--- capa/capa51/pProj/capaUnit.c	2000/03/22 21:08:03	1.4
+++ capa/capa51/pProj/capaUnit.c	2023/08/04 18:09:55	1.14
@@ -1,13 +1,37 @@
+/* functions to handle the unit parser/comparison engine
+   Copyright (C) 1992-2000 Michigan State University
+
+   The CAPA system is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The CAPA system is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with the CAPA system; see the file COPYING.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   As a special exception, you have permission to link this program
+   with the TtH/TtM library and distribute executables, as long as you
+   follow the requirements of the GNU GPL in regard to all of the
+   software in the executable aside from TtH/TtM.
+*/
 
 /* =||>|===================== capaUnit.c   =====================|<||= */
 /*   created by Isaac Tsai   1997                                    */
-/*   copyrighted by Isaac Tsai 1997, 1998, 1999                      */
+/*   by Isaac Tsai 1997, 1998, 1999                      */
 /* =||>|========================================================|<||= */
 #include <stdio.h>        /* fopen()  */
 #include <stdlib.h>
 #include <ctype.h>        /* isalnum()   */
 #include <string.h>
 #include <math.h>
+#include <float.h>
 
 #include "capaParser.h"
 
@@ -703,22 +727,24 @@ process_op(int op)
   }
 }
 
-void
+Unit_t*
 process_utree(Unit_t *t)
 {
   Ptopidx=0;
   postwalk_utree(t);
   if( Ptopidx == 1 ) {
-    /* printf("Correctly parsed!\n"); */
-    printf("Unit:%s\n",Sbuf);
+    //fprintf(stderr,"Correctly parsed!\n");
+    //fprintf(stderr,"Unit:%s\n",Sbuf);
     simplify_unit(Pstack[Ptopidx]);
-    Pstack[Ptopidx]->u_symbol[0]='\0';
-    /*sprintf(Pstack[Ptopidx]->u_symbol,"");*/
-    print_unit_t(Pstack[Ptopidx]);
-    u_find_name(Pstack[Ptopidx]);
-    print_matches(Pstack[Ptopidx]);
-    free_utree(t);
+    //Pstack[Ptopidx]->u_symbol[0]='\0';
+    //fprintf(stderr,Pstack[Ptopidx]->u_symbol,"");
+    //print_unit_t(Pstack[Ptopidx]);
+    //u_find_name(Pstack[Ptopidx]);
+    //print_matches(Pstack[Ptopidx]);
+    return(Pstack[Ptopidx]);
+    //free_utree(t);
   }
+  return(t);
 }
 
 /* ============================================================== */
@@ -757,17 +783,17 @@ int  check_correct_unit(char *u_symb,Uni
 	  (Pstack[Ptopidx]->u_count == t->u_count) ) { /* has unit */
 	*scale = units_ratio(Pstack[Ptopidx], t);
 	if( *scale == 0.0 ) {
-	  result = UNIT_FAIL;
+	  result = UNIT_IRRECONCIBLE;
 	}
 	free_utree(ap);
       } else {
-	result = UNIT_FAIL;
+	result = UNIT_INVALID_STUDENT3;
       }
     } else { /* invalid unit representation */
-      result = UNIT_FAIL;
+      result = UNIT_INVALID_STUDENT2;
     }
   } else {
-    result = UNIT_FAIL;
+    result = UNIT_INVALID_STUDENT1;
   }
 #ifdef UNIT_DBUG
   fclose(ufp);
@@ -888,8 +914,9 @@ u_copy_unit(Unit_t *a_p, Unit_t *b_p, do
       a_p->u_count++;
     } else if( b_p->u_type == U_DERIVED) {
       /* derived units but without any units elements (scalar) */
-      /* do nothing, ignore this units  WE REALLY MEAN THIS DON'T DO THE NEXT LINE!*/
       /*a_p->u_count++;*/
+      scale = pow(b_p->u_scale, exp_scale);
+      a_p->u_scale = a_p->u_scale * scale;
     } else if( b_p->u_type == U_CONSTANT ) {
       scale = pow(b_p->u_scale, exp_scale);
       a_p->u_scale = a_p->u_scale * scale;
@@ -1383,10 +1410,10 @@ u_insert_derived(n_p,s_p,c_p,u_p)char  *
   strcpy(new_p->u_comment,c_p);
   
   simplify_unit(new_p);
-  /*
+#ifdef UNIT_DBUG
   printf("Derived Unit:%s\n",new_p->u_name);
   print_unit_t(new_p); 
-  */
+#endif
   if (c_result < 0 ) {
     new_p->u_left = t->u_left; new_p->u_right = t;
     t->u_left = NULL;
@@ -1719,18 +1746,18 @@ p_new_unit(Unit_t *left_p, Unit_t *right
             err_code = 3;
 	    cu_p->u_type   = U_UNKNOWN;
           }
-        } else {
+        } else { /* symb_str is not in <prefix><units> form */
           /* printf("<<%s>>", symb_str); */
           err_code = 2;
 	  cu_p->u_type   = U_UNKNOWN;
         }
       } else {/* len == 1 */
-        /* printf(" not found\n"); */
+        /* printf(" not found in symbol tree \n"); */
         err_code = 1;
 	cu_p->u_type   = U_UNKNOWN;
       }
     }
-  } else {
+  } else { /* why would we have a length less than zero symb_str ? */
     err_code = 4;
   }