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Lasso 9 Conditional for Existence in Nested Maps & Arrays

I frequently run into a situation where I am testing for the existence of a value in a nested map or array. To prevent verbose conditionals, I would like to simplify the code to not test for existence at each level of the node, instead going right after what I want.

For example:

local(mymap = map('a' = (:1,2,3), 'b' = (:4,5,6)))

if (#mymap->find('c')->contains(9) ) => {}

If key 'c' does not exist in #mymap, then the contains() method throws an error.

Would it be foolish of me to define this in Lasso Startup?

define void->contains(...) => false

That would allow the above conditional to work, without having to add compound expressions to first test if 'c' exists. Am I missing some unintended consequences? Am I overlooking a more efficient way to do this?

Solution

  • The way I go about it is to use an "or":

    if((#mymap->find('c') || (:)) >> 9) => {}

    What happens here is that if #mymap->find('c') produces a non-false value, it's used for the contains, otherwise the empty staticarray is use for the contains.