Save about 800 bytes of code space by aligning TK_ and OP_ constants so that

we do not have to translate between them. (CVS 1998)

FossilOrigin-Name: 4c817e3f293a9c1365e632f7dc13ae440263332a

9 files changed, 193 insertions, 144 deletions

diff --git a/Makefile.in b/Makefile.in
index 75e8b0205..acb93b99e 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -286,18 +286,16 @@ pager.lo:	$(TOP)/src/pager.c $(HDR) $(TOP)/src/pager.h
 opcodes.lo:	opcodes.c
 	$(LTCOMPILE) -c opcodes.c
 
-opcodes.c:	$(TOP)/src/vdbe.c
+opcodes.c:	opcodes.h
 	echo '/* Automatically generated file.  Do not edit */' >opcodes.c
 	echo 'char *sqlite3OpcodeNames[] = { "???", ' >>opcodes.c
-	grep '^case OP_' $(TOP)/src/vdbe.c | \
-	  sed -e 's/^.*OP_/  "/' -e 's/:.*$$/", /' >>opcodes.c
+	grep OP_ opcodes.h | sort -n +2 | \
+	  sed -e 's/^.*OP_/  "/' -e 's/ [ 0-9]*$$/", /' >>opcodes.c
 	echo '};' >>opcodes.c
 
-opcodes.h:	$(TOP)/src/vdbe.h
+opcodes.h:	parse.h $(TOP)/src/vdbe.c $(TOP)/mkopcodeh.awk
 	echo '/* Automatically generated file.  Do not edit */' >opcodes.h
-	grep '^case OP_' $(TOP)/src/vdbe.c | \
-	  sed -e 's/://' | \
-	  awk '{printf "#define %-30s %3d\n", $$2, ++cnt}' >>opcodes.h
+	cat parse.h $(TOP)/src/vdbe.c | awk -f $(TOP)/mkopcodeh.awk >>opcodes.h
 
 os_mac.lo:	$(TOP)/src/os_mac.c $(HDR)
 	$(LTCOMPILE) $(THREADSAFE) -c $(TOP)/src/os_mac.c
diff --git a/main.mk b/main.mk
index 6912637b4..533fc2228 100644
--- a/main.mk
+++ b/main.mk
@@ -255,18 +255,16 @@ pager.o:	$(TOP)/src/pager.c $(HDR) $(TOP)/src/pager.h
 opcodes.o:	opcodes.c
 	$(TCCX) -c opcodes.c
 
-opcodes.c:	$(TOP)/src/vdbe.c
+opcodes.c:	opcodes.h
 	echo '/* Automatically generated file.  Do not edit */' >opcodes.c
 	echo 'char *sqlite3OpcodeNames[] = { "???", ' >>opcodes.c
-	grep '^case OP_' $(TOP)/src/vdbe.c | \
-	  sed -e 's/^.*OP_/  "/' -e 's/:.*$$/", /' >>opcodes.c
+	grep OP_ opcodes.h | sort -n +2 | \
+	  sed -e 's/^.*OP_/  "/' -e 's/ [ 0-9]*$$/", /' >>opcodes.c
 	echo '};' >>opcodes.c
 
-opcodes.h:	$(TOP)/src/vdbe.h
+opcodes.h:	parse.h $(TOP)/src/vdbe.c $(TOP)/mkopcodeh.awk
 	echo '/* Automatically generated file.  Do not edit */' >opcodes.h
-	grep '^case OP_' $(TOP)/src/vdbe.c | \
-	  sed -e 's/://' | \
-	  awk '{printf "#define %-30s %3d\n", $$2, ++cnt}' >>opcodes.h
+	cat parse.h $(TOP)/src/vdbe.c | awk -f $(TOP)/mkopcodeh.awk >>opcodes.h
 
 os_mac.o:	$(TOP)/src/os_mac.c $(HDR)
 	$(TCCX) -c $(TOP)/src/os_mac.c
diff --git a/manifest b/manifest
index 4d683c9e4..df40a7a6c 100644
--- a/manifest
+++ b/manifest
@@ -1,6 +1,6 @@
-C Fixes\sto\sthe\sOsUnlock()\sinterface.\s\sCorrectly\sleave\sa\sSHARED\slock\sbehind\nwhen\srequested.\s\sHonor\sthe\serror\scode\sthat\sOsUnlock()\sreturns.\nTicket\s#913\sand\s#938.\s(CVS\s1997)
-D 2004-10-02T20:38:28
-F Makefile.in abdeb5bd9d017822691884935c320037c33f6ee6
+C Save\sabout\s800\sbytes\sof\scode\sspace\sby\saligning\sTK_\sand\sOP_\sconstants\sso\sthat\nwe\sdo\snot\shave\sto\stranslate\sbetween\sthem.\s(CVS\s1998)
+D 2004-10-04T13:19:24
+F Makefile.in 78ddc9fca09ab6e3b75a79ecf8d490e34cd0519c
 F Makefile.linux-gcc a9e5a0d309fa7c38e7c14d3ecf7690879d3a5457
 F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
 F VERSION 0aeddfe96f008f6cbe2c7167a782f3133e118d8d
@@ -17,8 +17,9 @@ F doc/lemon.html f0f682f50210928c07e562621c3b7e8ab912a538
 F doc/report1.txt a031aaf37b185e4fa540223cb516d3bccec7eeac
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895
 F ltmain.sh f6b283068efa69f06eb8aa1fe4bddfdbdeb35826
-F main.mk fbe4b06ed4d32c529f1514595defe73a424a357e
+F main.mk cabfd4a3e786840e8924689b04751a8c48dc4a42
 F mkdll.sh 468d4f41d3ea98221371df4825cfbffbaac4d7e4
+F mkopcodeh.awk a80e53c2f41cd89b1355c2e3d9389e3f6f8e017d
 F mkso.sh 7b67da1d63070875ba948e749aee9ef50ce36e3d
 F publish.sh 72bde067dda3fc2d33e92f20253b924e3b97da30
 F spec.template b2f6c4e488cbc3b993a57deba22cbc36203c4da3
@@ -33,7 +34,7 @@ F src/btree.h 94dfec0a1722d33359b23e7e310f2b64ffedf029
 F src/build.c 2ed6d9c26ad736142012bc99898869db17337121
 F src/date.c 93927e2d1ffbd833fc220644896cfdc8f8d4af34
 F src/delete.c d862b383a9abc0b79f4588783c2619fe52d74ea7
-F src/expr.c f255c5c56c0371cb2955cbc2733621051e4f79f8
+F src/expr.c 2f492bf532d700bd2c38e16caa49048535e8ed27
 F src/func.c 1fbc5256639586573fd0e70814d6dcd8bc10afc1
 F src/hash.c a97721a55440b7bea31ffe471bb2f6b4123cddd5
 F src/hash.h 1b0c445e1c89ff2aaad9b4605ba61375af001e84
@@ -53,14 +54,14 @@ F src/os_win.c 9482dfc92f289b68205bb2c9315757c7e3946bfb
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
 F src/pager.c d3688828d314135ef0cd87b4d892805136c4168f
 F src/pager.h 67739fe649f33be55dba522ca8a9cc4e42d14f71
-F src/parse.y 968231351dd13ef6ee544336295db54708c22faf
+F src/parse.y eb4920f637b4e44e038220e67dac07854bfd6325
 F src/pragma.c 45978cc82fdf91f00d024a8e875c2b679fbce488
 F src/printf.c 40770e1f553612d13dfc86d236086e69baa62fe1
 F src/random.c eff68e3f257e05e81eae6c4d50a51eb88beb4ff3
 F src/select.c 96b1489111abe9b584be2f2cce26ad6f2d425b4e
 F src/shell.c 0856973c2b94e22664bc43f398ba3fc22d5e080c
 F src/sqlite.h.in 9bb76ff9e79ee72e6d529ff6ab1c252d513c3864
-F src/sqliteInt.h 5c406ebc830c5129748b77539283c0e20f978887
+F src/sqliteInt.h bfb12f1da75b2a8f5c88c9c3050343571def65b9
 F src/table.c 25b3ff2b39b7d87e8d4a5da0713d68dfc06cbee9
 F src/tclsqlite.c 0302e3f42f015d132d1291f3388c06e86c24a008
 F src/test1.c 3d78e5d827bf5d037f697c233c5934d45af46cb5
@@ -74,7 +75,7 @@ F src/update.c 7157084216c4b02a23cdb23eb6d246aa9034fa4d
 F src/utf.c f4f83acd73389090e32d6589d307fc55d794c7ed
 F src/util.c f4ab796b9def353feed2191d7ce8e39a0f5059cd
 F src/vacuum.c 257de36230cb988842f66eb08dc6c0250b8e05f3
-F src/vdbe.c 0542852785220807feb02b9dee1150ac2e592c8d
+F src/vdbe.c 49d4bda66884b1017e11962c7fb7eaf15b436be8
 F src/vdbe.h 067ca8d6750ba4f69a50284765e5883dee860181
 F src/vdbeInt.h 6017100adff362b8dfa37a69e3f1431f084bfa5b
 F src/vdbeapi.c 81ab9e84c55f5762f552904e6e5d309269b02017
@@ -248,7 +249,7 @@ F www/tclsqlite.tcl 560ecd6a916b320e59f2917317398f3d59b7cc25
 F www/vdbe.tcl 59288db1ac5c0616296b26dce071c36cb611dfe9
 F www/version3.tcl 092a01f5ef430d2c4acc0ae558d74c4bb89638a0
 F www/whentouse.tcl a8335bce47cc2fddb07f19052cb0cb4d9129a8e4
-P 4493e287809874fabeddf5ca9045065a30790f2f
-R ebf4aac4c1a61ea57872e563bbdb1393
+P c4697503d0ad080290b91e96dfc9a1a63f2df7e6
+R 7fe455a514dce92e3703ce1da8317d3a
 U drh
-Z 44aded0ba9c92340348fe0ad36d9356d
+Z 28445a4252d9b9c0f55f4514219ea5c1
diff --git a/manifest.uuid b/manifest.uuid
index 1525b3ca0..40870d193 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c4697503d0ad080290b91e96dfc9a1a63f2df7e6
\ No newline at end of file
+4c817e3f293a9c1365e632f7dc13ae440263332a
\ No newline at end of file
diff --git a/mkopcodeh.awk b/mkopcodeh.awk
new file mode 100644
index 000000000..49e2498b3
--- /dev/null
+++ b/mkopcodeh.awk
@@ -0,0 +1,45 @@
+#!/usr/bin/awk -f
+#
+# This AWK script scans a concatenation of the parse.h output file from the
+# parser and the vdbe.c source file in order to generate the opcodes numbers
+# for all opcodes.  
+#
+# The lines of the vdbe.c that we are interested in are of the form:
+#
+#       case OP_aaaa:      /* same as TK_bbbbb */
+#
+# The TK_ comment is optional.  If it is present, then the value assigned to
+# the OP_ is the same as the TK_ value.  If missing, the OP_ value is assigned
+# a small integer that is different from every other OP_ value.
+#
+
+# Remember the TK_ values from the parse.h file
+/^#define TK_/ {
+  tk[$2] = $3
+}
+
+# Scan for "case OP_aaaa:" lines in the vdbe.c file
+/^case OP_/ {
+  name = $2
+  gsub(/:/,"",name)
+  op[name] = -1
+  for(i=3; i<NF-2; i++){
+    if($i=="same" && $(i+1)=="as"){
+      op[name] = tk[$(i+2)]
+      used[op[name]] = 1
+    }
+  }
+}
+
+# Assign numbers to all opcodes and output the result.
+END {
+  cnt = 0
+  for(name in op){
+    if( op[name]<0 ){
+      cnt++
+      while( used[cnt] ) cnt++
+      op[name] = cnt
+    }
+    printf "#define %-30s %d\n", name, op[name]
+  }
+}
diff --git a/src/expr.c b/src/expr.c
index a07fdcd00..75167579b 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -12,7 +12,7 @@
 ** This file contains routines used for analyzing expressions and
 ** for generating VDBE code that evaluates expressions in SQLite.
 **
-** $Id: expr.c,v 1.165 2004/09/25 13:12:15 drh Exp $
+** $Id: expr.c,v 1.166 2004/10/04 13:19:24 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -1180,41 +1180,19 @@ static void codeInteger(Vdbe *v, const char *z, int n){
 /*
 ** Generate code into the current Vdbe to evaluate the given
 ** expression and leave the result on the top of stack.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
 */
 void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
   Vdbe *v = pParse->pVdbe;
   int op;
   if( v==0 || pExpr==0 ) return;
-  switch( pExpr->op ){
-    case TK_PLUS:     op = OP_Add;      break;
-    case TK_MINUS:    op = OP_Subtract; break;
-    case TK_STAR:     op = OP_Multiply; break;
-    case TK_SLASH:    op = OP_Divide;   break;
-    case TK_AND:      op = OP_And;      break;
-    case TK_OR:       op = OP_Or;       break;
-    case TK_LT:       op = OP_Lt;       break;
-    case TK_LE:       op = OP_Le;       break;
-    case TK_GT:       op = OP_Gt;       break;
-    case TK_GE:       op = OP_Ge;       break;
-    case TK_NE:       op = OP_Ne;       break;
-    case TK_EQ:       op = OP_Eq;       break;
-    case TK_ISNULL:   op = OP_IsNull;   break;
-    case TK_NOTNULL:  op = OP_NotNull;  break;
-    case TK_NOT:      op = OP_Not;      break;
-    case TK_UMINUS:   op = OP_Negative; break;
-    case TK_BITAND:   op = OP_BitAnd;   break;
-    case TK_BITOR:    op = OP_BitOr;    break;
-    case TK_BITNOT:   op = OP_BitNot;   break;
-    case TK_LSHIFT:   op = OP_ShiftLeft;  break;
-    case TK_RSHIFT:   op = OP_ShiftRight; break;
-    case TK_REM:      op = OP_Remainder;  break;
-    case TK_FLOAT:    op = OP_Real;       break;
-    case TK_STRING:   op = OP_String8;    break;
-    case TK_BLOB:     op = OP_HexBlob;    break;
-    case TK_CONCAT:   op = OP_Concat;     break;
-    default: op = 0; break;
-  }
-  switch( pExpr->op ){
+  op = pExpr->op;
+  switch( op ){
     case TK_COLUMN: {
       if( pParse->useAgg ){
         sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
@@ -1236,11 +1214,14 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
     }
     case TK_FLOAT:
     case TK_STRING: {
+      assert( TK_FLOAT==OP_Real );
+      assert( TK_STRING==OP_String8 );
       sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z, pExpr->token.n);
       sqlite3VdbeDequoteP3(v, -1);
       break;
     }
     case TK_BLOB: {
+      assert( TK_BLOB==OP_HexBlob );
       sqlite3VdbeOp3(v, op, 0, 0, pExpr->token.z+1, pExpr->token.n-1);
       sqlite3VdbeDequoteP3(v, -1);
       break;
@@ -1262,6 +1243,12 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
     case TK_GE:
     case TK_NE:
     case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
       sqlite3ExprCode(pParse, pExpr->pLeft);
       sqlite3ExprCode(pParse, pExpr->pRight);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
@@ -1279,6 +1266,17 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
     case TK_LSHIFT:
     case TK_RSHIFT: 
     case TK_CONCAT: {
+      assert( TK_AND==OP_And );
+      assert( TK_OR==OP_Or );
+      assert( TK_PLUS==OP_Add );
+      assert( TK_MINUS==OP_Subtract );
+      assert( TK_REM==OP_Remainder );
+      assert( TK_BITAND==OP_BitAnd );
+      assert( TK_BITOR==OP_BitOr );
+      assert( TK_SLASH==OP_Divide );
+      assert( TK_LSHIFT==OP_ShiftLeft );
+      assert( TK_RSHIFT==OP_ShiftRight );
+      assert( TK_CONCAT==OP_Concat );
       sqlite3ExprCode(pParse, pExpr->pLeft);
       sqlite3ExprCode(pParse, pExpr->pRight);
       sqlite3VdbeAddOp(v, op, 0, 0);
@@ -1303,6 +1301,8 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
     }
     case TK_BITNOT:
     case TK_NOT: {
+      assert( TK_BITNOT==OP_BitNot );
+      assert( TK_NOT==OP_Not );
       sqlite3ExprCode(pParse, pExpr->pLeft);
       sqlite3VdbeAddOp(v, op, 0, 0);
       break;
@@ -1310,13 +1310,15 @@ void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
     case TK_ISNULL:
     case TK_NOTNULL: {
       int dest;
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
       sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
       sqlite3ExprCode(pParse, pExpr->pLeft);
       dest = sqlite3VdbeCurrentAddr(v) + 2;
       sqlite3VdbeAddOp(v, op, 1, dest);
       sqlite3VdbeAddOp(v, OP_AddImm, -1, 0);
+      break;
     }
-    break;
     case TK_AGG_FUNCTION: {
       sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
       break;
@@ -1503,23 +1505,19 @@ int sqlite3ExprCodeExprList(
 **
 ** If the expression evaluates to NULL (neither true nor false), then
 ** take the jump if the jumpIfNull flag is true.
+**
+** This code depends on the fact that certain token values (ex: TK_EQ)
+** are the same as opcode values (ex: OP_Eq) that implement the corresponding
+** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
+** the make process cause these values to align.  Assert()s in the code
+** below verify that the numbers are aligned correctly.
 */
 void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
   Vdbe *v = pParse->pVdbe;
   int op = 0;
   if( v==0 || pExpr==0 ) return;
-  switch( pExpr->op ){
-    case TK_LT:       op = OP_Lt;       break;
-    case TK_LE:       op = OP_Le;       break;
-    case TK_GT:       op = OP_Gt;       break;
-    case TK_GE:       op = OP_Ge;       break;
-    case TK_NE:       op = OP_Ne;       break;
-    case TK_EQ:       op = OP_Eq;       break;
-    case TK_ISNULL:   op = OP_IsNull;   break;
-    case TK_NOTNULL:  op = OP_NotNull;  break;
-    default:  break;
-  }
-  switch( pExpr->op ){
+  op = pExpr->op;
+  switch( op ){
     case TK_AND: {
       int d2 = sqlite3VdbeMakeLabel(v);
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2, !jumpIfNull);
@@ -1542,6 +1540,12 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
     case TK_GE:
     case TK_NE:
     case TK_EQ: {
+      assert( TK_LT==OP_Lt );
+      assert( TK_LE==OP_Le );
+      assert( TK_GT==OP_Gt );
+      assert( TK_GE==OP_Ge );
+      assert( TK_EQ==OP_Eq );
+      assert( TK_NE==OP_Ne );
       sqlite3ExprCode(pParse, pExpr->pLeft);
       sqlite3ExprCode(pParse, pExpr->pRight);
       codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
@@ -1549,6 +1553,8 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
     }
     case TK_ISNULL:
     case TK_NOTNULL: {
+      assert( TK_ISNULL==OP_IsNull );
+      assert( TK_NOTNULL==OP_NotNull );
       sqlite3ExprCode(pParse, pExpr->pLeft);
       sqlite3VdbeAddOp(v, op, 1, dest);
       break;
@@ -1597,17 +1603,38 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
   Vdbe *v = pParse->pVdbe;
   int op = 0;
   if( v==0 || pExpr==0 ) return;
-  switch( pExpr->op ){
-    case TK_LT:       op = OP_Ge;       break;
-    case TK_LE:       op = OP_Gt;       break;
-    case TK_GT:       op = OP_Le;       break;
-    case TK_GE:       op = OP_Lt;       break;
-    case TK_NE:       op = OP_Eq;       break;
-    case TK_EQ:       op = OP_Ne;       break;
-    case TK_ISNULL:   op = OP_NotNull;  break;
-    case TK_NOTNULL:  op = OP_IsNull;   break;
-    default:  break;
-  }
+
+  /* The value of pExpr->op and op are related as follows:
+  **
+  **       pExpr->op            op
+  **       ---------          ----------
+  **       TK_ISNULL          OP_NotNull
+  **       TK_NOTNULL         OP_IsNull
+  **       TK_NE              OP_Eq
+  **       TK_EQ              OP_Ne
+  **       TK_GT              OP_Le
+  **       TK_LE              OP_Gt
+  **       TK_GE              OP_Lt
+  **       TK_LT              OP_Ge
+  **
+  ** For other values of pExpr->op, op is undefined and unused.
+  ** The value of TK_ and OP_ constants are arranged such that we
+  ** can compute the mapping above using the following expression.
+  ** Assert()s verify that the computation is correct.
+  */
+  op = ((pExpr->op+(TK_ISNULL&1))^1)-(TK_ISNULL&1);
+
+  /* Verify correct alignment of TK_ and OP_ constants
+  */
+  assert( pExpr->op!=TK_ISNULL || op==OP_NotNull );
+  assert( pExpr->op!=TK_NOTNULL || op==OP_IsNull );
+  assert( pExpr->op!=TK_NE || op==OP_Eq );
+  assert( pExpr->op!=TK_EQ || op==OP_Ne );
+  assert( pExpr->op!=TK_LT || op==OP_Ge );
+  assert( pExpr->op!=TK_LE || op==OP_Gt );
+  assert( pExpr->op!=TK_GT || op==OP_Le );
+  assert( pExpr->op!=TK_GE || op==OP_Lt );
+
   switch( pExpr->op ){
     case TK_AND: {
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
diff --git a/src/parse.y b/src/parse.y
index 8d42dfd47..5999e2146 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -14,7 +14,7 @@
 ** the parser.  Lemon will also generate a header file containing
 ** numeric codes for all of the tokens.
 **
-** @(#) $Id: parse.y,v 1.139 2004/09/30 14:22:47 drh Exp $
+** @(#) $Id: parse.y,v 1.140 2004/10/04 13:19:24 drh Exp $
 */
 %token_prefix TK_
 %token_type {Token}
@@ -137,11 +137,17 @@ id(A) ::= ID(X).         {A = X;}
 // causes them to be assigned integer values that are close together,
 // which keeps parser tables smaller.
 //
+// The token values assigned to these symbols is determined by the order
+// in which lemon first sees them.  It must be the case that ISNULL/NOTNULL,
+// NE/EQ, GT/LE, and GE/LT are separated by only a single value.  See
+// the sqlite3ExprIfFalse() routine for additional information on this
+// constraint.
+//
 %left OR.
 %left AND.
 %right NOT.
-%left ISNULL NOTNULL IS LIKE GLOB BETWEEN IN NE EQ.
-%left GT GE LT LE.
+%left IS LIKE GLOB BETWEEN IN ISNULL NOTNULL NE EQ.
+%left GT LE GE LT.
 %left BITAND BITOR LSHIFT RSHIFT.
 %left PLUS MINUS.
 %left STAR SLASH REM.
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index e8946f256..7b4c4fc0e 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -11,7 +11,7 @@
 *************************************************************************
 ** Internal interface definitions for SQLite.
 **
-** @(#) $Id: sqliteInt.h,v 1.325 2004/10/01 02:00:31 drh Exp $
+** @(#) $Id: sqliteInt.h,v 1.326 2004/10/04 13:19:24 drh Exp $
 */
 #ifndef _SQLITEINT_H_
 #define _SQLITEINT_H_
@@ -767,9 +767,9 @@ struct Token {
 struct Expr {
   u8 op;                 /* Operation performed by this node */
   char affinity;         /* The affinity of the column or 0 if not a column */
-  CollSeq *pColl;        /* The collation type of the column or 0 */
   u8 iDb;                /* Database referenced by this expression */
   u8 flags;              /* Various flags.  See below */
+  CollSeq *pColl;        /* The collation type of the column or 0 */
   Expr *pLeft, *pRight;  /* Left and right subnodes */
   ExprList *pList;       /* A list of expressions used as function arguments
                          ** or in "<expr> IN (<expr-list)" */
diff --git a/src/vdbe.c b/src/vdbe.c
index 5ec829464..327460ca2 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.415 2004/09/19 00:50:21 drh Exp $
+** $Id: vdbe.c,v 1.416 2004/10/04 13:19:24 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -184,32 +184,6 @@ static int AggInsert(Agg *p, char *zKey, int nKey){
 }
 
 /*
-** Store a pointer to the AggElem currently in focus in *ppElem. Return
-** SQLITE_OK if successful, otherwise an error-code.
-*/
-static int AggInFocus(Agg *p, AggElem **ppElem){
-  int rc;
-  int res;
-
-  if( p->pCurrent ){
-    *ppElem = p->pCurrent;
-    return SQLITE_OK;
-  }
-
-  rc = sqlite3BtreeFirst(p->pCsr, &res);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
-  if( res!=0 ){
-    rc = AggInsert(p,"",1);
-    *ppElem = p->pCurrent;
-  }else{
-    rc = sqlite3BtreeData(p->pCsr, 0, 4, (char *)ppElem);
-  }
-  return rc;
-}
-
-/*
 ** Pop the stack N times.
 */
 static void popStack(Mem **ppTos, int N){
@@ -559,7 +533,9 @@ int sqlite3VdbeExec(
 ** file looking for lines that begin with "case OP_".  The opcodes.h files
 ** will be filled with #defines that give unique integer values to each
 ** opcode and the opcodes.c file is filled with an array of strings where
-** each string is the symbolic name for the corresponding opcode.
+** each string is the symbolic name for the corresponding opcode.  If the
+** case statement is followed by a comment of the form "/# same as ... #/"
+** that comment is used to determine the particular value of the opcode.
 **
 ** Documentation about VDBE opcodes is generated by scanning this file
 ** for lines of that contain "Opcode:".  That line and all subsequent
@@ -677,7 +653,7 @@ case OP_Integer: {
 **
 ** The string value P3 is converted to a real and pushed on to the stack.
 */
-case OP_Real: {
+case OP_Real: {            /* same as TK_FLOAT */
   pTos++;
   pTos->flags = MEM_Str|MEM_Static|MEM_Term;
   pTos->z = pOp->p3;
@@ -694,7 +670,7 @@ case OP_Real: {
 ** P3 points to a nul terminated UTF-8 string. This opcode is transformed
 ** into an OP_String before it is executed for the first time.
 */
-case OP_String8: {
+case OP_String8: {         /* same as TK_STRING */
   pOp->opcode = OP_String;
 
   if( db->enc!=SQLITE_UTF8 && pOp->p3 ){
@@ -745,7 +721,7 @@ case OP_String: {
 ** The first time this instruction executes, in transforms itself into a
 ** 'Blob' opcode with a binary blob as P3.
 */
-case OP_HexBlob: {
+case OP_HexBlob: {            /* same as TK_BLOB */
   pOp->opcode = OP_Blob;
   pOp->p1 = strlen(pOp->p3)/2;
   if( pOp->p1 ){
@@ -922,7 +898,7 @@ case OP_Callback: {
 ** When P1==1, this routine makes a copy of the top stack element
 ** into memory obtained from sqliteMalloc().
 */
-case OP_Concat: {
+case OP_Concat: {           /* same as TK_CONCAT */
   char *zNew;
   int nByte;
   int nField;
@@ -1030,11 +1006,11 @@ case OP_Concat: {
 ** function before the division.  Division by zero returns NULL.
 ** If either operand is NULL, the result is NULL.
 */
-case OP_Add:
-case OP_Subtract:
-case OP_Multiply:
-case OP_Divide:
-case OP_Remainder: {
+case OP_Add:                   /* same as TK_PLUS */
+case OP_Subtract:              /* same as TK_MINUS */
+case OP_Multiply:              /* same as TK_STAR */
+case OP_Divide:                /* same as TK_SLASH */
+case OP_Remainder: {           /* same as TK_REM */
   Mem *pNos = &pTos[-1];
   assert( pNos>=p->aStack );
   if( ((pTos->flags | pNos->flags) & MEM_Null)!=0 ){
@@ -1233,10 +1209,10 @@ case OP_Function: {
 ** right by N bits where N is the top element on the stack.
 ** If either operand is NULL, the result is NULL.
 */
-case OP_BitAnd:
-case OP_BitOr:
-case OP_ShiftLeft:
-case OP_ShiftRight: {
+case OP_BitAnd:                 /* same as TK_BITAND */
+case OP_BitOr:                  /* same as TK_BITOR */
+case OP_ShiftLeft:              /* same as TK_LSHIFT */
+case OP_ShiftRight: {           /* same as TK_RSHIFT */
   Mem *pNos = &pTos[-1];
   int a, b;
 
@@ -1398,12 +1374,12 @@ case OP_MustBeInt: {
 ** the 2nd element down on the stack is greater than or equal to the
 ** top of the stack.  See the Eq opcode for additional information.
 */
-case OP_Eq:
-case OP_Ne:
-case OP_Lt:
-case OP_Le:
-case OP_Gt:
-case OP_Ge: {
+case OP_Eq:               /* same as TK_EQ */
+case OP_Ne:               /* same as TK_NE */
+case OP_Lt:               /* same as TK_LT */
+case OP_Le:               /* same as TK_LE */
+case OP_Gt:               /* same as TK_GT */
+case OP_Ge: {             /* same as TK_GE */
   Mem *pNos;
   int flags;
   int res;
@@ -1469,8 +1445,8 @@ case OP_Ge: {
 ** two values and push the resulting boolean value back onto the
 ** stack. 
 */
-case OP_And:
-case OP_Or: {
+case OP_And:              /* same as TK_AND */
+case OP_Or: {             /* same as TK_OR */
   Mem *pNos = &pTos[-1];
   int v1, v2;    /* 0==TRUE, 1==FALSE, 2==UNKNOWN or NULL */
 
@@ -1517,7 +1493,7 @@ case OP_Or: {
 ** with its absolute value. If the top of the stack is NULL
 ** its value is unchanged.
 */
-case OP_Negative:
+case OP_Negative:              /* same as TK_UMINUS */
 case OP_AbsValue: {
   assert( pTos>=p->aStack );
   if( pTos->flags & MEM_Real ){
@@ -1550,7 +1526,7 @@ case OP_AbsValue: {
 ** with its complement.  If the top of the stack is NULL its value
 ** is unchanged.
 */
-case OP_Not: {
+case OP_Not: {                /* same as TK_NOT */
   assert( pTos>=p->aStack );
   if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
   Integerify(pTos);
@@ -1566,7 +1542,7 @@ case OP_Not: {
 ** with its ones-complement.  If the top of the stack is NULL its
 ** value is unchanged.
 */
-case OP_BitNot: {
+case OP_BitNot: {             /* same as TK_BITNOT */
   assert( pTos>=p->aStack );
   if( pTos->flags & MEM_Null ) break;  /* Do nothing to NULLs */
   Integerify(pTos);
@@ -1627,7 +1603,7 @@ case OP_IfNot: {
 ** to P2.  Pop the stack P1 times if P1>0.   If P1<0 leave the stack
 ** unchanged.
 */
-case OP_IsNull: {
+case OP_IsNull: {            /* same as TK_ISNULL */
   int i, cnt;
   Mem *pTerm;
   cnt = pOp->p1;
@@ -1650,7 +1626,7 @@ case OP_IsNull: {
 ** stack if P1 times if P1 is greater than zero.  If P1 is less than
 ** zero then leave the stack unchanged.
 */
-case OP_NotNull: {
+case OP_NotNull: {            /* same as TK_NOTNULL */
   int i, cnt;
   cnt = pOp->p1;
   if( cnt<0 ) cnt = -cnt;
@@ -4241,8 +4217,7 @@ case OP_AggFocus: {
 case OP_AggSet: {
   AggElem *pFocus;
   int i = pOp->p2;
-  rc = AggInFocus(&p->agg, &pFocus);
-  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+  pFocus = p->agg.pCurrent;
   assert( pTos>=p->aStack );
   if( pFocus==0 ) goto no_mem;
   assert( i>=0 && i<p->agg.nMem );
@@ -4260,8 +4235,7 @@ case OP_AggSet: {
 case OP_AggGet: {
   AggElem *pFocus;
   int i = pOp->p2;
-  rc = AggInFocus(&p->agg, &pFocus);
-  if( rc!=SQLITE_OK ) goto abort_due_to_error;
+  pFocus = p->agg.pCurrent;
   if( pFocus==0 ) goto no_mem;
   assert( i>=0 && i<p->agg.nMem );
   pTos++;