[sqlite] How this /*A-overwrites-S*/ should work ?
Thanks for the answer ! > Wed Feb 24 2016 6:38:46 pm CET CET from "Richard Hipp" > > > The /*A-overwrites-S*/ comment is processed by Lemon, and Lemon has no > knowledge of #ifdefs. > > > I can understand that but it will confuse other people like it did to me ! Cheers !
[sqlite] How this /*A-overwrites-S*/ should work ?
I solved it setting a variable before " /*A-overwrites-S*/", but I's still
confusing it's usage inside a wrapped "#ifdef" that supposed only will be
executed conditionally.
Cheers !
oneselect(A) ::= SELECT|XSELECT(S) distinct(D) selcollist(W) from(X)
where_opt(Y)
groupby_opt(P) having_opt(Q) orderby_opt(Z)
limit_opt(L). {
? int isXSelect = @S == TK_XSELECT;
#if SELECTTRACE_ENABLED
? Token s = S; /*A-overwrites-S*/
#endif
? A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
? if(isXSelect) A->selFlags |= SF_NOFlattening;
#if SELECTTRACE_ENABLED
? /* Populate the Select.zSelName[] string that is used to help with
? ** query planner debugging, to differentiate between multiple Select
? ** objects in a complex query.
? **
? ** If the SELECT keyword is immediately followed by a C-style comment
? ** then extract the first few alphanumeric characters from within that
? ** comment to be the zSelName value.? Otherwise, the label is #N where
? ** is an integer that is incremented with each SELECT statement seen.
? */
? if( A!=0 ){
??? const char *z = s.z+ (isXSelect ? 7 : 6);
??? int i;
??? sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d",
++pParse->nSelect);
??? while( z[0]==' ' ) z++;
??? if( z[0]=='/' && z[1]=='*' ){
? z += 2;
? while( z[0]==' ' ) z++;
? for(i=0; sqlite3Isalnum(z[i]); i++){}
? sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "%.*s", i, z);
??? }
? }
#endif /* SELECTRACE_ENABLED */
}
[sqlite] How this /*A-overwrites-S*/ should work ?
Here is the full changes I did in parser.y:
?
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT|XSELECT(S) distinct(D) selcollist(W) from(X)
where_opt(Y)
groupby_opt(P) having_opt(Q) orderby_opt(Z)
limit_opt(L). {
#if SELECTTRACE_ENABLED
? Token s = S; /*A-overwrites-S*/
#endif
? A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
? if(@S == TK_XSELECT) A->selFlags |= SF_NOFlattening;
#if SELECTTRACE_ENABLED
? /* Populate the Select.zSelName[] string that is used to help with
? ** query planner debugging, to differentiate between multiple Select
? ** objects in a complex query.
? **
? ** If the SELECT keyword is immediately followed by a C-style comment
? ** then extract the first few alphanumeric characters from within that
? ** comment to be the zSelName value.? Otherwise, the label is #N where
? ** is an integer that is incremented with each SELECT statement seen.
? */
? if( A!=0 ){
??? const char *z = s.z+ (@S == TK_XSELECT ? 7 : 6);
??? int i;
??? sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d",
++pParse->nSelect);
??? while( z[0]==' ' ) z++;
??? if( z[0]=='/' && z[1]=='*' ){
? z += 2;
? while( z[0]==' ' ) z++;
? for(i=0; sqlite3Isalnum(z[i]); i++){}
? sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "%.*s", i, z);
??? }
? }
#endif /* SELECTRACE_ENABLED */
}
?
[sqlite] How this /*A-overwrites-S*/ should work ?
Hello !
I have a modification on the parser.y for my own purposes and it was been
parsed till the introduction of " /*A-overwrites-S*/" and it seems that
something is wrong on parser.y see bellow, after the SELECT specification the
" /*A-overwrites-S*/" is wrapped by "#if SELECTTRACE_ENABLED" that is not
enabled in my build but the " /*A-overwrites-S*/" still seem to be active,
even if I move the " /*A-overwrites-S*/" after the usage of " if(@S ==
TK_XSELECT)" I still get the same error.
parse.y:495: Label S used after '/*A-overwrites-S*/'.
How to get this to be parsed again ?
Cheers !
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).? {A = @OP; /*A-overwrites-OP*/}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT|XSELECT(S) distinct(D) selcollist(W) from(X)
where_opt(Y)
groupby_opt(P) having_opt(Q) orderby_opt(Z)
limit_opt(L). {
#if SELECTTRACE_ENABLED? ///<<< this seems to intend to disable
/*A-overwrites-S*/ but it doesn't !
? Token s = S; /*A-overwrites-S*/
#endif
? A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
? if(@S == TK_XSELECT) A->selFlags |= SF_NOFlattening;
#if SELECTTRACE_ENABLED
[sqlite] How this /*A-overwrites-S*/ should work ?
On 2/24/16, Domingo Alvarez Duarte wrote: > I solved it setting a variable before " /*A-overwrites-S*/", but I's still > confusing it's usage inside a wrapped "#ifdef" that supposed only will be > executed conditionally. The /*A-overwrites-S*/ comment is processed by Lemon, and Lemon has no knowledge of #ifdefs. -- D. Richard Hipp drh at sqlite.org
[sqlite] How this /*A-overwrites-S*/ should work ?
On 2/24/16, Domingo Alvarez Duarte wrote: > Hello ! > > I have a modification on the parser.y for my own purposes and it was been > parsed till the introduction of " /*A-overwrites-S*/" and it seems that > something is wrong on parser.y see bellow,\ The /*A-overwrites-S*/ comment is a hint to the parser generator that it can optimize by avoiding copy of a stack element in the PDA. You may safely remove the comment. -- D. Richard Hipp drh at sqlite.org
