All I want for Christmas

[Scott_Sauyet]

@CodaCoder

Let is a pass-thru operator, akin to @Yaisog’s debug operator both of which can be sprinkled throughout the expression without interrupting the logic in any way

Ah yes, of course. And then available inside the rest of the filter, right, not just outside as test1 would be. Makes sense.

@CodaCoder

It was in my mind as I wrote it out. Though I don’t recall anything about in-situ variable assignment in filters.

An example from that thread is

[my.custom.function<param>,[2]] =>index [<data>jsonget[top],<index>]

So it’s here more like a filter-run suffix, and not inline the way your suggestion is. Got it.

@CodaCoder

I’d argue that’s both valid/expected (in that context) but also a side-effect – whereas v...10 is direct and clear.

You’re absolutely right. I was missing a fundamental point on my first reading, that this is entirely pass-though. I’m liking it more and more!

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I’m still not sure I follow the advantage of having both the let[v] and the let[v...] syntaxes. How would you use the former in a way that the latter would not work just as well? I see (now! thank you) that let[v...10] would be different and necessary, but I’m still not seeing the rationale for the let[v] format.