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Validating x,y coordinates [message #1787047]

Thu, 17 May 2018 17:48

Jack Lee

Messages: 3
Registered: May 2018

Junior Member

Hello, I am working on an assignment and have a slight issue understanding something about validation and the grammar.

Currently this is my grammar (only showing relevant parts, ... is omitted code):

Game:
    'Game' name=ID grid=GridSize ...
;

GridSize:
   'Grid' 'size' size=Coordinates
;

Coordinates:
'('x=INT','y=INT')'
;
...

And this is my validation definition:

@Check
    def void checkGridCoordinates(Game game) {
    	val minValue = 1
    	val maxValue = 10
    	var x = game.grid.size.x
    	var y = game.grid.size.y
    	var literal = MetaGameLanguagePackage.Literals.GRID_SIZE__SIZE
    	
    	if(x < minValue || y < minValue){
    		error("Grid size must be at least 1.",literal)	
    	} else if(x > maxValue || y > maxValue) {
    		this.error("Grid size must be 10 or under.", literal)
    	}
    }

I get the following error, which happens if I try to set the grid x and y to be either 0 or under or above 10 (which is expected but I want it to display the error message and not fail to validate):

Description	Resource	Path	Location	Type
Error executing EValidator	TestingFile.gl	/IndividualExtension/src	/IndividualExtension/src/TestingFile.gl	GameLang Problem

Since this is an assignment I would appreciate it if you could hint me in a direction in which I can experiment, instead of handing me a solution :)

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Re: Validating x,y coordinates [message #1787090 is a reply to message #1787047]

Fri, 18 May 2018 16:30

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

first of all you should write a unit test for your validator
the classes parsehelper and validationtesthelper will help

@RunWith(XtextRunner)
@InjectWith(MyDslInjectorProvider)
class MyDslParsingTest {
	@Inject
	ParseHelper<Game> parseHelper
	
	@Inject
	extension ValidationTestHelper
	
	@Test
	def void loadModel() {
		val result = parseHelper.parse('''
			Game HelloWorld Grid size (1,11)
		''')
		Assert.assertNotNull(result)
		val errors = result.eResource.errors
		Assert.assertTrue('''Unexpected errors: «errors.join(", ")»''', errors.isEmpty)
		result.assertNoErrors // Triggers validation
	}
}

this will give you an actual stack trace (you would find it in the eclipse runtime error log too)
the stacktrace should hint you to your problem

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Validating x,y coordinates [message #1787114 is a reply to message #1787090]

Sat, 19 May 2018 04:05

Jack Lee

Messages: 3
Registered: May 2018

Junior Member

Thank you very much! Turns out the issue was I was in the wrong context and thus the feature was not being exposed. However as you can see in my below code I had to use eINSTANCE and not

MetaGameLanguagePackage.Literals.GRID_SIZE__SIZE

. I have yet to understand why Literals didn't do the job.

@Check
def void checkGridCoordinates(GridSize grid) {
    	// Variables
    	var minValue = 1
    	var maxValue = 10
    	var x = grid.size.x
    	var y = grid.size.y
    	var gridSize = MetaGameLanguagePackage.eINSTANCE.gridSize_Size
    	
    	if(x < minValue || y < minValue){
    		error("Grid size must be at least 1.", gridSize)	
    	} else if(x > maxValue || y > maxValue) {
			error("Grid size must be 10 or under.", gridSize)
    	}
    }

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