TomFrost
commented
3 years ago Hi Colin!
At the end of the day it all boils down to personal preference, as there's no functional advantage to one over the other. The readme suggests transforms for two main reasons:
- Jexl was written for its expressions to be understood and written by savvy non-programmers. If you're not already used to the
function(arg)syntax employed by C-like languages, then the subject-verb left-to-right flow ofprice|roundUpcan feel more natural thanroundUp(price). I pulled that syntax from the family of popular template languages based on Django's (Twig, Nunjucks, etc) where those expressions were also optimized for folks who aren't traditionally programmers. - With the introduction of functions that overlap the functionality of transforms, I felt it was good form to provide a guideline for the community so that Jexl code could be shared without having to be concerned with a codebase's internal conventions. So the options there were 1. Recommend using functions and deprecate transforms because they no longer have a use, or 2. Recommend using transforms for their original purpose and reap the ease-of-use benefits of my first point above. So I decided on 2.
So there you have it! If the function syntax makes more sense to you and anyone you have that might be writing these expressions, by all means you should use that :). If the above reasons could be impactful for you, though, transforms still have a nice place within the language definition.
Enjoy!
cmdcolin
Great work on this library. I was wondering about your perspective on functions vs transforms
The readme suggests: "While Transforms are the preferred way to change one value into another value, Jexl also allows top-level expression functions to be defined"
And I see that functions are actually a recent addition, so this is pretty cool, but do you have any reasons why transforms would be preferred?