On 4/16/11 1:18 PM, "Bart Kiers" <bki...@gmail.com> wrote:
Hi All,
Just for archive I will show solution I was able built so far for our
Valentina SQL couple of LEXER rules.
The only not clear yet to me is:
if I must destroy temporary strings to avoid leaks?
Also I still wonder, if exists more compact and elegant and effective
solution
>From point of view of C developer? :-)
//--------------------------------------------------------------------------
----
// an identifier. Note that testLiterals is set to true! This means
// that after we match the rule, we look in the literals table to see
// if it's a literal or really an identifier
IDENT
: ( LETTER | '_' ) ( LETTER | '_' | DIGIT )*
;
DELIMITED // delimited_identifier
:
( DQUOTE ( ~(DQUOTE) | DQUOTE DQUOTE )+ DQUOTE
| BQUOTE ( ~(BQUOTE) | BQUOTE BQUOTE )+ BQUOTE
| LBRACK ( ~(']') )+ RBRACK // valentina extension [asasas '' "
sd "]
)
{
// Remove the first and the last chars:
pANTLR3_STRING pQuotedStr = GETTEXT();
pANTLR3_STRING pStr = pQuotedStr->subString( pQuotedStr, 1,
pQuotedStr->len - 1 );
SETTEXT( pStr );
}
{ $type = IDENT; }
;
And this is the second rule, more complex, because can be quotes inside:
//--------------------------------------------------------------------------
----
STRING_LITERAL
@init
{
int dquotes_count = 0;
}
: QUOTE
( ESCAPE_SEQUENCE
| ~('\'' | '\\')
| QUOTE QUOTE { ++dquotes_count; }
)*
QUOTE
{
// Remove the first and the last chars:
pANTLR3_STRING pQuotedStr = GETTEXT();
pANTLR3_STRING pStr = pQuotedStr->subString( pQuotedStr, 1,
pQuotedStr->len - 1 );
char* pStart = (char*) pStr->chars;
while( dquotes_count-- )
{
char* pFirstQuote = strchr( pStart, '\'' );
if( *(pFirstQuote + 1) != '\'' ) // second quote?
continue;
// Example: 'aabbcc''def'
int CharsOnLeft = pFirstQuote - pStart + 1;
int CharsToMove = pStr->len - CharsOnLeft;
ANTLR3_MEMMOVE( pFirstQuote + 1, pFirstQuote + 2,
CharsToMove );
// prepare for possible next loop:
pStart = pFirstQuote + 1;
pStr->len--;
}
SETTEXT( pStr );
}
;
--
Best regards,
Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc
Valentina - Joining Worlds of Information
http://www.paradigmasoft.com
[I feel the need: the need for speed]
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