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Showing posts from March, 2013

Automatic bookmarking of locations in Emacs

One of the things I find myself doing over and again in Emacs is returning to the last place I was editing a file. Sometimes that's because I've killed a buffer before I should have done (thinking I was finished), sometimes it's because I've exited Emacs and sometimes it's because I simply return to something a day or two later. Since it was incredibly annoying to have to search for the last place I was working I created a simple system in Emacs that automatically remembers where I was and then lets me jump there by hitting C-l (obviously you can choose whatever key binding you like, I choose that because I never use C-l for its real purpose). The automatic bookmarking works by using three Emacs hooks: when kill-buffer-hook or after-save-hook are called it records the current line number of the buffer in an internal hash table; when kill-emacs-hook is called it makes sure that the line number in each current buffer is saved and serializes the hash table to

A simple illustration of Go interfaces

Go 's approach to object orientation is somewhat different to the familiar 'hierarchy of classes'. In place of classes with methods, Go has interfaces . An interface specifies a set of behaviors (functions that can be called). If a Go type has that interface (i.e. has all the functions specified in the interface) then it can be used wherever that interface is required. A commonly used interface in Go is io.Writer . An io.Writer interface is defined as follows in the io package: type Writer interface { Write(p []byte) (n int, err error) } Any user-defined type that has a function with signature  Write(p []byte) (n int, err error) is an io.Writer and can be used wherever an io.Writer is needed. For example, the bufio package can be used to create a buffered version of any io.Writer by passing it to bufio.NewWriter . func NewWriter(wr io.Writer) *Writer bufio.NewWriter 's argument is itself an interface (an io.Writer ), so anything that has the  Write(p [

Some Pig

In the past I've written about writing . In my previous blog post I recommended three books: On Writing Well , by William Zinsser. This book is an example of its own title. It's a delightfully well written book about writing that reads with the slippery ease of a Malcolm Gladwell. It's both enjoyable and informative.  The AP Manual of Style . Although the AP book is about writing for newspapers it is full of useful advice about clarity. The fight for clarity is at the heart of non-fiction. Your goal is not to delight the reader with the breadth of your vocabulary, but to inform them about a subject in which you are claiming to be knowledgeable. News writing has to aim to be succinct, accessible and accurate; those are all good attributes for any non-fiction writing.  The Elements of Style , by Strunk and White. The surprising thing about Strunk and White is that I can pick it up after years and years of owning it and rediscover its lessons. If you only buy one