1. A C to Euphoria Question: struct
Dear Euphorians,
I saw an interesting piece of code the other day in
C, and was wondering how one would do the same thing
in Euphoria. (I think Qbasic has something like it too
with TYPE) Here's the code :
struct {
int x, y;
char Direction;
char MovePixels;
char CurrFrame;
char NumFrames;
char FrameRate;
char FrameCount;
unsigned char *data[20];
} MainChar;
I think that's about it. (just a small bit of C -- don't want to be
a burden or anything) I haven't seen anything looking like :
"MainChar.Direction = ...." in Euphoria before. If anyone could clear
this up for me, it would be much appreciated. Thank you very much.
Chris Cox
cox.family at sk.sympatico.ca
2. Re: A C to Euphoria Question: struct
Unfortunately, Euphoria doesn't support types or structs. You can implement
the same thing using sequences, though:
constant MainChar_x =3D 1, MainChar_y =3D 2, MainChar_Direction =3D 3,
MainChar_MovePixels =3D 4, MainChar_CurrFrame =3D 5, MainChar_NumFrames =3D
6, MainChar_FrameRate =3D 7, MainChar_FrameCount =3D 8, MainChar_data =3D 9
I am working on a pre-processor for Euphoria that will allow for pointers
and structures, but it isn't finished yet. You can get the current version
at http://members.tripod.com/~JJProg/epp.html.
Also, in C, * means pointer so data is an array of 20 pointers to
characters. Euphoria doesn't support pointers either, though you can get
pointer.e from the Euphoria web site (http://members.aol.com/fileseu/)
which allows you to create "pointers" in Euphoria. Sometimes, pointers in C
are used for dynamic arrays (which C, unlike Euphoria, doesn't support). In
this case, you could do the same thing using sequences. If you need to
check the sequences to make sure they are in the right format, you could
use something like this:
type OneD(object s)
if not sequence(s) then
return 0
end if
for i =3D 1 to length(s) do
if sequence(s[i]) then
return 0
end if
end for
return 1
end type
type MainChar(object s)
if not sequence(s) then
return 0
end if
if length(s) !=3D 9 then
return 0
end if
for i =3D 1 to 8 do
if not integer(s[i]) then
return 0
end if
end for
if length(s[9]) !=3D 20 then
return 0
end if
for i =3D 1 to 20 do
if not OneD(s[i]) then -- Replace OneD with Pointer if you are
using
pointers
return 0
end if
end for
return 1
end type
MainChar c
c =3D
""}}
-- Or (if you are using pointers)
c =3D {0,0,0,0,0,0,0,0,{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}}
Jeffrey Fielding
JJProg at cyberbury.net
3. Re: A C to Euphoria Question: struct
Chris Cox wondered about structures in Euphoria:
>struct {
> int x, y;
> char Direction;
> char MovePixels;
> char CurrFrame;
> char NumFrames;
> char FrameRate;
> char FrameCount;
> unsigned char *data[20];
>} MainChar;
The equivalent in Euphoria might look something like:
-- define the indexes
constant
X = 1,
Y = 2,
Direction = 3,
MovePixels = 4,
CurrFrame = 5,
NumFrames = 6,
FrameRate = 7,
FrameCount = 8,
Data = 9,
-- default structure
MainChar = { 1, 1, 0, 0, 0, 0, 0, 0, "" }
You can then create objects of that type with:
sequence newThing
newThing = MainChar
newThing[X] = 12
newThing[Y] = 80
newThing[Direction] = -2
newThing[MovePixels] = 7
newThing[CurrFrame] = 12
newThing[NumFrames] = 32,
newThing[FrameRate] = 24
newThing[FrameCount = 8
newThing[Data] = "text"
or more obscurely:
newThing = { 12, 80, -2, 7, 12, 32, 24, 8, "text" }
If you need *real* C structs (like for passing a structure to a DLL) you can
find tools for that in my Win32Lib. But it doesn't sound like you are aiming
for anything like that.
Hope this helps!
-- David Cuny
