Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

v.k.

Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

in Processing with Other Languages • 2 months ago

If you open examples after selecting javaScript from modes menu, different examples show up. One of them is a cool example on how to use javaScript to build and use HTML form's elements as inputs for a sketch. I could not find this online so I pasted it here:

https://gist.github.com/anonymous/6042811

Anyway in that example there is this lines of code (isolated by me):

 
             
              String[] menuItems;
               
               void setup ()
               {
                   menuItems = new String[] {
                         new String[] {"Rectangle"}, new String[] {"Ellipse"},
                       new String[] {"Star"}, new String[] {"Spirograph"}
                   };
               }

Well I don't know this kind of initialisation for an array, and if I run this code in Java mode it gives me a

"cannot convert from String[] to String"

So appears that the compiler doesn't know it also... What is this?

When I tried to remove all the new Strings[] the menu created only shows the first letter of each string...

I'm founding very difficult to work in javaScript mode,

as there is no messages from complier and debugging is much harder, and now this...

I don't even know which secction to put this question in

thanks for any help.

Replies(6)

PhiLho

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

That's an array of arrays, so you need a double array syntax:

              
               String[][] menuItems;
              
 The init can be simplified too, if moved to the declaration site:
              
               String[][] menuItems = {
                        {"Rectangle"}, {"Ellipse"},
                        {"Star"}, {"Spirograph"}
                    };

Makio135

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

Indeed this code is weird...

"cannot convert from String[] to String"

menuItems is defined as a String[] (an Array of String) but in its initialization:

menuItems = new String[] {
new String[] {"Rectangle"}, new String[] {"Ellipse"},
new String[] {"Star"}, new String[] {"Spirograph"}
};

the code tries to put several String[] ( String Array ) with one String in it... meaning menuItems should be a String[][] (Array of String Array)

To create menuItems as a String[], the correct way should be:

menuItems = new String[] {
"Rectangle", "Ellipse", "Star", "Spirograph"
}
};

By checking the example code, i found that the problem is due to this line in interface.js:

option.innerHTML = o[i][0];

it should be:

option.innerHTML = o[i];

So you need to correct this line + the way menuItems is created (menuItems = {"Rectangle", "Ellipse", ...})

The code was working in JSMode 'cause javascript is not as much a typed language as Java and thus way more flexible.

Makio135
http://makio135.com/

GoToLoop

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

Initializing an Array by filling them up w/ items inside curly brackets is 1 of the many "tricks" Java's creators did to convince C/C++ folks to try Java out!

When still trying to work my way in learning Processing, I was startled to find out that "trick" doesn't work
while re-assigning another Array instance to an already-declared variable!

It took me a while to figure out that the syntax becomes a little more complicated
and doesn't match C's anymore!

While declaring w/ curly braces, there's no need to specify both keyword new and its type!
We can if we wish though!

But once we need to reassign it again, they are required!

String[][] menuItems = {
         {"Rectangle"}, {"Ellipse"},
         {"Star"}, {"Spirograph"}
     };
     
println(menuItems[0]);
println();

/*  Doesn't work!
menuItems = {
      {"Quadrants", "Circular"},
      {"Comets", "Interplanetary"}
  };
}

println(menuItems[0]);
*/

menuItems = new String[][] {
      {"Quadrants", "Circular"},
      {"Comets", "Interplanetary"}
  };

println(menuItems[0]);

exit();

v.k.

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

PhiLho, I know about arrays of arrays of someType, but the example is indeed mixing them up, and javaScript seams to fail silently... Or worse it worked anyway... Probably the author have tried the GoToLoop's way, but with a little more new String[][] than needed.

GoToLoop, thanks this little detail is novelty for me, glad to learn :)

Makio, that did it. I also changed:

var value = o[i].length > 1 ? o[i][1] : i;

var value = o[i].length > 1 ? o[i] : i;

two lines above the line you pointed, that is right, isn't it?

also initialization of the array becomes:

menuItems = new String[] {"Rectangle","Ellipse","Star","Spirograph"};

And every thing is working fine now, even the new menu that I was adding with an array of ints as menuItems. I think that's ok as js doesn't mind if I pass an array of ints or strings, right?

so now i have:

String muneItems[];
int anosExistente = (year()-1945)+1;
int[] menuAnos;
void setup ()
{
menuItems = new String[] {
"Projeto de Lei - PL","Medida Provisória - MDV",
"Projeto de Decret Lei Esquisito - PDE","Projeto de Decreto Lei - PDC"};
menuAnos = new int[anosExistente];
for (int i = 0; i < menuAnos.length; i++){
menuAnos[i] =1945+i;
}

and later

void setController ( Controller ctlr )
{
// labels are supposed to be existing function names
element = ctlr.addMenu( "setSigla", menuItems );
ctlr.setElementLabel( element, " Tipo de Proposição: " );
element = ctlr.addMenu( "setAno", menuAnos );
ctlr.setElementLabel( element, " Ano: " );
}

all working fine.

As a last thought, should it be reported some how, so they can fix the example?

There is another thing that I think is incorrect in the example, but is a CSS stuff, so... I don't know.

In the:

/**
* <form id="form-form"></form>
*
* <style>textarea,input,label,select{display:block;width:95%}select{width:97.5%}
* input[type=checkbox],input[type=radio]{width: auto}textarea{height:5em}</style>
*/

isn't

textarea,input,label,select{display:block;width:95%}

and

select{width:97.5%}

redundant?

Thanks you all.

Makio135

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

Okay, i read all this interface.js and found out why it was using a [][] instead of a simple []:

menuItems should be a String[][] (instead of "String[] menuItems", my mistake sorry) and that was the only error in the code.

Initializing menuItems is presented this way:

menuItems = new String[][] {
new String[] {"Rectangle"},
new String[] {"Ellipse"},
new String[] {"Star"},
new String[] {"Spirograph"}
};

This way, you create Items in your menu just by giving their name.

But you can add a second String in the Item which is an int, like that:

menuItems = new String[][] {
new String[] {"Rectangle", "3"},
new String[] {"Ellipse", "1"},
new String[] {"Star", "2"},
new String[] {"Spirograph", "0"}
};

This way you specify the value you want to associate to the Item.

In the example, the value of the Item is applied to currentShape.

And if you don't specify the Item's value, it takes the position of the Item in menuItem.

You can report the menuItems[] / [][] error on github here: https://github.com/fjenett/javascript-mode-processing/issues

Concerning the CSS, it is a current practice:

textarea,input,label,select{display:block;width:95%}
select{width:97.5%}

it could be replaced by:

textarea,input,label{display:block; width:95%}
select{display:block; width:97.5%}

But this way, the "display:block;" would be the redundant part.

Makio135
http://makio135.com/

v.k.

Re: Illegal Java needed for javaScript? Can some one explain me this part of variableInput example?

2 months ago

Ah, now I see. Thanks for that. It's a clever js script isn't it? I'm kind of learning some javaScript with yours answers. :)

Do you know a good place online to start understanding javaScript?

Meanwhile what is the meaning of:

label['for'] = id;

and

label.id = id+'-label';

Thanks makio :)

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