Re: How to declare a multidimensional array?

[Sven Efftinge]

It's not supported out-of-the box. You can add support by declaring a Java class like this :

public class ArrayLiterals2 {

@Inline("new int[$1][$2]")

public static int[][] intArray(int outerSize, int innerSize) {

throw new UnsupportedOperationException();

}

}

and import it like this in Xtend :

import static extension my.lib.ArrayLiterals2.*

…

  val int[][] arr = intArray(10,20)

 

@Inline tells the compiler to replace any calls to the annotated method with the to-be-inlined Java expression (the 'value' template).

Note that the @Inlined is not stable API (flagged as @Beta) and will likely be removed once Xtend has support for more powerful method-macros.

On May 1, 2013, at 2:39 PM, funk...@gmail.com wrote:

What's Xtend's syntax equivalent for Java's multi-dimensional array syntax:
e.g.
Type[][] matrixData = new Type[Dim1][Dim2];?

NewArrayOfSize() is only set up for single dimensions.

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[vangel...@gmail.com]

Hi,

Thanks, for the beginners' sake, could you please also give the syntax how to get and set arr[x][y]?

Cheers,
Attila

[Sven Efftinge]

Hi Attila,

use ‘get' as in :

val int[][] arr = #[#[1,2], #[3,4]]

assertEquals(3, arr.get(1).get(0))

Sven

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[vangel...@gmail.com]

Hi Sven,

Thanks for the quick reply. Then

arr[x][y] = n;

in Java would become:

arr.get(x).set(y, n)

in xtend. This may be slightly confusing (especially for others, who did not write the code).
Furthermore

arr[x][y]++;

in Java would become something like:

arr.get(x).set(y, arr.get(x).get(y) + 1)

This is much worse to read. What is the solution for this?
I imagine it would be possible to write some static setter or increaser functions (e.g. with @Inline), but it still does not feel right.

Regards,
Attila

[Stefan Oehme]

You are right, this is inconvenient and we are looking for ways to improve this. The workaround depends on what you are trying to do. If it's just a few places, you could write some extension methods like array.increment(i, j). If you have a single class that is very array-heavy, you could just write that one class in Java.

[ramanapa...@gmail.com]

What is alternate way to store and retrieve values in multidimensional array in Xtend ? 

[Christian Dietrich]

Hi, what is your exact problem with defining own array extensions?

[Ramana Pandiri]

I'm unable to initialize multi dimensional array in xtend class.

I want to add some csv file elements to multi dimensional array and then I want to validate. 

Thanks & Regards, 

RAMANA. 

On Thu 29 Nov, 2018, 5:00 PM Christian Dietrich, <christian.di...@gmail.com> wrote:

Hi, what is your exact problem with defining own array extensions?

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[Christian Dietrich]

Xtext and Xtend 2.16 (due next week)

will add a

@Pure
    @Inline("new $4[$1][$2]")
    public static <T> T[][] newArrayOfSize(int size0, int size1) {
        throw new UnsupportedOperationException(
                "This method relies on the inlined compilation (see @Inline annotation), and cannot be used from Java or with an uncustomized interpreter."); //$NON-NLS-1$
    }

you can add something like that yourself if you need higher dimensions or have it in older versions