/* Copyright (C) 1994 by Thomas Glen Smith.  All Rights Reserved. */
/* funcmain APL2 V1.0.0 ************************************************
* Called by execnila, execdyan, and execmons to execute niladic,       *
* monadic, and dyadic user functions.                                  *
***********************************************************************/
#define INCLUDES APLMEM+STRING+APLCB+APLTOKEN+APLFUNCI+TREE
#include "includes.h"
Aplcb funcmain(fp,left,rite)
Aplfunc fp; /* Function definition structure. */
Aplcb left,rite; /* Operands, or may be NULL. */
{
	Aplclsub; Avlsrch; Execterm; Expunge; Funcexec; Funcinit; Funcopy;
	Pop; Treeroot;
	extern int aplerr, indxorg;
	extern double fuzz;
	extern Treelist treehdr;
	Treelist root;
	Avlnode p;
     Aplcb out=NULL;
     int flagsave;

     flagsave = fp->funcflag & APLFUNC_IN_USE;
     if (flagsave) fp = funcopy(fp);
     else fp->funcflag |= APLFUNC_IN_USE;
	root = treeroot(fp); /* add new root for local variables */
	if (root == NULL) return(NULL); /* out of memory? */
	root->fuzzhold = fuzz; /* save for potential restore */
	root->indxhold = indxorg; /* save for potential restore */
	funcinit(fp,left,rite); /*init local var tree*/
	if (aplerr == 0)
		funcexec(1); /* commence function execution */
	fp = treehdr->avlfun; /* May have been replaced by an edit. */
	if (aplerr == 0 && fp->functype & RETVAL) { /* obtain result */
		p = avlsrch(treehdr->avlhdr,
			fp->funcvars->token_ptr.token_string);
		out = p->avlleaf;
		p->avlleaf = NULL;
		if (out == NULL) aplerr = 98;
		else out->aplflags |= APLTEMP; /* mark temporary */
	}
	while (NULL != treehdr->avlexec)
		execterm(); /* Go free execstk element. */
	root = pop(&treehdr); /* pop treehdr stack */
	aplclsub(root->avlhdr); /* free tree */
	if (NULL != root->avlfname)
		free(root->avlfname); /* free function name */
	if (root->fuzzsave) fuzz = root->fuzzhold; /* restore */
	if (root->indxsave) indxorg = root->indxhold; /* restore */
	free(root); /* free root */
     if (flagsave) expunge(fp);
     else fp->funcflag -= APLFUNC_IN_USE;
	return(out); /* return result, if any */
}