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cl-change-case

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cl-change-caseutilstext

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This cool library is able to transform strings from one time of delimiters to others.

Previously I've used kebab, but cl-change-case is much more featureful:

POFTHEDAY> (cl-change-case:path-case "foo-bar-bazz")
"foo/bar/bazz"
POFTHEDAY> (cl-change-case:path-case "foo-bar_bazz")
"foo/bar/bazz"
POFTHEDAY> (cl-change-case:path-case "foo-bar-bazz")
"foo/bar/bazz"
POFTHEDAY> (cl-change-case:sentence-case "foo-bar-bazz")
"Foo bar bazz"
POFTHEDAY> (cl-change-case:snake-case "foo-bar-bazz")
"foo_bar_bazz"
POFTHEDAY> (cl-change-case:camel-case "foo-bar-bazz")
"fooBarBazz"
POFTHEDAY> (cl-change-case:no-case "foo-bar-bazz")
"foo bar bazz"
POFTHEDAY> (cl-change-case:header-case "foo-bar-bazz")
"Foo-Bar-Bazz"

When this can be useful? In cases when you interop with other systems, but want to use :this-style-of-symbols in Lisp. For example, you might generate identifiers for JavaScript or Python.

Another case is when you want to output labels for UI. Here I have a function which will render an HTML table describing a CLOS object:

POFTHEDAY> (defclass user ()
             ((created-at :initarg :created-at)
              (name :initarg :name)
              (num-posts :initarg :num-posts)))

POFTHEDAY> (defun render (object)
             (let* ((class-name (type-of object))
                    (class (find-class class-name))
                    (slots (closer-mop:class-slots class)))
               (cl-who:with-html-output-to-string (*standard-output* nil :indent t)
                 (:table
                  (loop for slot in slots
                        for slot-name = (closer-mop:slot-definition-name slot)
                        for label = (cl-change-case:sentence-case (symbol-name slot-name))
                        for value = (rutils:fmt "~A"
                                                (slot-value object slot-name))
                        do (cl-who:htm
                            (:tr
                             (:th (cl-who:esc label))
                             (:td (cl-who:esc value)))))))))

POFTHEDAY> (render (make-instance 'user
                                  :name "Bob"
                                  :created-at "2020-05-22"
                                  :num-posts 42))
"
<table>
<tr>
  <th>Created at</th>
  <td>2020-05-22</td>
</tr>
<tr>
  <th>Name</th>
  <td>Bob</td>
</tr>
<tr>
  <th>Num posts</th>
  <td>42</td>
</tr>
</table>"

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