Im making firefox extension. One function stores value in every tab, to use it later by other function.
function setValue(value) {
var attr = gBrowser.document.createAttribute("value");
attr.value = value;
gBrowser.document.attributes.setNamedItem(attr);
};
function getValue() {
var attr = gBrowser.document.attributes.getNamedItem("value");
if (attr != undefined && attr != null)
return attr.value;
else
return null;
};
For some reason, this doesn't work. Can you spot an error in my code?
Function getValue() should get value of active tab.
There are more errors than code here:
There's no gBrowser.document - you probably meant gBrowser.ownerDocument or just document (equivalent but simpler).
Neither is gBrowser.document.attributes, you meant gBrowser.attributes.
Using attributes seems very weird, an equivalent to the fixed up version of your code would be gBrowser.setAttribute("value", value) and gBrowser.getAttribute("value")
The fixed up code still isn't what you probably need and you didn't specify what exactly do you need (gBrowser.mCurrentTab.setAttribute?)
Related
I'm new to Dart and just learning the basics.
The Dart-Homepage shows following:
It turns out that Dart does indeed have a way to ask if an optional
parameter was provided when the method was called. Just use the
question mark parameter syntax.
Here is an example:
void alignDingleArm(num axis, [num rotations]) {
if (?rotations) {
// the parameter was really used
}
}
So I've wrote a simple testing script for learning:
import 'dart:html';
void main() {
String showLine(String string, {String printBefore : "Line: ", String printAfter}){
// check, if parameter was set manually:
if(?printBefore){
// check, if parameter was set to null
if(printBefore == null){
printBefore = "";
}
}
String line = printBefore + string + printAfter;
output.appendText(line);
output.appendHtml("<br />\n");
return line;
}
showLine("Hallo Welt!",printBefore: null);
}
The Dart-Editor already marks the questionmark as Error:
Multiple markers at this line
- Unexpected token '?'
- Conditions must have a static type of
'bool'
When running the script in Dartium, the JS-Console shows folloing Error:
Internal error: 'http://localhost:8081/main.dart': error: line 7 pos 8: unexpected token '?'
if(?printBefore){
^
I know, that it would be enough to check if printBefore is null, but I want to learn the language.
Does anyone know the reason for this problem?
How to check, if the parameter is set manually?
The feature existed at some point in Dart's development, but it was removed again because it caused more complication than it removed, without solving the problem that actually needed solving - forwarding of default parameters.
If you have a function foo([x = 42]) and you want a function to forward to it, bar([x]) => f(x);, then, since foo could actually tell if x is passed or not, you actually ended up writing bar([x]) => ?x ? foo(x) : foo();. That was worse than what you had to do without the ?: operator.
Ideas came up about having a bar([x]) => foo(?:x) or something which pased on x if it was present and not if it was absent (I no longer remember the actual proposed syntax), but that got complicated fast, fx converting named arguments to positional - bar({x,y}) => foo(?:x, ?:y); - what if y was provided and x was not. It was really just a bad solution for a self-inflicted problem.
So, the ?x feature was rolled back. All optional parameters have a default value which is passed if there is no matching argument in a call. If you want to forward an optional parameter, you need to know the default value of the function you are forwarding to.
For most function arguments, the declared default value is null, with an internal if (arg == null) arg = defaultValue; statement to fix it. That means that the null value can be forwarded directly without any confusion.
Some arguments have a non-null default value. It's mostly boolean arguments, but there are other cases too. I recommend using null for everything except named boolean parameters (because they are really meant to be named more than they are meant to be optional). At least unless there is a good reason not to - like ensuring that all subclasses will have the same default value for a method parameter (which may be a good reason, or not, and should be used judiciosuly).
If you have an optional parameter that can also accept null as a value ... consider whether it should really be optional, or if you just need a different function with one more argument. Or maybe you can introduce a different "missing argument" default value. Example:
abstract class C { foo([D something]); }
class _DMarker implements D { const _DMarker(); }
class _ActualC {
foo([D something = const _DMarker()]) {
if (something == const _DMarker()) {
// No argument passed, because user cannot create a _DMarker.
} else {
// Argument passed, may be null.
}
}
}
This is a big workaround, and hardly ever worth it. In general, just use null as default value, it's simpler.
I was trying something similar:
This does not work
widget.optionalStringParameter ? widget.optionalStringParameter : 'default string'
This works
widget.optionalStringParameter != null ? widget.optionalStringParameter : 'default string'
This also works
widget.optionalStringParameter ?? 'default string'
There was support for checking if an optional parameter was actually provider in early Dart days (pre 1.0) but was removed because it causes some troubles.
I know how to make the cache cleared for view :
.state('app.list', {
cache : false,
url: "/lists/:listId",
views: {
'menuContent': {
templateUrl: "templates/listDashboard.html",
controller: 'listDashboardCtrl'
}
}
})
, but I need something else - delete all the cache for the app in controller method. how to do it?
I found a solution, Wrap the clearCache and ClearHistory in a $timeout. Something Like this.
$scope.logout = function(){
$location.path('/signin')
$timeout(function () {
$ionicHistory.clearCache();
$ionicHistory.clearHistory();
$log.debug('clearing cache')
},300)
}
Edit:Changed Timeout seconds
You can use $ionicHistory. From documentation:
clearCache()
Removes all cached views within every ionNavView. This both removes the view element from the DOM, and destroy it's scope.
In your listDashboardCtrl write this:
function listDashboardCtrl($scope, $ionicHistory){
$ionicHistory.clearCache();
}
Well this is an old issue, but for anyone that's coming 2017 or later I will explain what really happens and how to solve it:
The code of $ionicHistory.clearCache():
clearCache: function(stateIds) { return $timeout(function() {
$ionicNavViewDelegate._instances.forEach(function(instance) {
instance.clearCache(stateIds); }); }); }
So, as you can see, it takes 1 parameter cllaed stateIds which is an array of stateId. Indeed i struggled to find out that stateId is nothing more than stateName.
So, let's go deeper. The code of $ionicNavView.clearCache which is used in the line above "instance.clearCache(stateIds)" is:
self.clearCache = function(stateIds) {
var viewElements = $element.children();
var viewElement, viewScope, x, l, y, eleIdentifier;
for (x = 0, l = viewElements.length; x < l; x++) {
viewElement = viewElements.eq(x);
if (stateIds) {
eleIdentifier = viewElement.data(DATA_ELE_IDENTIFIER);
for (y = 0; y < stateIds.length; y++) {
if (eleIdentifier === stateIds[y]) {
$ionicViewSwitcher.destroyViewEle(viewElement);
}
}
continue;
}
if (navViewAttr(viewElement) == VIEW_STATUS_CACHED) {
$ionicViewSwitcher.destroyViewEle(viewElement);
} else if (navViewAttr(viewElement) == VIEW_STATUS_ACTIVE) {
viewScope = viewElement.scope();
viewScope && viewScope.$broadcast('$ionicView.clearCache');
}
}
};
And as you can see in the code, this clearCache DOES NOT CLEAR ALL CACHES, instead, it destroy all cached views that matches a value in the stateIds array. If there's no parameter IT JUST DESTROY THE ACTUAL VIEW.
So the solution for this, using just the Ionic way is to call $ionicHistory.clearCache() with all your state names in an array as parameter.
E.g:
$ionicHistory.clearCache(['login', 'map', 'home']);
I cannot belive any Ionic developer didnt dug into the code before, or missed this simple datail.
I Hope someone takes advantage of this, even being so late.
UPDATE: Just to make it crystal clear, i want to point out where the bug itself is (if we can call it bug), maybe can be handy for devs:
self.clearCache = function(stateIds){
[...]
var viewElements = $element.children();
}
What the whole function does is basically:
Get all elements using JQLite
Loop the elements
Check if an element equals one in the StateIds array and destroy it; go to next element.
Check if element in the loop is cached or active, and in both true cases destroy it
I wont dig deeper into this but debugging it i could see that the elements gotten from var viewElements = $element.children(); is not an array of all your views content, not even the cached ones, intentionally or not it does not loop through out all your states to clear all those that matches 'ACTIVE' or 'CACHED'. If you want it to loop through ALL your states and destroy all cached views and data you need to explicity pass the stateIds array parameter.
Besides there's another strange behavior, because when i was debugging it i saw when the var viewElements array was filled up with 2 elements, and these 2 elements were from the same state, one resolved to 'CACHED' another resolver to 'ACTIVE', even resolving to the 2 types used in the if conditions the cache was not cleared at all.
I personally think that this is somekind wrong implemented or is wide used wrongly. The fact is that there's a lot of people cracking their heads on this and devs don't even give this simple explanation.
I'm trying to update my code but I'm stuck at this codeline.
How do I proceed to convert this to preg_replace_callback?
$buffer = preg_replace("#§([a-z0-9-_]+)\.?([a-z0-9-_]+)?#ie","\$templ->\\1(\\2)",$buffer);
Here is the process of converting preg_replace (with the e modifier) to preg_replace_callback. You create a function that will act on all of the matches that it finds. Normally this is pretty simple, however with your case it is a little more complex as the function returns the value of an object. To accommodate this, you can use an anonymous function (a function without a name) and attach the USE keyword with your object to it. This can be done inline, however for the sake of clarity, I have made it its own variable.
Take a look at this portion of the complete code below:
$callback_function = function($m) use ($templ) {
I created a variable named callback_function that will be used in the preg_replace_callback function. This function will be fed each match as the variable $m automatically. So within the function you can use $m[1] and $m[2] to access the parts of the expression that it matched. Also note that I've attached the $templ variable with the USE keyword so that $templ will be available within the function.
Hopefully that makes sense. Anyway, here is the complete code:
<?php
// SET THE TEXT OF THE BUFFER STRING
$buffer = 'There are a bunch of §guns.roses growing along the side of the §guns.road.';
// THIS IS JUST A SAMPLE CLASS SINCE I DO NOT KNOW WHAT YOUR CLASS REALLY LOOKS LIKE
class Test {
// FUNCTION NAMED 'guns' WITH A SPACE FOR A PARAMETER
public function guns($info) {
return '<b>BLUE '.strtoupper($info).'</b>';
}
}
// INSTANTIATE A NEW 'Test' CLASS
$templ = new Test();
// THIS IS THE FUNCTION THAT YOUR CALLBACK WILL USE
// NOTICE THAT IT IS AN ANONYMOUS FUNCTION (THERE IS NO FUNCTION NAME)
$callback_function = function($m) use ($templ) {
return $templ->$m[1]($m[2]);
};
// THIS USES PREG_REPLACE_CALLBACK TO SUBSTITUTE OUT THE MATCHED TEXT WITH THE CALLBACK FUNCTION
$buffer = preg_replace_callback('/§([a-z0-9-_]+)\.?([a-z0-9-_]+)?/i', $callback_function, $buffer);
// PRINT OUT THE FINAL VERSION OF THE STRING
print $buffer;
This outputs the following:
There are a bunch of <b>BLUE ROSES</b> growing along the side of the <b>BLUE ROAD</b>.
I am working with the selections within the Eclipse source code editor. I defined a key-binding that gets me the "text" at the current caret position. I managed to parse the current caret position to an IJavaElement
private void processEditorSelection(IEditorPart part, ITextSelection selection) {
IEditorInput editorInput = ((IEditorPart) part).getEditorInput();
final ITypeRoot root = (ITypeRoot) JavaUI.getEditorInputJavaElement(editorInput);
if (root != null) {
int offset = (selection).getOffset();
IJavaElement[] codeSelect = root.codeSelect(offset, 0);
if (codeSelect.length > 0) {
//codeSelect[0...n] are my resolved elements at the current caret pos.
}
What I did not managed to figure out yet is, how to resolve the enclosing type. for instance:
public void do() {
System.out.println("it");
}
If the caret is on the System.out, I obtain an JavaElement of the system out call, but I am actually interested in the enclosing method. Does anyone know how to ask Eclipse for the enclosing type? Like what is the compilation unit or method my current carret position is enclosed in?
Thanks for an answer
You are looking to do something like this:
ITypeRoot root = (ITypeRoot) JavaUI.getEditorInputJavaElement(editorInput);
IJavaElement elt = root.getElementAt(caretPosition);
This will find the enclosing element, which may be an IField, IMethod, or ICompilationUnit. To get the enclosing type, call this:
IType type = (IType) elt.getAncestor(IJavaElement.TYPE);
This method returns null if there is no enclosing type.
I'm trying to intercept events using Gdk.Window.AddFilter(Gdk.FilterFunc) in Mono. So far, I have been able to hook up the filter function, but now I am trying to use the events in the filter function.
This is what I have in the filter function so far:
private Gdk.FilterReturn FilterFunction(IntPtr xEvent, Gdk.Event evnt)
{
if (evnt.Type == Gdk.EventType.KeyPress)
{
Gdk.EventKey eventKey = (Gdk.EventKey)evnt; // fails here
if (eventKey.Key == this.key && eventKey.State == this.modifiers)
{
this.OnPressed(EventArgs.Empty);
}
}
return Gdk.FilterReturn.Continue;
}
How can I convert the Gdk.Event to Gdk.EventKey? I have tried casting it, but that doesn't seem to work.
Edit: Oops! The problem was that I had accidentally added a semicolon to the if statement, making it an empty statement. For some reason, the Gdk.Event does not correspond to the XEvent, so I am now pursuing a solution that uses the XEvent instead.
Why don't you try printing out the type so you can see what it really is? (it may not be EventKey)
Like:
Console.WriteLine (evnt.GetType ());
(or pause it in a debugger and examine it to see the type)