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C'est la Z

Learning Elisp 17 - a thesaurus mode

When we last left our heroes we had made the API call to, gotten the response and coverted the json string into elisp data. Specifically an array that contained a hash table.

Today's video will take us the rest of the way to our thesaurus mode - run the function and we'll get a list of synonyms for the word we're currently at.

First, we had to pull out the synonyms from the response. To do that we used basic elisp data manipulation. We used (aref json-resp 0) to pull out the hash table, which was the 0th element of the array response, then wrap that in (gethash "meta"…) to pull out the "meta" hash entry. That's a hash table in its own right so we then pull out the "syns" element with another gethash and then finally, since that's an array with an array in it, another aref. The complete code is up at gitlab but it's essentially:

 (aref (gethash "syns" (gethash "meta"  (aref json-resp 0))) 0)

This gives us an array of synonym strings but we want it to be a list so we used mapcar to convert.

  (mapcar #'identity word-list)

There's probably a better way to do this but that's what came to mind.

From there, the actual function to replace the word under the cursor with its synonym is pretty straightforward:

(defun word-to-syn (n)
  (interactive "p")
  (let* ( (word (current-word))
          (word-list (get-synonyms word))
          (new-word (completing-read "Replacement:" word-list)))
    (kill-word 1)
    (insert new-word)))

The current-word function returns the word at or before the cursor location. We then use the get-synonyms function that we just completed and then use completing-read which lets us select a word from the synonym list.

Once we have the replacement word, it's just buffer manipulations to delete the old word and insert the new one.

The rest of the video shows turning this into a mode and binding the function to a key.

So, that's it for the elisp series for now. I'll do more if I can think of interesting and fun things to do but no promises.

You can get all the code at the repo linked below:


The code for the series is still up here:

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