Details
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Task
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Resolution: Unresolved
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P2: Important
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None
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None
Description
Currently, it's rather cumbersome to tell the QML compiler that a local value in a function will always have the same type. You need to as-cast whenever you assign null or something that cannot be statically proven to be of the required type. Type assertions on locals would come in handy here.
Case in point:
property Variable prev
property Variable first
property Variable last
function chainTest(n: int) {
planner = newPlanner.createObject(null) as Planner;
prev = null;
first = null;
last = null;
// Build chain of n equality constraints
for (var i = 0; i <= n; i++) {
var name = "v" + i;
var v = newVariable.createObject(null, {name: name}) as Variable;
if (prev != null)
newEqualityConstraint.createObject(null, {v1: prev, v2: v, strength: Strength.REQUIRED});
if (i == 0) first = v;
if (i == n) last = v;
prev = v;
}
newStayConstraint.createObject(null, {myOutput: last, strength: Strength.STRONG_DEFAULT});
var edit = newEditConstraint.createObject(null, {myOutput: first, strength: Strength.PREFERRED}) as EditConstraint;
var edits = newOrderedCollection.createObject(null) as OrderedCollection;
edits.add(edit);
var plan = planner.extractPlanFromConstraints(edits);
for (var i = 0; i < 100; i++) {
first.value = i;
plan.execute();
if (last.value != i) // TODO: Bogus compile error!
console.error("Chain test failed.");
}
}
Here, I've factored out the locals into the surrounding object, and it still doesn't help as much as I would hope.