Eclipse Community Forums: TMF (Xtext) » Where do I define new grammar?

Help

Home

Home » Modeling » TMF (Xtext) » Where do I define new grammar?

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

Where do I define new grammar? [message #638566]

Thu, 11 November 2010 16:10

Chris Ainsley

Messages: 78
Registered: March 2010
Location: UK

Member

Hi,

Assuming I have just a single .xtext file (derived from one of the tutorial DSLs), how and where do I declare new terminators for my language.

If I declare terminators in another xtext file (adapted from the standard terminators), it is not reachable from my original xtext file. How does xtext resolve grammars.

I read in the user guide that I can declare other grammars but can someone give me a quick guide if I should declare the grammar in the same xtext file, in a separate xtext file, and if in a separate file - how do I make this grammar 'visible'?

Thanks,

Chris

Report message to a moderator

Re: Where do I define new grammar? [message #638579 is a reply to message #638566]

Thu, 11 November 2010 16:48

Meinte Boersma

Messages: 434
Registered: July 2009
Location: Leiden, Netherlands

Senior Member

Either I don't understand your question or(non-exclusive) you don't understand what Xtext is about, I guess. It's perfectly possible to define an entire grammar in one .xtext file: the referencing is primarily there for modularization of the grammar, but it doesn't have effect on the language defined by the grammar.

What do you mean with "terminators"? Maybe you mean terminals, but for the most part you don't have to bother with defining these in Xtext: the keywords and the in-built terminals cover >90% of all situations.

Xtext blogs: executable models...again? | workshop material | custom scoping with Xtend

Report message to a moderator

Re: Where do I define new grammar? [message #638587 is a reply to message #638579]

Thu, 11 November 2010 17:10

Chris Ainsley

Messages: 78
Registered: March 2010
Location: UK

Member

Meinte Boersma wrote on Fri, 12 November 2010 01:48

Hi,

I think I do mean 'terminals' and still learning xtext although I'm making a lot of progress today.

I think I may need to define new terminals because of the following language format

* Description of something to do = id : drivername

I wish to capture all the text between the asterisk and the '=' sign.

My grammar is currently defined as:

Item:
    '*' description=STRING '=' id=ID ':' driver=STRING ';';

However, this requires quotes around the string. If I define a new terminal then the mwe2 file does not compile correctly (my mistake obviously).

Can you suggest the best way I might be able to capture all the text between two tokens?

Thanks,

Chris

Report message to a moderator

Re: Where do I define new grammar? [message #638866 is a reply to message #638587]

Fri, 12 November 2010 20:00

Alexander Nittka

Messages: 1193
Registered: July 2009

Senior Member

Hi,

try something like

Item: '*' description=Description '=' id=ID ':' driver=STRING ';';

Description hidden(): (ID|WS)+;

Description is a datatype rule. It is better to use those (if possible) rather than defining new terminals as there may be unintended side effects (in particular if you don't really know what you are doing). You may have to implement a value converter in order to deal with leading and trailing white spaces.

Alex

Report message to a moderator

Re: Where do I define new grammar? [message #639363 is a reply to message #638566]

Tue, 16 November 2010 09:14

Jan Koehnlein

Messages: 760
Registered: July 2009
Location: Hamburg

Senior Member

Am 11.11.10 17:10, schrieb Chris Ainsley:
> Hi,
>
> Assuming I have just a single .xtext file (derived from one of the
> tutorial DSLs), how and where do I declare new terminators for my language.
>
> If I declare terminators in another xtext file (adapted from the
> standard terminators), it is not reachable from my original xtext file.
> How does xtext resolve grammars.

Xtext searches grammars along the classpath. Make sure your grammars
reside in source folders and the Java dependencies are set up correctly.

>
> I read in the user guide that I can declare other grammars but can
> someone give me a quick guide if I should declare the grammar in the
> same xtext file, in a separate xtext file, and if in a separate file -
> how do I make this grammar 'visible'?
>
> Thanks,
>
> Chris

--
Need professional support for Eclipse Modeling?
Go visit: http://xtext.itemis.com

---
Get professional support from the Xtext committers at www.typefox.io

Report message to a moderator

Previous Topic:	Problems in UI tests
Next Topic:	ResourceDescriptions in Validator

Goto Forum:

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

]

Current Time: Thu Apr 25 14:17:51 GMT 2024

.:: Contact :: Home ::.

Breadcrumbs

Sign up to our Newsletter