How to programmatically add custom functions?

Question

I'm trying to build a rather unique google sheets addon. Google's documentation is great for adding custom functions, however I want my addon to programmatically add custom functions.

For instance, the following doesn't seem to be possible:

• Assume there's a getScript() custom function where if you do getScript("scraper"), this custom function will do an HTTP call and install a new function scraper() in your google sheet.
• Then you can do scraper("https://www.google.com") to get all the text from "google.com".

I know it's possible to define scraper() ahead of time.

Is it possible to do so live?

Answer 1

The Google Apps Script platform have changed a lot since this question was posted back in 2014. Regarding editor add-ons they can't add random custom functions but they could send parameters to an external API that might include a function name and the required parameters by that function by using UrlFetchApp.