🚀 go-pugleaf

I have found two bugs in VC relating to the "@AVG" function.  The first
is an error in the gram.y file causing the function to be incorrectly
recognized by the string "@AVE" instead of the correct "@AVG".  The
save file routine (P command) writes the average function out as "@avg"
which is subsequently not recognized when the save file is read in (G
command).  The second bug occurs in the averaging routine itself when
no valid values are found in the specified range.  This causes a divide
by 0 error which aborts execution on many machines.  Following are the
context diffs for "gram.y" and "interp.c"

diff -c OLD/gram.y NEW/gram.y
*** OLD/gram.y	Fri Jan 16 22:29:56 1987
--- NEW/gram.y	Fri Jan 16 22:29:15 1987
***************
*** 46,52
  %token K_FIXED
  %token K_SUM
  %token K_PROD
! %token K_AVE
  
  %left '?' ':'
  %left '|'

--- 46,52 -----
  %token K_FIXED
  %token K_SUM
  %token K_PROD
! %token K_AVG
  
  %left '?' ':'
  %left '|'
***************
*** 86,92
  				{ $$ = new (O_REDUCE('+'), $4, $6); }
  	|       '@' K_PROD '(' var ':' var ')' 
  				{ $$ = new (O_REDUCE('*'), $4, $6); }
! 	|       '@' K_AVE '(' var ':' var ')' 
  				{ $$ = new (O_REDUCE('a'), $4, $6); }
  	|	'(' e ')'	{ $$ = $2; }
  	|	'+' term	{ $$ = $2; }

--- 86,92 -----
  				{ $$ = new (O_REDUCE('+'), $4, $6); }
  	|       '@' K_PROD '(' var ':' var ')' 
  				{ $$ = new (O_REDUCE('*'), $4, $6); }
! 	|       '@' K_AVG '(' var ':' var ')' 
  				{ $$ = new (O_REDUCE('a'), $4, $6); }
  	|	'(' e ')'	{ $$ = $2; }
  	|	'+' term	{ $$ = $2; }
diff -c OLD/interp.c NEW/interp.c
*** OLD/interp.c	Fri Jan 16 22:30:31 1987
--- NEW/interp.c	Fri Jan 16 22:29:15 1987
***************
*** 60,66
  		count++;
  	    }
  
!     return (v / (double)count);
  }
  
  double eval(e)

--- 60,69 -----
  		count++;
  	    }
  
!     if(count == 0)
! 	return 0.0;
!     else
! 	return (v / (double)count);
  }
  
  double eval(e)
-- 
                Kevin C. Rushforth
                Evans & Sutherland Computer Corporation

UUCP Address:   {ihnp4,decvax}!decwrl!esunix!rushfort
Alternate:      {ihnp4,seismo}!utah-cs!utah-gr!uplherc!esunix!rushfort