OpenEuphoria

Re: problems with the scoping in eu4

• Posted by jeremy (admin) Jan 09, 2011
• 1756 views

1 while f > 0 with entry do 
2   integer sum = 0 
3   ... 
4 entry 
5   f = ... 
6   sum +=  
7 end while 

This is a coding error, somewhat like this:

integer sum 
 
if xyz > 1 then 
    sum = 0 
elsif xyz < -20 then 
    sum = 100 
end if 
 
sum += 1 

If you understand with entry and have a valid use for it, then you will not have coding errors like you illustrate above. Your example above is misusing with entry and also not understanding how scoping works in Euphoria. The sum, in that case, even if it incremented, would always be reset to zero. The way to write your loop above is:

integer sum = 0 
while f > 0 with entry do 
  ... 
entry 
  f = ... 
  sum +=  
end while 

with entry is not for every loop, but many loops it makes the code cleaner, no duplication and thus easier to understand, less potential for initial bugs and for bugs due to later maintenance. For example:

public function find_all(object needle, sequence haystack, integer start=1) 
	integer kx = 0 
	while start with entry do 
		kx += 1 
		haystack[kx] = start 
		start += 1 
	entry 
		start = find(needle, haystack, start) 
	end while 
 
	haystack = remove( haystack, kx+1, length( haystack ) ) 
 
	return haystack 
end function 

Jeremy