SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.163 2004/09/19 02:15:25 drh Exp $
** $Id: expr.c,v 1.164 2004/09/24 12:24:07 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

char const *sqlite3AffinityString(char affinity){
  switch( affinity ){
    case SQLITE_AFF_INTEGER: return "i";

    return 0;
  }
  pNew->op = op;
  pNew->pLeft = pLeft;
  pNew->pRight = pRight;
  if( pToken ){
    assert( pToken->dyn==0 );
    pNew->token = *pToken;
    pNew->span = *pToken;
    pNew->span = pNew->token = *pToken;
  }else{
    assert( pNew->token.dyn==0 );
    assert( pNew->token.z==0 );
    assert( pNew->token.n==0 );
    if( pLeft && pRight ){
      sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
  }else if( pLeft && pRight ){
    sqlite3ExprSpan(pNew, &pLeft->span, &pRight->span);
    }else{
      pNew->span = pNew->token;
    }
  }
  return pNew;
}

/*
** Join two expressions using an AND operator.  If either expression is
** NULL, then just return the other expression.

** text between the two given tokens.
*/
void sqlite3ExprSpan(Expr *pExpr, Token *pLeft, Token *pRight){
  assert( pRight!=0 );
  assert( pLeft!=0 );
  if( !sqlite3_malloc_failed && pRight->z && pLeft->z ){
    assert( pLeft->dyn==0 || pLeft->z[pLeft->n]==0 );
    if( pLeft->z[pLeft->n]!=0 && pRight->dyn==0 ){
    if( pLeft->dyn==0 && pRight->dyn==0 ){
      pExpr->span.z = pLeft->z;
      pExpr->span.n = pRight->n + Addr(pRight->z) - Addr(pLeft->z);
    }else{
      pExpr->span.z = 0;
    }
  }
}

    pTo->dyn = 1;
  }else{
    pTo->z = 0;
  }
}
ExprList *sqlite3ExprListDup(ExprList *p){
  ExprList *pNew;
  struct ExprList_item *pItem;
  struct ExprList_item *pItem, *pOldItem;
  int i;
  if( p==0 ) return 0;
  pNew = sqliteMalloc( sizeof(*pNew) );
  if( pNew==0 ) return 0;
  pNew->nExpr = pNew->nAlloc = p->nExpr;
  pNew->a = pItem = sqliteMalloc( p->nExpr*sizeof(p->a[0]) );
  if( pItem==0 ){
    sqliteFree(pNew);
    return 0;
  } 
  pOldItem = p->a;
  for(i=0; i<p->nExpr; i++, pItem++){
  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
    Expr *pNewExpr, *pOldExpr;
    pItem->pExpr = pNewExpr = sqlite3ExprDup(pOldExpr = p->a[i].pExpr);
    pItem->pExpr = pNewExpr = sqlite3ExprDup(pOldExpr = pOldItem->pExpr);
    if( pOldExpr->span.z!=0 && pNewExpr ){
      /* Always make a copy of the span for top-level expressions in the
      ** expression list.  The logic in SELECT processing that determines
      ** the names of columns in the result set needs this information */
      sqlite3TokenCopy(&pNewExpr->span, &pOldExpr->span);
    }
    assert( pNewExpr==0 || pNewExpr->span.z!=0 
            || pOldExpr->span.z==0 || sqlite3_malloc_failed );
    pItem->zName = sqliteStrDup(p->a[i].zName);
    pItem->sortOrder = p->a[i].sortOrder;
    pItem->isAgg = p->a[i].isAgg;
    pItem->zName = sqliteStrDup(pOldItem->zName);
    pItem->sortOrder = pOldItem->sortOrder;
    pItem->isAgg = pOldItem->isAgg;
    pItem->done = 0;
  }
  return pNew;
}
SrcList *sqlite3SrcListDup(SrcList *p){
  SrcList *pNew;
  int i;

  }
  switch( pExpr->op ){
    case TK_COLUMN: {
      if( pParse->useAgg ){
        sqlite3VdbeAddOp(v, OP_AggGet, 0, pExpr->iAgg);
      }else if( pExpr->iColumn>=0 ){
        sqlite3VdbeAddOp(v, OP_Column, pExpr->iTable, pExpr->iColumn);
#ifndef NDEBUG
        if( pExpr->span.z && pExpr->span.n>0 && pExpr->span.n<100 ){
        VdbeComment((v, "# %T", &pExpr->span));
          VdbeComment((v, "# %T", &pExpr->span));
        }
#endif
      }else{
        sqlite3VdbeAddOp(v, OP_Recno, pExpr->iTable, 0);
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, pExpr->token.z, pExpr->token.n);