embed.cpp

eC++编译器源码

#include <rdbCom.h>
#include <RDB.h>
#include <RInterpret.h>
#include <SYSTEM.h>
#include <RTuple.h>
#include <InOut.h>

SortLists sl;
Ref ref;
char kode[32];

SortList slr;
Relation r;
char name[10];
pTuple codeVec[16];
unsigned int i;

boolean AddAllAttrs(Relation r, SortList &s, RFs &keys)
{
      unsigned int i, asize;
      Attribute aptr;
      char aname[32], atype[32], avalue[32];

      i = 0;
      keys[0].relation = 0;

      for( ;; ) {           /*iterate over all attributes of relation r*/
        aptr = RGetAttr(r, i, aname, atype, asize);  /*retrieve name,type name, field width*/
        if ( aptr == Attribute(NULL) ) { break; }
        INC(keys[0].relation);  /*create an output permutation vector; [0] contains count of fields*/
        keys[i+1].relation = 0;
        keys[i+1].field = i;
        atype = "ascending";
        if ( ! RAddKey(s, aname, atype) ) { return false; }
        INC(i);
      }
      return i!=0;
};

char PN[32];

void main(void)
{ char ncode[4];
  ncode[0] = '\0';
  for ( ;; ) {       //   LOOP
   WriteLn();
   WriteString("enter pn e.g. p1 or p2> ");
   ReadString(PN);

   /*************** select sn from spj where pn="p2"; ****************/

   name = "spj";
   ref.rcnt = 0;
   ref.keys[0].relation = 1;   /* the output permutation vector */
   ref.keys[1].relation = 0;   /* sn refers to relation 0 in the SortLists */
   ref.keys[1].field = 0;      /* and sn is field 0 in spj, pn 1, jn 2 etc.*/

   r = RFind(name);   /* make the relation accessible to the program*/
   if ( r == Relation(NULL) ) { break; }

   sl = NULL;
   ROpenSortLists(sl); /* a list of permutation vectors on each relation*/
   if ( sl == NULL ) { break; }
   slr = NULL;
   ROpenSort(r, slr);          /* a permutation vector on a relation */
   if ( slr == NULL ) { break; }

   if ( AddAllAttrs(r, slr, ref.keys)==false ) { break; }  
   RAddSortList(sl, slr);

   kode[0] = lkf;
   kode[1] = '0';
   kode[2] = '0';
   kode[3] = '0';
   kode[4] = '1';
   kode[5] = lis;
   kode[6] = '0';
   kode[7] = '2';
   kode[8] = PN[0];
   kode[9] = PN[1];
   kode[10] = cmp;
   kode[11] = eql;
   kode[12] = stop;
   kode[13] = '\0';    /* OR if you are in the know*/

   for ( i = 1 ; i <= ref.keys[0].relation ; i = i + 1 ) {  /*number of output fields*/
     codeVec[i] = ADR(ncode);
   }
   codeVec[0] = ADR(kode);

     if ( Project(sl, ref, codeVec, "rdbcur", true) == 0 ) {
     WriteString("no matching part number");
     WriteLn();
     break;
   } 
   RCloseSortLists(sl);
   RCDone(r);

   /********************************* join rdbcur,s into temp; */

   if ( Join("rdbcur", "s", "temp") == 0 ) {   /* pretty simple!! */
      WriteString("itegrity problem: missing supplier number");
      WriteLn();
      break;
   }

   /********************************** print * from temp; */
  
   name = "temp";

   r = RFind(name);    /* make the relation accessible to the program*/
   if ( r == Relation(NULL) ) { break; }
//   Resize(r, 300);     /*just for fun, add more tuples to temp*/

   sl = NULL;
   ROpenSortLists(sl); /* repeat the same operations as for Select */
   if ( sl == NULL ) { break; }
   slr = NULL;
   ROpenSort(r, slr);
   if ( slr == NULL ) { break; }

   if ( AddAllAttrs(r, slr, ref.keys)==false ) { return; }
   RAddSortList(sl, slr);
   ref.rcnt = 0;
    
   //kode = "t!";    /* just select all attributes from every tuple */
   kode[0] = 't';
   kode[1] = '!';
   kode[2] = '\0';
   for ( i = 1 ; i <= 10; i = i + 1 ) {  /*number of output fields*/
        codeVec[i] = ADR(ncode);
   }
   codeVec[0] = ADR(kode);

   WriteLn();
   WriteString("Here are the suppliers for jobs that use part ");
   WriteString(PN);  WriteLn();

   if ( Print(sl, ref, codeVec, 1,"txt",true) == 0 ) {
      WriteString("nothing printed");
      WriteLn();
   }

   RCloseSortLists(sl);
   RCDone(r);
 }   //   LOOP
};