Cryptic crossword puzzles (the ‘normal’ kind if you’re in the UK or a former Commonwealth country such as Canada) are defined by the style of cluing, nicely summarized by the Emily Cox & Henry Rathvon in the Wall Street Journal:

The clues each have two parts. One part is a normal definition of the answer; the other is an additional hint using wordplay. Having two hints in each clue might seem a big giveaway to solvers. Why aren’t these clues twice as easy? The hitch: Either hint may come first. The definition may appear before or after the wordplay hint, often without any punctuation to mark the point of division. The challenge and fun of a cryptic puzzle is to see through the puzzle writer’s deceptions, to tease out the definition by rethinking the clue’s wording.

Some people might describe a cryptic crossword as a puzzle where every clue is its own dad joke.

My cryptic crossword skills are…developing, but I not infrequently find myself stuck. In this old puzzle from Cox and Rathvon

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I was trying to solve 12A

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knowing only that it was a nine-letter word, the third letter being ‘O’ and the last being ‘U.

These constraints can be easily and compactly expressed as a simple regular expression

/^..O.....U$/

It had occurred to me in the past, that the ability to perform a regular expression search across a dictionary would be a useful tool to help solving this type of puzzle. While there are a number of sites available that offer this (Lou Helvy, dCode) and others, each suffers from shortcomings.

So I decided to create my own, tailored to my specific use case. The result provides an extremely simple user interface. The user enters a valid regular expression, and the tool continuously searches a large word list, displaying all matches, up to a preset limit:

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This is implemented in Python as a Gunicorn/Flask web service running on an inexpensive, low-powered Linux PC, reachable through a custom domain.

And if you’re wondering about that clue

Ceremonial dress is right in two ways for hearing

the words TRUE and SO are both synonyms for RIGHT, in the sense of correct. The two words spoken together (“TRUE-SO”) make a homophone of TROUSSEAU, a type of ceremonial dress.