On Sep 3, 2015 4:17 AM, "Domingo Alvarez Duarte" <sqlite-mail at dev.dadbiz.es>
wrote:
>
> Hello !
>
> I was looking at this particular commit
> https://www.sqlite.org/src/info/0ea6e5c9fc6b1dd1 then I realize the usage
of
> magic number through sqlite3 source code like the one bellow, it's not
good
> practice to avoid then ?
Generally yes, but like most decisions made in programming, there are
exceptions. Much like goto: avoid it when nothing better is available, but
use it when it is the right tool.
Besides, I have seen code that is harder to read when certain magic numbers
are replaced by named constants. It isn't common, but it happens.
>
> Cheers !
>
> ===== case PragTyp_STATS: { static const char *azCol[] = { "table",
> "index", "width", "height" }; Index *pIdx; HashElem *i; v =
> sqlite3GetVdbe(pParse); pParse->nMem = 4; ///////first appearance
of
> the a magic number (sizeof(azCol)/sizeof(char*))
> sqlite3CodeVerifySchema(pParse, iDb); setAllColumnNames(v, 4, azCol);
> //////// second appearance of a magic number described above
> for(i=sqliteHashFirst(&pDb->pSchema->tblHash); i; i=sqliteHashNext(i)){
> Table *pTab = sqliteHashData(i); sqlite3VdbeAddOp4(v, OP_String8,
0,
> 1, 0, pTab->zName, 0); sqlite3VdbeAddOp2(v, OP_Null, 0, 2);
> sqlite3VdbeAddOp2(v, OP_Integer,
> (int)sqlite3LogEstToInt(pTab->szTabRow), 3); sqlite3VdbeAddOp2(v,
> OP_Integer,
>
> =====
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