* student needs help for his project
@ 1999-01-11 0:00 Bug
1999-01-11 0:00 ` David C. Hoos
0 siblings, 1 reply; 2+ messages in thread
From: Bug @ 1999-01-11 0:00 UTC (permalink / raw)
Hi i'd like to ask you a question.
I need to create a proggy like excel (very simplified of course)
I've got an array of cells and each cells contain infos such as -string
or expression to be evaluated
-cords of the cell in the array
-a pointer to a list of child cells (that depends on the content of the
parent one)
Ok are you following me? yep i think (sorry for the bad english but i'm
french... :) )
I've got some packages to do this but two of them are giving me white
hair
-the one that define the object "cell"
-the one that define the object "list" (a list is a
chained list if the name is the same in french and in english)
Ok then, the list contains the pointers towards the child cells so in
the package list.ads, i need to refer to the package cells.ads, but as i
need list object i the definition of a cell i need to refer to the
package list.ads...it's like the snake that bit his tail...
Of course the compiler reject the thing..
SO what i wanted to know is wether i need simply to think agin my
construction or if a solution exists.
Here is part of the code :
*********************************************
with list,...;
use list,.....;
package cells is
..........
type cell is record
content : ptr_content; -- ptr content is a record of
two access types defined somewhere not important
pos : cords; -- line and row
child_list : chained_list; -- defined in the
list.ads
end record;
type ptr_cell is access cell;
..........
end cells;
*****************************************
with cells;
use cells;
package list is
....................
type ring;
type ptr_ring is access ring;
type ring is record
information : ptr_cell;
link : ptr_ring;
end record;
type chained_list is record
lenght:natural;
firts_case:ptr_ring;
end record;
.............
end list;
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: student needs help for his project
1999-01-11 0:00 student needs help for his project Bug
@ 1999-01-11 0:00 ` David C. Hoos
0 siblings, 0 replies; 2+ messages in thread
From: David C. Hoos @ 1999-01-11 0:00 UTC (permalink / raw)
Bug wrote in message <369A311A.156DA9A1@ensica.fr>...
<snip>
>a list is a
>chained list if the name is the same in french and in english)
>
Well .. in English we usually say "linked list," but everyone should
understand you.
<snip>
>SO what i wanted to know is wether i need simply to think agin my
>construction or if a solution exists.
You cannot have a circular package dependency in Ada -- although C doesn't
care about such things.
You could simply declare cell in the list package. Then you would do a
partial declaration of type cell, and defer its fill declaration, just as
you did for the type ring.
David C. Hoos, Sr.
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