# Programming Clojure, Fourth Edition: Reference to regexp (page 26)

**URL:** <https://forum.devtalk.com/t/programming-clojure-fourth-edition-reference-to-regexp-page-26/233860>\
**Category:** PragProg Customers\
**Tags:** book-programming-clojure-fourth-edition, suggestion\
**Created:** [13 February 2026 00:16 UTC](https://forum.devtalk.com/t/programming-clojure-fourth-edition-reference-to-regexp-page-26/233860 "2026-02-13T00:16:38Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![grylix](https://forum.devtalk.com/user_avatar/forum.devtalk.com/grylix/32/7935_2.png) [@grylix](https://forum.devtalk.com/u/grylix)\
**Post date:** [13 February 2026 00:16 UTC](https://forum.devtalk.com/t/programming-clojure-fourth-edition-reference-to-regexp-page-26/233860/1 "2026-02-13T00:16:38Z")

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On page 26 you explain the use of anonymous functions with the example

```auto
(require '[clojure.string :as str])
(filter indexable-word? (str/split "A fine day it is" #"\W+"))
-> ("fine" "day")

```

You explain the invocation of `split` with “The call to split breaks the sentence into words, …”.  
Probably you could mention that with `#"\W+"` a regular expression is defined (which will probably be explained later in the book).

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<div class="post-metadata">

**Author:** ![alexmiller](https://forum.devtalk.com/user_avatar/forum.devtalk.com/alexmiller/32/1006_2.png) [@alexmiller](https://forum.devtalk.com/u/alexmiller)\
**Post date:** [13 February 2026 00:48 UTC](https://forum.devtalk.com/t/programming-clojure-fourth-edition-reference-to-regexp-page-26/233860/2 "2026-02-13T00:48:51Z")

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I’ve done a bit better and added a regular expressions subsection in the Reading Clojure section. Thanks!

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<div class="post-metadata">

**Author:** ![grylix](https://forum.devtalk.com/user_avatar/forum.devtalk.com/grylix/32/7935_2.png) [@grylix](https://forum.devtalk.com/u/grylix)\
**Post date:** [13 February 2026 09:18 UTC](https://forum.devtalk.com/t/programming-clojure-fourth-edition-reference-to-regexp-page-26/233860/3 "2026-02-13T09:18:57Z")

</div>

I have just seen that you use a regex on page 32 as well, and there you explain the reference.

> split splits the string around the regex matches (for whitespace),

Such a note could be used on page 26 as well. But a “regex” subsection is perfect, this section can be referenced from all usages.