Eclipse Community Forums: TMF (Xtext) » alternate between assignment and terminal

Help

Home

Home » Modeling » TMF (Xtext) » alternate between assignment and terminal

Show: Today's Messages :: Show Polls :: Message Navigator

alternate between assignment and terminal [message #948796]

Thu, 18 October 2012 11:36

Dominik Hirt

Messages: 2
Registered: October 2012

Junior Member

I want to define as part of a grammar, the possibility to define the length of a given parameter with these xtext parser rule:

Length:
    ((min=INT)? ('..')? max=INT) | '#' 
;

Such a rule is syntactically correct and makes the following terms possible:

1..5
..4
3
#

I want to express, that for the case '#' the length isn't defined and set min=max=-1. How can I achieve that ? This is not only important for the unit test which can't check min and max values because they are not defined:

val de = model.segments.head.datenElemente.head as DE
assertEquals("0", de.length.min) <-- NullPointerException

How can I mix the assignments of min and max and this special case with terminal '#' ?

Kind Regards
Dominik

Report message to a moderator

Re: alternate between assignment and terminal [message #948895 is a reply to message #948796]

Thu, 18 October 2012 13:49

Michael Ernst

Messages: 49
Registered: July 2010

Member

It should be easy to define the value in the EMF model as default value. Go to the Eclipse properties view and define a default value!

Report message to a moderator

Re: alternate between assignment and terminal [message #949218 is a reply to message #948895]

Thu, 18 October 2012 20:20

Dominik Hirt

Messages: 2
Registered: October 2012

Junior Member

If I select that part of my grammar in my xtext file and open the properties view ... there isn't any possibility to set a default value ... ?

Report message to a moderator

Re: alternate between assignment and terminal [message #949251 is a reply to message #949218]

Thu, 18 October 2012 21:06

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

for the default value you have to:
- use a postprocessor to change the metamodel (http://christiandietrich.wordpress.com/2011/07/22/customizing-xtext-metamodel-inference-using-xtend2/)
- use a manually maintained metamodel

for the NPE you have to take care of the warnings Xtext gives you

Length:
   ((min=INT)? ('..')? max=INT) |{Length}  '#' 
;

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

Report message to a moderator

Previous Topic:	Exchange the InputStream
Next Topic:	Generating enums with methods (and fields)

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Thu Apr 25 19:43:41 GMT 2024

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter