list_contains() never returns false; asserts instead

[wjcarpenter]

It looks like it's trying to return false, but it doesn't.

causes_assert = list_contains(["aaa", "bbb"], "ccc");

[ERROR: Assertion '((index >= 0) && (index < len(list)))' failed: "List does not contain value 'ccc'index is invalid len '2' index '2' List:["aaa", "bbb"]" in file modules/functions_gridfinity.scad, line 146](https://github.com/ostat/gridfinity_extended_openscad/issues/146,/home/wjc/.../gridfinity_extended_openscad/modules/functions_gridfinity.scad)
[TRACE: called by 'list_contains' in file modules/functions_gridfinity.scad, line 149](https://github.com/ostat/gridfinity_extended_openscad/issues/149,/home/wjc/.../gridfinity_extended_openscad/modules/functions_gridfinity.scad)

[ostat]

Does causes_assert get used anywhere?

To call a function you need to have variable = function(). If you just call the function() openscad assumes it's a module.

It might be a strange way to work around the language.

[wjcarpenter]

I don't quite understand your comment. My one-liner is just a simple example. The function returns a boolean, and for the case where the second argument is found in the list, it does return true.

[ostat]

Oh, I get you, sorry I was thinking of something else.

you are right it should be this (I think).

echo(first=list_contains(["aaa", "bbb", "ccc"], "aaa"));
echo(last=list_contains(["aaa", "bbb", "ccc"], "ccc"));
echo(missing=list_contains(["aaa", "bbb", "ccc"], "ddd"));
echo(only=list_contains(["aaa"], "aaa"));


/* Data types */
function list_contains(list,value,index=0) = 
  assert(is_list(list), "list must be a list")
  assert(index >= 0 && index < len(list), str("List does not contain value '", value, "'index is invalid len '" , len(list) , "' index '", index, "' List:", list))
  list[index] == value 
    ? true 
    : index < len(list)-1  ? list_contains(list,value,index+1)
    : false;