| Cross References & Strings [message #639454] |
Tue, 16 November 2010 11:11  |
Eclipse User |
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Hi to all!
I need to devoloped a parser and I come across with xtext a couped weeks ago.
I love it but I have some doubts that I like to been explained.
1.) If I have something like this:
Prefix:
'prefix' name=(STRING|ID);
Command:
prefix=[Prefix] ':' arg=ID;
Why I only get the cross reference if the "prefix" is ID?
And how can I resolve it to get with cross reference with a string but unquoted?
2.) If my parser needs to allow something like this:
The following strings are equivalent:
hello
"hello"
'hello'
"hel" + "lo"
'hel' + "lo"
How can I differentiate a STRING from a ID?
3.) In relation to the second question, to concatenate strings with a plus sign ('+') I add the rule:
CUSTOMSTRING:
(STRING ('+' STRING)*);
With this new rule did I really need to add a Value converter? For which prupose?
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| Re: Cross References & Strings [message #639869 is a reply to message #639454] |
Thu, 18 November 2010 03:40  |
| Eclipse User |
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1) Try
StringOrId:
STRING | ID;
Prefix:
'prefix' name=StringOrID;
Command:
prefix=[Prefix|StringOrID] ...
By default, cross references are expected to have the Syntax of an ID.
So prefix=[Prefix] is the same as prefix=[Prefix|ID]. If you don't want
that, you have to put the rule for the Syntax after a | in the square
brackets, as sketched above.
2) You don't have to, just use the delegating datatype rule as described
above.
3) If you don't provide a value converter, the plus sign will be part of
the String.
Am 16.11.10 17:11, schrieb PTavares:
> Hi to all!
> I need to devoloped a parser and I come across with xtext a couped weeks
> ago.
> I love it but I have some doubts that I like to been explained.
>
> 1.) If I have something like this:
>
> Prefix:
> 'prefix' name=(STRING|ID);
>
> Command:
> prefix=[Prefix] ':' arg=ID;
>
> Why I only get the cross reference if the "prefix" is ID? And how can I
> resolve it to get with cross reference with a string but unquoted?
>
>
> 2.) If my parser needs to allow something like this:
> The following strings are equivalent:
>
> hello
> "hello"
> 'hello'
> "hel" + "lo"
> 'hel' + "lo"
>
> How can I differentiate a STRING from a ID?
>
> 3.) In relation to the second question, to concatenate strings with a
> plus sign ('+') I add the rule:
>
> CUSTOMSTRING:
> (STRING ('+' STRING)*);
>
> With this new rule did I really need to add a Value converter? For which
> prupose?
--
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