Eclipse Community Forums: TMF (Xtext)

Help

Home

Home » Modeling » TMF (Xtext) » grammar

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

grammar [message #1070748]

Thu, 18 July 2013 15:31

Yueming Hong

Messages: 87
Registered: April 2013

Member

HI,
Has anyone try to define a grammar rule which could accept any characters?
I am trying, but cannot do it myself:
I want define a single rule for all content, and each line of content would be one element. Then use the framework provided by xtext to do the content assist, coloring, validation and so on...

However, I have no idea to define such a rule:
('a'..'z'|'A'..'Z'|'#'|'!') (.)+ ('\r\n'|'\n')

this could do a similar job, but each line is not recognized in this rule until seeing ('\r\n'|'\n'). so the content assist cannot be applied.

BTW, how can I not to use the default terminal rules? removing "with org.eclipse.xtext.common.Terminals" will lead to the disability of defining new terminal rule.

Many Thanks

sincerely,
YM

Report message to a moderator

Re: grammar [message #1070845 is a reply to message #1070748]

Thu, 18 July 2013 20:20

Yueming Hong

Messages: 87
Registered: April 2013

Member

Does anyone know how to provide content assist for non-recognized content?
if i use this:
('a'..'z'|'A'..'Z'|'#'|'!') (.)+ ('\r\n'|'\n')

it won't be recognized as an element until ('\r\n'|'\n')

but i want to provide content assist before that~

thanks

Report message to a moderator

Re: grammar [message #1070847 is a reply to message #1070845]

Thu, 18 July 2013 20:22

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi

for custom datatype rules and terminals you simply have to override the corresponding method in the proposal provider

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

Report message to a moderator

Re: grammar [message #1070849 is a reply to message #1070845]

Thu, 18 July 2013 20:24

Yueming Hong

Messages: 87
Registered: April 2013

Member

it would be quite limited if I can only provide content assist for recognized element~

Report message to a moderator

Re: grammar [message #1070853 is a reply to message #1070847]

Thu, 18 July 2013 20:26

Yueming Hong

Messages: 87
Registered: April 2013

Member

But code like this:
if(line.input.startsWith('#')){
val proposal = 'include'
acceptor.accept(createCompletionProposal(proposal, context))
}
does not do the job.

am i wrong ?

Report message to a moderator

Re: grammar [message #1070855 is a reply to message #1070847]

Thu, 18 July 2013 20:32

Yueming Hong

Messages: 87
Registered: April 2013

Member

hi Chris,
This is my grammar,
LCFGModel:
(elements+=Line)*
;

Line :
input = INPUT
;

terminal INPUT:
START (.)* END
;
terminal END:
'\r\n'|'\n'
;

terminal START:
'!'|'#'|'a'..'z'| 'A'..'Z'
;

Actually i want it to accept any character in each line and process each line with my customized code.

Do you have any other feasible way to do this?

Report message to a moderator

Re: grammar [message #1070859 is a reply to message #1070855]

Thu, 18 July 2013 20:45

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi,

the proposalprovider is the (only) hook.

btw

class MyDslProposalProvider extends AbstractMyDslProposalProvider {
	
	override complete_INPUT(EObject model, RuleCall ruleCall, ContentAssistContext context, ICompletionProposalAcceptor acceptor) {
		super.complete_INPUT(model, ruleCall, context, acceptor)
		if (context.prefix.startsWith("#")) {
			acceptor.accept(createCompletionProposal("#include",context))
		}
	}
	
}

works for me

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

Report message to a moderator

Re: grammar [message #1070868 is a reply to message #1070859]

Thu, 18 July 2013 21:13

Yueming Hong

Messages: 87
Registered: April 2013

Member

Great Thanks.

But i have some puzzles:
the complete{TypeName}_{FeatureName} applies to feature of type, and complete_{RuleName} applies to rule. Why does complete_INPUT work instead of completeLine_Input?

what does "context" mean here? anything i have typed in so far?

thank you

Report message to a moderator

Re: grammar [message #1070886 is a reply to message #1070868]

Thu, 18 July 2013 22:04

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hi there a multiple methods that apply
The Context gives you Information about where you are
I gutes in your Case the Problem was that your proposal did Not include the #

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

Report message to a moderator

Re: grammar [message #1070895 is a reply to message #1070886]

Thu, 18 July 2013 22:44

Yueming Hong

Messages: 87
Registered: April 2013

Member

No, proposal "#include" does not work either.

I thought the reason why mine doesn't work is : the rule is not recognized until "\r\n" is typed, then the complete method can be applied.
However, since yours works, i guess this is not the reason.

Nevertheless, THANKS~! Very Happy