---
title: How to Extract an Intention-Revealing Name Using Vim
teaser:
tags: good code,vim
author: Joe Ferris
published_on: 2012-05-02
---

This method has a [magic number](http://c2.com/cgi/wiki?MagicNumber):

    def wait_time
      @env[QUEUE_WAIT_HEADER].to_i / 1000
    end

Let's extract that to an [intention-revealing
name](http://c2.com/cgi/wiki?IdentifiersRevealIntent). We'll type:

    /1000<Enter>                   # Find the number we want to extract
    cwmilliseconds_per_second<Esc> # Replace the number with a variable name
    O<Ctrl+A> = <Esc>p             # Assign the replaced number to the variable

The result:

    def wait_time
      milliseconds_per_second = 1000
      @env[QUEUE_WAIT_HEADER].to_i / milliseconds_per_second
    end

Under the covers:

* `<Ctrl+A>` inserts the last text you typed in insert mode, so the variable
  name is available after replacing the number
* Replacing or deleting text in Vim will place that text in your default
  buffer, so the number is available to put at the end

Assuming your cursor is at the value you want to extract, this creates an
intention revealing name in 10 keystrokes, plus the keystrokes it takes to type
out the name.

Can you beat my Vim golf?