Clarification of code comments in expr.c. Clean up the implementations

of sqlite3ExprIsVector() and sqlite3ExprVectorSize() slightly.

FossilOrigin-Name: 4fb66d6592b141a4a71359250dbd1ac454569cb9

manifest

@@ -1,5 +1,5 @@
-C Fixes\sfor\sproblems\sfollowing\sOOM\serrors.
+C Clarification\sof\scode\scomments\sin\sexpr.c.\s\sClean\sup\sthe\simplementations\nof\ssqlite3ExprIsVector()\sand\ssqlite3ExprVectorSize()\sslightly.
-D 2016-08-20T18:06:14.286
+D 2016-08-20T21:02:38.224
 F Makefile.in cfd8fb987cd7a6af046daa87daa146d5aad0e088
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc d66d0395c38571aab3804f8db0fa20707ae4609a
@@ -338,7 +338,7 @@ F src/ctime.c e77f3dc297b4b65c96da78b4ae4272fdfae863d7
 F src/date.c 95c9a8d00767e7221a8e9a31f4e913fc8029bf6b
 F src/dbstat.c 19ee7a4e89979d4df8e44cfac7a8f905ec89b77d
 F src/delete.c 76c084f0265f4a3cd1ecf17eee112a94f1ccbc05
-F src/expr.c e96f29a02a3927b2afaca1f86fc84e80cac50ca7
+F src/expr.c 4adf875e1bfc155b107ee8e35e7cb1c5599f955b
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c e2be0968c1adc679c87e467aa5b4f167588f38a8
 F src/func.c 29cc9acb170ec1387b9f63eb52cd85f8de96c771
@@ -1519,7 +1519,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8384c77ebb3f65fbc54c199885926f2066f0b140
+P 9041ee4a6f0e8389297f887f1431ab5cfe783390
-R d29ab3049f2812696918a926abccb285
+R bba779342591015bf7eda1fee0ab13af
 U drh
-Z 08f6ec095045e30304bec0161a676b54
+Z 030a18789c82832c6d203bdc6c28c7db

manifest.uuid

@@ -1 +1 @@
-9041ee4a6f0e8389297f887f1431ab5cfe783390
+4fb66d6592b141a4a71359250dbd1ac454569cb9

src/expr.c

@@ -313,9 +313,7 @@ static int codeCompare(
 ** Return true if expression pExpr is a vector, or false otherwise.
 */
 int sqlite3ExprIsVector(Expr *pExpr){
-  return ( (pExpr->op==TK_VECTOR)
+  return sqlite3ExprVectorSize(pExpr)>1;
-        || (pExpr->op==TK_SELECT && pExpr->x.pSelect->pEList->nExpr>1)
-  );
 }
 
 /*
@@ -325,28 +323,30 @@ int sqlite3ExprIsVector(Expr *pExpr){
 ** any other type of expression, return 1.
 */
 int sqlite3ExprVectorSize(Expr *pExpr){
-  if( sqlite3ExprIsVector(pExpr)==0 ) return 1;
+  if( pExpr->op==TK_VECTOR ){
-  if( pExpr->flags & EP_xIsSelect ){
+    return pExpr->x.pList->nExpr;
+  }else if( pExpr->op==TK_SELECT ){
     return pExpr->x.pSelect->pEList->nExpr;
+  }else{
+    return 1;
   }
-  return pExpr->x.pList->nExpr;
 }
 
 #ifndef SQLITE_OMIT_SUBQUERY
 /*
-** Interpret the pVector input as a vector expression.  If pVector is
-** an ordinary scalar expression, treat it as a vector of size 1.
-**
 ** Return a pointer to a subexpression of pVector that is the i-th
 ** column of the vector (numbered starting with 0).  The caller must
 ** ensure that i is within range.
 **
+** If pVector is really a scalar (and "scalar" here includes subqueries
+** that return a single column!) then return pVector unmodified.
+**
 ** pVector retains ownership of the returned subexpression.
 **
 ** If the vector is a (SELECT ...) then the expression returned is
-** just the expression for the i-th term of the result set, and is
+** just the expression for the i-th term of the result set, and may
-** necessarily ready to be evaluated because the table cursor might
+** not be ready for evaluation because the table cursor has not yet
-** not have been positioned yet.
+** been positioned.
 */
 Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
   assert( i<sqlite3ExprVectorSize(pVector) );
@@ -374,10 +374,10 @@ Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
 ** ensuring that the returned value eventually gets freed.
 **
 ** The caller retains ownership of pVector.  If pVector is a TK_SELECT,
-** then the return value will reference pVector and so pVector must remain
+** then the returne object will reference pVector and so pVector must remain
 ** valid for the life of the returned object.  If pVector is a TK_VECTOR
 ** or a scalar expression, then it can be deleted as soon as this routine
-** routines.
+** returns.
 **
 ** A trick to cause a TK_SELECT pVector to be deleted together with
 ** the returned Expr object is to attach the pVector to the pRight field