Ruby Best Practices

Chapter 4. Text Processing and File Management

Ruby fills a lot of the same roles that languages such as Perl and Python do. Because of this, you can expect to find first-rate support for text processing and file management. Whether it’s parsing a text file with some regular expressions or building some *nix-style filter applications, Ruby can help make life easier.

However, much of Ruby’s I/O facilities are tersely documented at best. It is also relatively hard to find good resources that show you general strategies for attacking common text-processing tasks. This chapter aims to expose you to some good tricks that you can use to simplify your text-processing needs as well as sharpen your skills when it comes to interacting with and managing files on your system.

As in other chapters, we’ll start off by looking at some real open source code—this time, a simple parser for an Adobe Font Metrics (AFM) file. This example will expose you to text processing in its setting. We’ll then follow up with a number of detailed sections that look at different practices that will help you master basic I/O skills. Armed with these techniques, you’ll be able to take on all sorts of text-processing and file-management tasks with ease.

Line-Based File Processing with State Tracking

Processing a text document line by line does not mean that we’re limited to extracting content in a uniform way, treating each line identically. Some files have more structure than that, but can still benefit from being processed ...