How can I make an array of points created by a for loop in featurescript?

emory_krall

for (var i = 0; i < numberOfDowels; i += 1)
        {
            opPoint(context, id + ("locationPoint" ~ i), {
                        "point" : toWorld(cSys, vector((fenceDistance + (dowelSpacing * i)), 0 * inch, 0 * inch))
                    });
        }
        var locationPoints is array = evaluateQuery(context, qCreatedBy(id + ("locationPoint" ~ i), EntityType.BODY));

This gives me an error that the variable "i" is not found. If place the variable declaration within the for loop I can't reference it outside the loop, which is what I need to do.

NeilCooke

Another way (more id compliant) is:

var locationPoints = [];
for (var i = 0; i < numberOfDowels; i += 1)
{
    opPoint(context, id + ("locationPoint" ~ i), {&nbsp;
        "point" : toWorld(cSys, vector((fenceDistance + (dowelSpacing * i)), 0 * inch, 0 * inch))
    });
    locationPoints = append(locationPoints, qCreatedBy(id + ("locationPoint" ~ i), EntityType.BODY));
}
locationPoints = evaluateQuery(context, qUnion(locationPoints));

There are a few other ways besides.

Jake_Rosenfeld

I would do this like this:

const parentId = id + "points";
for (var i = 0; ...)
{
    opPoint(context, parentId + toString(i), {...});
}
const locationPoints = evauateQuery(context, qCreatedBy(parentId, EntityType.BODY));

Since ids are hierarchical, if you nest a bunch of child ids under a parent, you can just evaluate a query on the entire parent, and the query will be evaluated for the entire group of ids contained by the parent.

Note that:

id + ("points" ~ i)

creates ids that are like this "rootId > points0" "rootId > points1" "rootId > points2" (where the > is representing the transition of one id component to the next)

but:

(id + "points") + toString(i)
// which is equivalent to:
const parentId = id + "points";
parentId + toString(i)

creates ids that are like this "rootId > points > 0" "rootId > points > 1" "rootId > points > 2".  Then, because the ids are structured in a nice way, you can just do evaluations on parentId ("rootId > points"), and it will capture all of the ids which are children of that.

NeilCooke

i does not exist once outside the curly braces of the for loop. There are a number of ways you can do this, but it all depends on the rest of the script.

This is the most elegant way but may fall down if you have other similar loops in your code (due to id hierarchy):

for (var i = 0; i < numberOfDowels; i += 1)
{
    opPoint(context, id + i + "locationPoint", {                        
        "point" : toWorld(cSys, vector((fenceDistance + (dowelSpacing * i)), 0 * inch, 0 * inch))
    });
}

var locationPoints is array = evaluateQuery(context, qCreatedBy(id + ANY_ID + "locationPoint", EntityType.BODY));

NeilCooke

Another way (more id compliant) is:

var locationPoints = [];
for (var i = 0; i < numberOfDowels; i += 1)
{
    opPoint(context, id + ("locationPoint" ~ i), {&nbsp;
        "point" : toWorld(cSys, vector((fenceDistance + (dowelSpacing * i)), 0 * inch, 0 * inch))
    });
    locationPoints = append(locationPoints, qCreatedBy(id + ("locationPoint" ~ i), EntityType.BODY));
}
locationPoints = evaluateQuery(context, qUnion(locationPoints));

There are a few other ways besides.

emory_krall

Is "ANY_ID" meant to be used literally? When I try this I get the error "Typecheck canBeId failed"

NeilCooke

Yes, ANY_ID is a wildcard. Make sure it is spelled out exactly as above. I think you may be safer using the second method.

NeilCooke

Id hierarchy is a little difficult to follow: https://cad.onshape.com/FsDoc/library.html#Id

emory_krall

Thanks Neil, your second suggestion appears to work for me!

emory_krall

There is a typo in the code: "EntityType.Body" should be "EntityType.BODY"

NeilCooke

Yeah, sorry - I hand-typed it from memory. I've edited the post above for anybody else that might copy it.

Jake_Rosenfeld

I would do this like this:

const parentId = id + "points";
for (var i = 0; ...)
{
    opPoint(context, parentId + toString(i), {...});
}
const locationPoints = evauateQuery(context, qCreatedBy(parentId, EntityType.BODY));

Since ids are hierarchical, if you nest a bunch of child ids under a parent, you can just evaluate a query on the entire parent, and the query will be evaluated for the entire group of ids contained by the parent.

Note that:

id + ("points" ~ i)

creates ids that are like this "rootId > points0" "rootId > points1" "rootId > points2" (where the > is representing the transition of one id component to the next)

but:

(id + "points") + toString(i)
// which is equivalent to:
const parentId = id + "points";
parentId + toString(i)

creates ids that are like this "rootId > points > 0" "rootId > points > 1" "rootId > points > 2".  Then, because the ids are structured in a nice way, you can just do evaluations on parentId ("rootId > points"), and it will capture all of the ids which are children of that.