/* Copyright (C) 1993 by Thomas Glen Smith.	All Rights Reserved. */
/* picks APL2 V1.0.0 ***************************************************
* Called by execspez to handle selective specification where the form  *
* is (l`Xr)#n, and `X is RIGHT_SHOE (pick).						 *
***********************************************************************/
#define INCLUDES APLCHDEF+APLTOKEN+APLCB+TREE
#include "includes.h"
Aplcb picks(axistok, ritename, rite)
Apltoken axistok; /* token for x in e.g. (l`X[x]r)#n	*/
char *ritename;   /* name for r in e.g. (l`Xr)#n	    */
Aplcb rite;	   /* Aplcb for r in e.g. (l`Xr)#n		*/
{
	Aplnest; Assign; Enlistd; Execexed; Execexek; Execfree; Execgetp;
     Exectok; Lifo; Pick; Pop;
	extern Treelist treehdr;
	extern int aplerr;
	Aplcb left=NULL, new=NULL, out=NULL;
     Apltoken op;
	int i, off;

	for (;;) { /* lets me use break */
		execexed(); /* mainline expression evaluation for left */
		left = execgetp(execexek());
		if (axistok) { aplerr = 89; /* bad axis */ break; }
		if (treehdr->avlexec->avloprst) {
			off = treehdr->avlexec->avloprst->token_offset;
			new = execgetp(pop(&(treehdr->avlexec->avloprst)));
		}
		else aplerr = 59; /* new not found */
		if (aplerr) break;
          if (left->aplcount == 0) {
          	endoper(left); left = NULL;
          	out = assign(ritename,new); /* total replacement */
          }
          else {
	          if (!(rite->aplflags & APLAPL))
               	if (new->aplrank)
                    	rite = assign(ritename,aplnest(rite));
               	else {
					i = rite->aplflags & APLTEMP;
					if (!matchok(&rite,&new,APLMASK+APLAPL))
                         	break;
					if (i==0 && (rite->aplflags & APLTEMP))
						rite = assign(ritename,rite);
	          	}
			out = pick(left,rite,new);
          }
          left = rite = new = NULL;
		if (aplerr) break;
		op = lifo(&(treehdr->avlexec->avloprst), exectok(out,off));
		break;
	}
	endoper(left);
	endoper(rite);
     endoper(new);
	return(NULL);
}