[cryptonector]

Icon had (has!) "failure is falsity" / "value production is truth", and pervasive generators / backtracking. In Icon a function ("procedure") either: fails, returns a value, or suspends (yields) a value.

jq is very much like this too, as it has pervasive generators and backtracking, but unlike Icon jq does not distinguish between "returning" a value vs. "suspending" (yielding) a value.

The jq way kinda means you have to have booleans, and so jq does.

I'm suspicious of the no-booleans approach. After all, one could also have no integers (the Lambda Calculus doesn't have integers, having only function values!). Boolean values are just useful to have, and being able to obtain boolean values from predicates is useful too. One could do the Icon/Verse thing of failure is false / anything is true, but provide an adapter function that produces actual boolean values for when you need them.

[reacweb]

I was suspicious of javascript where number replaces int and double. The fail in verse is a way to replace boolean and null values. I think it is the direction of evolution.