Introducing Signals – The Next Big Thing in Application Management

Sky-Tiger

will
bind op to the first parameter
ignore the second parameter as idiomatically expressed with the _ wild card
and using the & separator will isolate all the remaining elements in a sequenced referred by the cdr expression
The :as keyword allows for the aliasing of the complete input collection using the expression parameter name.

My intent , aliasing the whole input expression, was to provide meat to a pre condition checking (yes like in design by contract). Pre-condition checking are a bless specifically when they stop you before your blindness fires a stack overflow .
Back to the make-sum function variable arity, one can see that I delegate all the work to the version accepting sequences as parameters. I could have not used destructuring into the second signature. I found it an idiomatic way to express that the function was specifically expecting a sequence.

As the tests showed earlier, I had to take into account various scenarii like the identity element for the sum, that can lead to a single element expression, the fact that all the list operands are pure numbers etc...

Filtering identity elements induces a recursion step after the filter step. We should memoize some ...state (?) in order to not indefinitely filter zeros from the input expression.But state is bad, we all know it. Decorating the filtered list with a meta information can be a smooth way to proceed. Once the immutable filtered sequence created, we do not alter its content or use a third method signature. We attach to the data a meta information:

Sky-Tiger

I am working on a Github account, so next time I will give you a link I hope

We have been using destructuring, meta data, and function variable arity, all Clojure's idiomatic forms, in one small program, not so unrealistic (shoot me if you never had to write a small interpreter in your real coder's life. If not, you have been lucky)