RegexBuddy : Java Glossary

Introduction

RegexBuddy helps you compose, understand, convert, test and debug regexes. The current version is 4.8.2 Last revised/verified: 2018-02-19.

It costs . for updates.

How it Works

It shows your regex co lour coded:

It also shows the meaning of your regex in English.

Disadvantages

• RegexBuddy has seven windows, all of which can disappear, or move, all of which are unlabeled. You just supposed to know what goes in what. You can look at the videos and watch what the author does with each window, but your windows don’t look a bit like his and it not at all clear what you could do to make yours look like his. Perhaps he could give them different pastel colour backgrounds with a key.
• It highlights errors, but it does not consider a nugatory \ an error or warning or flaggable.
• It shows you how far it got in trying to match a test string.
• Unfortunately, the two windows are not linked as well as I would like. If you click on a part of the regex is will scroll the corresponding part of the explanation into view with faint highlight, but does not necessarily show you any context before and after. When you click on the explanation, the colours in the regex change, but not in a way you can figure out which character corresponds.
• Unfortunately for me, it does not handle Funduc Search/Replace or SlickEdit regexes though one of the ones it does support might be similar to SlickEdit. Funduc is eccentric with prefix notation and capture without parentheses.
• When you are composing it does not display the characters that have to be quoted. You have to guess, then look at the colour coding to see if you guessed correctly by reading below if the character was interpreted literally. It has a feature called insert-token that lets you click a button to insert a literal character and it figures out if it needs to be quoted. However, this is cumbersome compared with directly keying in literal mode. If you quoted something that did not need it, it will not tell you. This drives me nuts even though it has no practical consequences. My problem is I use three different systems within a day and I get them muddled.
• Buying from the website is quite confusing. There are dozen of plausible ways to use it that do not work. Key a 1 in the box next to RegexBuddy and click the PayPal icon after scrolling down to the very bottom of the page. Then wait for an email and carefully follow the instructions. You don’t just paste your registration number into the evaluation copy, as is traditional.

Advantages

• When I put regexes I thought were correct into RegexBuddy, I discovered all kinds of subtle problems. The problem with regexes is you don’t get error messages from Java when they are a bit off. Oddly, the stilted English description of what my regex does is the most useful feature in figuring out why a regex is not working. You discover, for example, that an inadvertently doubled \ is looking for a literal \ or that an unescaped . is looking for any character.
• It handles a about 30 different languages (Java, C, C#, Delphi, Groovy, Perl, PHP (Pre-Hypertext Processor), Postgres, Python, PowerShell, R, Ruby, SQL (Standard Query Language),Td, XML (extensible Markup Language) ) and regex schemes.
• It has helpful and strict modes.
• It comes with dozens of canned snippets for matching common patterns, e.g. credit cards, number ranges, URLs… It is almost impossible to write your own URL (Uniform Resource Locator) regex from scratch that handles all the variants. Here you just paste it in, it will work first time and will not leave out some obscure character that rarely appears in URLs (Uniform Resource Locators).
• The test feature lets you type in a sample string to match It shows you how far it got matching.
• You can also provide a set of strings that should match and a set that should not match. Most regex errors involve accepting a string it should not. People tend to test only with valid strings.
• It has a GUI (Graphic User Interface) regex grep built in.
• If you are at all familiar with regexes, all is pretty straight forward. However, I still have not figured out how to use DEBUG. I have spent less than an hour exploring it and have not yet read the manual.

• One of my problems is remembering which characters need to be quoted when you mean them literally. I use three different regex schemes is a day. Each has a different set of dangerous characters for searching and replacing regexes. RegexBuddy offers the following help for Java Regexes:

  If you can’t remember which characters you need to escape, simply switch to the Create panel, click the Insert Token button, select the Literal Text item and enter the text you want to add as a literal to your regular expressions. RegexBuddy then automatically escapes all characters that need to be escaped following the rules for the application that you have selected. This is helpful for newly created regexes but does not help me check that I have no excess quoting in existing regexes.

• It has a clever colour-coding scheme that uses background colours to help you proofread.

  RegexBuddy Colour Legend

  RegexBuddy Colour Legend
  Background Colour	Meaning
  white	literal text
  light blue	white space
  green	parentheses. Deeper nesting uses darker colours to help you pair them up by eye. also |.
  orange	[…] individual characters.
  dark orange	[…] character ranges and classes.
  grey	quoted chars. Unnecessarily quoted char look the same. I am trying to talk the author into changing that.

• It tells you in computerese English just what your regex does. Many times when I read this exposition, I discovered an error that was not obvious when I read the regex itself. The problem when I read the regex is I see what I want the regex to do, not what it actually does.
• The author Jan Goyvaerts responds quickly to emails.

Tips

• If your test panel disappears, you can bring it back with Alt-5. Click the view icon to bring back any of the other panels.
• To debug a regex, under view, select side-by-side mode. Make sure you have line-by-line mode on. Make sure you have case-sensitive/case-insensitive set. Put your test lines in the Window under the Test button. Click debug everywhere. Click highlight to see what it is collecting for each group.
• Click in the upper right, then click regex colours, then configure selected text to something distinctive like magenta. Then it will be much easier to figure out which part of your regex corresponds to which part of the explanatory text. This panel will also show you all the colours and what they mean.

RFEs (Request For Enhancements)

• Unnecessarily quoted characters should be displayed in a variant colour. The author has rejected this RFE (Request For Enhancement) despite vigorous needling.
• Java programmers think in terms of finding, matching and lookingAt. There terms appear nowhere. Instead you have terms like debug here. This is confusing. The problem may be that RegexBuddy is not strictly for Java.
• It tells you about it successes and failures in terms of column number. Sometimes it also shows you with highlights, but not always. It should always show highlights.