#419 treatment of REF CHAR() in expressions

[Rainer Müller]

the language report states that REF CHAR() objects may be used like CHAR(x) objects, with the restriction that the length is done at run-time

Sketch of a possible implementation

Example source fragment

DCL (rc1, rc2) REF CHAR();
DCL (c1,c2) CHAR(2) INIT('ab','cd');
...
! rc1 and rc2 contain some data
IF rc1 CAT c1 < c2 CAT rc2 THEN ... FIN;

In order to evaluate the comparison, we must create storage for all expression containing REF CHAR()

bool comparisonResult;
{ // create new block for local variables
    // calculate the required length, I use int for simplicity
   int l1;
   l1 = rc1.getCurrent() + sizeof(c1);
   l2 = sizeof(c2) + rc2.getCurrent();
   // create local storage
   char h1[l1],h2[l2];
   // perform the CAT operations
   RefChar r1,r2
   r1.setWork(h1,l1);
   r1.rewind();
   r1.add(rc1);
   r1.add(c1);

   r2.setWork(h2,l2);
   r2.rewind();
   r2.add(c2);
    r2.add(rc2);

    comparisonResult = r1 < r2;
}

remark

this may be a better solution than the current implementation, if more than 1 CAT operation is used in sequence like

compeleteName = title CAT preName  CAT name;

~~~