[antlr-interest] lexer: embedded quotes assistance

[向秦贤]

IMHO we can use two style without others.
QString: (DQ (~DQ)* DQ) |  (SQ (~SQ)* SQ);
DQ:'"';
SQ:'\'';
it works fine.
we can do this
"abc'sdfsa"
'abc"123"
or newline included
"ab
c'sdfsa"
'ab
c"123"

2007/8/24, Gavin Lambert <antlr at mirality.co.nz>:
>
> At 07:39 24/08/2007, Edwards, Waverly wrote:
> >Well after a lot more reading it is still not
> easy.  Below is what
> >I've done to capture the quoted text.  I'm hoping someone can
> >assist me.  My grammar is very short as at this
> point I just need
> >to get past capturing quotations with embedded
> quotes.  Below that
> >is the code I used to test what I was doing was correct ( or
> >seemingly correct ).  The code below the
> grammar works just fine.
> >I decided that instead of making an exception to allow the
> >continuation across lines I would throw an
> error if there was not
> >one, thereby saving myself more headaches.
>
> Not tested, but this ought to do what you want:
>
> DBLQUOTE
>    :  '"'
>       (~'"' | '""')*
>       '"'
>    ;
>
> (This will also permit line breaks inside
> strings.  If you want to disallow that then just
> change the ~'"' into ~('"' | NEWLINE).)
>
> This will match the entire string properly
> (detecting embedded double-quotes vs. the string
> terminator), but won't strip the surrounding
> quotes nor remove one of each quote pair.  I'm
> not a Javaite, so I can't give you exact code,
> but something along these lines ought to do that:
>
>    String original = $getText();
>    String text = original.substring(1, original.length() - 2);
>    text = text.replace("\"\"", "\"");
>    $setText(text);
>
> To do your line continuation you just need to add
> an extra alt into the main rule:
>    ... | '¬' NEWLINE ...
> And then add additional 'replace' calls in the
> action code to replace "¬\r\n" or "¬\n" with "".
>
>


-- 
致敬
向秦贤
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