How to access #1 inside conditional inside array->forEach

Question

I trying to learn captures in Lasso 9, but I am struggling to figure out how to access the #1 local variable from within a conditional that's inside an array->forEach capture. Maybe my approach is all wrong. Is there a reference to the parent capture that I need to use? Following is the working code:

define paramstovars() => {

    local(p = web_request->params)

    #p->foreach => {
        local(i = #1)
        if(#i->type == 'pair') => {
            var(#i->first->asstring = #i->second->asstring)
        }
    }

}

Following is the code I am trying to get working without relying on a redundant local variable definition:

define paramstovars() => {

    local(p = web_request->params)

    #p->foreach => {
        if(#1->type == 'pair') => {
            var(#1->first->asstring = #1->second->asstring)
        }
    }

}

In this second example, I receive an error that Position was out of range: 1 max is 0 (Error Code -1) on the line calling var().

Obvious security concerns with this custom method aside, what's the most efficient way to make #1 available inside nested conditionals?

Answer 1

#1 is replaced within each capture — so yes, you will need to assign it to another local in order to use it in deeper captures. If you need to work with the local again try using query expressions instead:

 with i in web_request->params do {
    if(#i->type == 'pair') => {
        var(#i->first->asstring = #i->second->asstring)
    }
}

Also, I wouldn't recommend settings variables in this fashion — it posses a security risk. It would be better to store the parameters in a single variable and then potentially set specific variables from that. There's a set of tags that does something similar here: getparam / postparam