Software Tools

Rating:
Summary: Classic on software design
Review: Elsewhere on Amazon I reviewed Kernighan's "Elements of Programming Style." To quote one paragraph from that review -

Brian Kernighan has co-authored three books almost essential to learning our craft, this volume, "Software Tools" and "The Unix Programming Environment". "Elements of Programming Style" spells out the fundamental rules, "Software Tools" shows you how to apply them to a number of simple projects and extends the rules to software design and finally "The Unix Programming Environment" shows you how to use them in an operating system designed to reward you for your effort.

It could be said that "Elements" teaches programming and "Software Tools" teaches software design. Rules such as "do just one thing, do it well" seem to seep in through the pores as you read and work through this book.

It presents a number of projects starting with a word count program and progressing through some filters to some fairly complex tasks culminating in a RatFor pre-processor for Fortran. All the examples are written in RatFor, a version of Fortran that adds some more structured elements to that early language.

Don't be put off by the use of RatFor, the language is easily understood and the style of programming so clear that the algorithms are easily understood. I've personally translated a fair number of them to both BASIC and C and the RatFor pre-processor design became the basis for an AppleSoft BASIC pre-processor written by a close friend.

I've relied on this book so much for the last ten years, after writing "Hello World" I drag it out and translate a couple of the tools into every new language I've learnt. I then spend a day or two thinking about and implementing a design optimised for the new language. After that I find I have a good handle on a language and how to design for it.

This volume is not for those who want a book that gives them pre-written tools, a fair number of the tools are standard issue on any Unix derivative and the code is only tersely commented, relying on the exaplanatory text. However I recommend this book to all software designers and programmers because as you work through these examples you will learn a great deal about honing your craft.

Rating:
Summary: Disappointed
Review: My hopes were high because of the good reviews this book had received... I was disappointed. The idea of many simple programs, each with some clear functionality, that can be combined to produce powerful commands is illustrated clearly enough in the book. But the readability of the code leaves something to be desired. There are lots of if-the-else, while, and repeat constructs, and it's not possible to understand the code without the verbose explanations from the text. Often checking program behaviour for special cases, such as an empty file on input, are not part of the normal text, but left as excercises to the reader.

I would have liked concise comments that state invariants, pre-conditions, and post-conditions to illustrate the correctness of the program. These comments should be part of the program code, not some separate prose that is disconnected from the code. All too often have I had to support code without these comments, and without the accompanying prose to describe the code. This book seems to encourage writing such code.

And also the book is somewhat dated: some of the programs have functionality that made sense in the early days of FORTRAN programming, and are of little use to currentday C/C++ programmers.

Rating:
Summary: It's what's under the hood
Review: The tools you will find in this book are ancient. They're written in a cockeyed hybrid of C and Fortran, and they're almost hilariously user-hostile by modern definitions. If this intimidates you, look at it this way -- you're looking under the hood of modern applications. Much modern word processing, page layout, and language implementation can be built by putting a nice, shiny coating on what you find in this book.

Kernighan and Plauger set out in this book to document what they used in their labs at the time it was written, and show how to build them. Ratfor was chosen because C was not as widespread then as it is now, and for those who didn't have it, a translator to standard Fortran '77 was one of the major parts of the book. A simplified version of the nroff text formatter and a version of ed are also included for text file processing (then as now one of the major uses for computers), the result being both a toolkit and a practical education in the ins and outs of applications development.

The environment given is not Unix-based inherently, but this book is a natural companion to Kernighan and Rob Pike's The Unix Programming Environment and John Lions' Commentary on Unix 6th Edition. It should be required reading for anyone who wants to do software development.