the editor specified in EDITOR.

It turns out there’s an easy solution: the with-editor package can take care of this for you. If you’re using magit, you already have with-editor installed. If you’re not using magit, you can install with-editor from Melpa. Better yet, just install magit, you won’t be sorry. In any event, the details are in this very useful Emacs Stack Exchange entry.

If you’re a Tramp user, you really should take a look at the entry.

Recently I’ve written about Wilfred Hughes’ ht library for dealing with hash tables and Nic Ferrier’s kv library for dealing with alists and plists. Nicolas Petton commented that there is also the map library, which is built into Emacs as of version 25.2.

What makes Petton’s map library unique is that the functions will operate on alists, hash tables, or arrays so you don’t need to worry about separate functions for each data type. The functions do the expected things such as getting and putting values, mapping over key/value pairs, filtering, and so on.

Unfortunately, there doesn’t appear to be any documentation but it’s easy to look at the source to see what functions are available. The DOC strings do a good job of explaining what each function does.

If you have code that uses two or more of the supported data types, you should consider the map library. It provides a consistent set of functions that operate on them all. In particular, it makes it easy to change the data type of a variable because most of the code to manipulate it will be the same. As with the ht and kv libraries, the names of the functions and the ordering of the arguments are consistent and intuitive. That makes it easy to remember them.

The other day I wrote about Wilfred Hughes’ hash table library. In the comments, Noonian Atall remarked that Nic Ferrier also has a key/value library (kv) that’s worth taking a looking at.

Whereas Hughes’ ht library is primarily concerned with hash tables, Ferrier’s kv library deals primarily with alists, although it does provide functions for converting between alists and hash tables. As with the ht library, kv provides some naming consistency and saves writing simple conversion and access functions. If you work a lot with alists, you should take a look at this library and see if it can save you some time and work.