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Regular Expression Recipes
Regular expressions are not restricted to just the Perl or shell environments, so Nathan offers variations for Python, PHP, and VIM as well. In most cases the translation is relatively straight-forward, but in a few cases a different environment may have (or lack) additional facilities, prompting a different expression to do the same task.
Before you even read chapter 1, Nathan provides a quick summary course on regular expressions, with detail given to each of the five environments you might utilize. He has written the syntax overview in a highly-readable format, making it easy to understand the gobbledy-gook of the most bizarre concoctions you might encounter.
The first chapter (Words and Text) starts simply enough. He gives examples of how to find single words, multiple words, and repeated words, along with examples of how to replace various detected strings with others. In each case he gives an example of its use for each platform, followed by a bit-by-bit breakdown of how it works. Not every environment is given on every example, and in many cases the "How It Works" section refers to the first one, as most REs are identical between the platforms.
The next chapter (URLs and Paths) offers various methods of doing commonly needed parsing. Pulling out file names, query strings, and directories, as well as reconstructing them in useful fashions is covered in the 15 offerings given here. Validating, converting, and extracting fields of CSV and tab-delimited files are handled in chapter 3, while chapter 4 is concerned with validating field formats, as well as re-formatting text for the fields. Chapter 5 handles similar tasks for HTML and XML documents. The final chapter covers expressions that facilitate the management of program code, log files, and the output of selected commands.
First, I must admit that there are a number of useful solutions provided, especially for someone who is concerned with application and web development. However, I did feel a little cheated by the fact that several chapters covered essentially the same task, with only minor variations. It almost seemed as though the author was trying to pad out the solution count to the magic number 100. A simple example: three solutions in chapter one cover (a) replacing smart quotes with straight quotes, (b) replacing copyright symbols with the (c) tri-graph, and (c) replacing trademark symbols with the (tm) sequence. In each case, the expression was simply "s/\xhh/ rep /g;". Did we really need three separate chapters for that? I don't think so.
Another quibble revolves around some of the coding of the expressions. Nathan has made liberal use of the non-capturing groups (that is, (: expr )) to insure only the items that needed replacement were captured. While a worthy idea, in some cases the expression may have been simplified for understanding. Another issue is a slight error in searching for letters. In a number of expressions, Nathan uses [A-z] to capture all letters. Unfortunately, the special characters [, \, ], ^, _, and ` occur between upper-case Z and lower-case a, making it match too much. Either [[:alpha:]] or [A-Za-z] should have been used.
Despite these quibbles, Regular Expression Recipes does provide a useful compendium of solutions for common problems developers face. Presenting the information in a cookbook fashion, along with ensuring that those using something other than Perl don't have to sweat translating the expressions to their target language, makes this a handy book to have. I wouldn't hesitate to recommend it.
You can purchase Regular Expression Recipes: A Problem-Solution Approach from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
I was performing a strange custom regular expression on the book review, and discovered that it outputted the following:
"Regex coders are in league with the devil"
Who woulda thunk it!
liqbase
...is the best regular recipe.
2. the index has a lot of typos.
No problem, the website issued a global regex and a pot of tip-ex for all customers.
liqbase
I'm not sure I understand what your quibble is - do you dislike the fact that he uses non-capturing groups, or the fact that he disposes of them at certain points?
Another issue is a slight error in searching for letters. In a number of expressions, Nathan uses [A-z] to capture all letters. Unfortunately, the special characters [, \, ], ^, _, and ` occur between upper-case Z and lower-case a, making it match too much. Either [[:alpha:]] or [A-Za-z] should have been used.
This seems like a relatively novice mistake, and I'm surprised it would show up in a book on regular expressions.
Despite these quibbles, Regular Expression Recipes does provide a useful compendium of solutions for common problems developers face. Presenting the information in a cookbook fashion, along with ensuring that those using something other than Perl don't have to sweat translating the expressions to their target language, makes this a handy book to have. I wouldn't hesitate to recommend it.
It's nice that he covers five environments for regular expressions. I'm sure everyone has heard of Mastering Regular Expressions, published by O'Reilly. The Perl Cookbook also does a good job at solving common problems with Regular expressions.
This is just my opinion, but I think what the world needs is a book on Regular Expression Design Patterns.
I can relate. I have cookbooks for food that have all these recipes that are nothing but flour, butter, eggs, and sugar. Do we need all these recipes for pancakes, cupcakes, cookies, crepes, waffles, popovers, bread, quick bread, bread sticks? Won't people figure out eventually to put a little less sugar in waffles with savory ingredients?
Japanese cookbooks are even worse. Soy sauce, sake, mirin...boooooooring!
Some people, when confronted with a problem, think ``I know, I'll use regular expressions.'' Now they have two problems.
Jamie Zawinski
I'm feeling a bit verklempt!
Talk amongst yourselves!
Alright, I'll give you a tawpic:
"Regular Expressions are neither regular nor expressions."
Discuss.
Anyone have any good recipies for [cookies]+ ?
> *11-page* regex.
I think that's a sure sign of insanity. Or autism at the least.
Yeah, mod me down as a troll, don't even READ my comment. [...]
You dumb slashbot fucks have no idea what a regex is [...]
Sycophants and asshats, monkeys who crawl around above my office trying to figure out which wire the rats chewed through. Know-nothing idiots [...]
Fuck you and your iPods. All those white earbuds do is help me pick out the clueless wannabes. No true geek would own one.
Let me guess... you didn't finish the Dale Carnegie course, did you?
"I'd rather be a lightning rod than a seismometer." -Ken Kesey
2. the index has a lot of typos.
Yeah, but in a book about regexes, you have to study the index VERY CAREFULLY to determine whether there are any typos or not.