1. newcomer problem
To all Euphoria enthusiasts:
I have a multi-dimensional array, array[x][y].
This array is now little, but could grow up to some Mbyte.
During debug, when I want to know the content of a cell (example: array[3=
70][41]), the answer is: "NOT DEFINED AT THIS POINT". I can see only the=
first elements in the array by typing "array".
Is there a solution to overcome this?
2. Re: newcomer problem
- Posted by Ralf Nieuwenhuijsen <nieuwen at XS4ALL.NL>
Nov 14, 1998
-
Last edited Nov 15, 1998
>To all Euphoria enthusiasts:
>I have a multi-dimensional array, array[x][y].
>This array is now little, but could grow up to some Mbyte.
>During debug, when I want to know the content of a cell (example:
array[370][41]), the answer is: "NOT DEFINED AT THIS POINT". I can see only
the first elements in the array by typing "array".
>Is there a solution to overcome this?
First of all, the actual size is dynamic, once a new cell is *initialized*
you can use it.
sequence my_array
my_array = {{}} -- 2D array
Now you want to set cell [370][41] you need to specific cells [1..369].
To simulate basic arrays, you could do this:
constant CELLS = 370, ROWS = 41
my_array = repeat (repeat(0,CELLS),ROWS)
All values are now initialized to 0 (like in basic)
You can now set the value of a cell:
my_array[370][41] = "Hello!"
However, to set cell 41, you need to ADD it.
my_array[370] = append(my_array[370], "This goes into cell 42")
After that you could set it to another value:
my_arra[370][42] = "This is the 42th row"
To add another row with 41 cells do this:
my_array = append(my_array, repeat (0, CELLS))
All cells are initialized to 0 (like in basic).
You could also have a new row that is a copy of an other row:
my_array = append(my_array, my_array[1])
Now the first row, is copied and add to the array at the end.
This is how sequences work. They are dynamic, but they can *not* contain
uninitialized values. They can be un-initialized:
sequence s
-- s is not yet initialized
s = {}
There is no way to add an un-initialized *element* (Euphoric term: same as
cell) to the sequence. You can only add *values* not just room for values.
The declaration and storage occupation is all handled by the interpreter
dynamically. Even though you have 400 by 400 array, it may well be much
different in memory, if the interpreter can figure it can "cheat".
For example:
s = repeat ("Euphoria", 10)
S is now a sequence, containing 10 sequences contain the atoms for each
character in "Euphoria". Its like:
{ "Euphoria",
"Euphoria",
"Euphoria"
.. etc.. (10 times)
}
You would think it would have the sequence/string "Euphoria" in memory 10
times, though this is an example where it cheats, and only keeps one
instance of "Euphoria" in memory and points to it 10 times. It can cheat,
because the end-programmer (you and me) has no control over storage at all.
We can't add room for data storage, only data itself, where Euphoria handles
all the storing issues.
Ralf
3. Re: newcomer problem
On Sat, 14 Nov 1998 20:50:57 +0100, Ralf Nieuwenhuijsen <nieuwen at XS4ALL.NL>
wrote:
>>To all Euphoria enthusiasts:
>>I have a multi-dimensional array, array[x][y].
>>This array is now little, but could grow up to some Mbyte.
>>During debug, when I want to know the content of a cell (example:
>array[370][41]), the answer is: "NOT DEFINED AT THIS POINT". I can see only
>the first elements in the array by typing "array".
>>Is there a solution to overcome this?
>
>
>First of all, the actual size is dynamic, once a new cell is *initialized*
>you can use it.
>
Correct. But the message "not defined at this point" is
Euphoria's response (in the trace mode) to *any* reference
to an element of a sequence:
name = "Irv"
? name will print "Irv", whereas (in the debugger) ? name[1] will
say "not defined at this point".
What it really is saying is: Euphoria can't do that, even though
it can easily reference the same array elements programmatically.
Try this:
with trace
sequence array
array = repeat(repeat({},100),400)
trace(1)
array[371][41] = 49
? array[371][41]
-- look at array in the trace mode.
Other than sprinkling print statements thru the code, you can use
the type () function to track changes to an element of an array.
Irv
4. Re: newcomer problem
Franco Marangoni wrote:
> To all Euphoria enthusiasts:
> I have a multi-dimensional array, array[x][y].
> This array is now little, but could grow up to some Mbyte.
> During debug, when I want to know the content of a cell (example:
> array[370][41]), the answer is: "NOT DEFINED AT THIS POINT". I can see only the
> first elements in the array by typing "array".
> Is there a solution to overcome this?
If you want to see the contents only at certain points, you can put in a print
statement:
? array[370][41]
A better (neater) way is to display the item each time there is an assignment
to it:
This is easy using the Euphoria "type", as there is only 1 line of code to
change when
you are finished debugging (instead of numerous "print" statements scatterd
thru your
program!)
I use:
type debug_array (object x)
position(1,1) puts(1,' ') -- blank out previous
contents
position(1,1) ? x[370][41] -- show the area in
question
-- you could insert a pause or delay here if things are changing much too
fast.
return 1
end type
now, define your array as:
debug_array my_array
rather than
sequence array
change it back to
sequence array
when you're finished debugging.
Regards,
Irv
