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how to extract STRING content? [message #780819]

Thu, 19 January 2012 09:03

Mauro Condarelli
Messages: 365
Registered: September 2009

Senior Member

Hi,
the built-in terminal STRING, when used in grammar rules, returns the
literal string complete with escape sequence and bracketing quotes.

This is unsurprising.

I want to extract the supposed "value" of the string literal and I'm a
bit surprised I didn't find a standard way to do it.

If I understand correctly I should define a grammar rule like:

StringValue returns ecore::EString: value=STRING;

and then implement my own value converter.
Is this true?

I would be more than a bit surprised this very basic functionality isn't
included in the standard framework.

Am I missing something?

TiA
Mauro

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Re: how to extract STRING content? [message #780824 is a reply to message #780819]

Thu, 19 January 2012 09:17

Christian Dietrich
Messages: 4426
Registered: July 2009

Senior Member

Hi, you mix up parser rules that result in an class with Data type
rules that result in an edatatype. So the grammar you posted makes no
sense at all. Regards Christian

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Re: how to extract STRING content? [message #780843 is a reply to message #780824]

Thu, 19 January 2012 10:07

Mauro Condarelli
Messages: 365
Registered: September 2009

Senior Member

Il 19/01/2012 15:17, Christian Dietrich ha scritto:
> Hi, you mix up parser rules that result in an class with Data type rules
> that result in an edatatype. So the grammar you posted makes no sense at
> all. Regards Christian

Sorry, my bad.

Grammar should read:

terminal SCONST returns ecore::EString:
'"' ( '\\' ('b'|'t'|'n'|'f'|'r'|'u'|'"'|"'"|'\\') | !('\\'|'"') )* '"'
|
"'" ( '\\' ('b'|'t'|'n'|'f'|'r'|'u'|'"'|"'"|'\\') | !('\\'|"'") )* "'"
;

.... but question remains: How do I get the unescaped value of the
string, as opposed to the escaped and quoted value STRING returns?

Is the only method to define a custom converter?

TiA
Mauro

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Re: how to extract STRING content? [message #780846 is a reply to message #780843]

Thu, 19 January 2012 10:38

Christian Dietrich
Messages: 4426
Registered: July 2009

Senior Member

Yes you need a ValueConverter - XText doesnt know anything about your semantics (or reuse the one from STRING)

~Christian

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