array bounds must be constant - Printable Version

array bounds must be constant - Printable Version

+- Forum (https://www.boriel.com/forum)
+-- Forum: Compilers and Computer Languages (https://www.boriel.com/forum/forumdisplay.php?fid=12)
+--- Forum: ZX Basic Compiler (https://www.boriel.com/forum/forumdisplay.php?fid=11)
+---- Forum: Help & Support (https://www.boriel.com/forum/forumdisplay.php?fid=16)
+---- Thread: array bounds must be constant (/showthread.php?tid=314)

array bounds must be constant - slenkar - 02-22-2011

How do I create an array with an integer instead of a literal number?

I want to do this:

Code:
DIM personX (numPersons) as ubyte

DIM personY (numPersons) as ubyte

DIM personHealth (numPersons) as ubyte

DIM personWeapon (numPersons) as ubyte

instead of:

Code:
DIM personX (6) as ubyte

DIM personY (6) as ubyte

DIM personHealth (6) as ubyte

DIM personWeapon (6) as ubyte

just in case I decide to change my mind about the number of persons

Re: array bounds must be constant - boriel - 02-22-2011

Unfortunately this is not (yet) supported. What you're asking is a DYNAMIC ARRAY. Sad

This is a feature planned for 1.2.8 (or higher). Dynamic array are a bit trickier, slower and might take a little more memory, but on the other hand are more powerful and allow redimension during runtime. Meanwhile, you can create an array with a MAXPERSONS size (e.g. 20), and use a variable to store the real number of persons:

Code:
CONST MaxPersons As Ubyte  = 20 

DIM a(MaxPersons) As Ubyte

LET numPersons = 10 : REM number of persons by now...

FOR i = 1 TO numPersons

    LET a(i) = RND * 10

NEXT i

And yes, you will allocate 10 unused positions.
DYNAMIC Arrays are planned for the next release, please, be patient.

Re: array bounds must be constant - slenkar - 02-22-2011

ah const, I didnt know we had that type thanks Big Grin

Re: array bounds must be constant - boriel - 02-22-2011

slenkar Wrote:ah const, I didnt know we had that type thanks

You can also use #define (like a C preprocessor):

Code:
#define MaxPersons 20

In fact, what's new in 1.2.7 is the complete new preprocessor, which allow powerful macros to be used as inline functions

Code:
#define MyFunc(x, y)  \

    PRINT x * y + 1; \

    PRINT " is the result"

MyFunc(3, 2)

The above program is literally converted to

Code:
PRINT 3 * 2 + 1;

PRINT " is the result"

And even much more complex examples!

Re: array bounds must be constant - slenkar - 02-22-2011

inline functions are cool too Wink

Re: array bounds must be constant - compiuter - 02-23-2011

Hi, Can I use #define functions in fastcalls or subs?

Re: array bounds must be constant - boriel - 02-23-2011

compiuter Wrote:Hi, Can I use #define functions in fastcalls or subs?

Yes; #define are just MACROS. Wherever you invoke them, they will be *replaced* with its definition.

Re: array bounds must be constant - compiuter - 02-26-2011

macros functions created with #define can contain embebed asm or only basic?

Re: array bounds must be constant - boriel - 02-26-2011

compiuter Wrote:macros functions created with #define can contain embebed asm or only basic?

Whatever! Of course, if you must use ASM...END ASM to use macros. Remember also to end each line with \ or _ character (line break continue), to tell the compiler those lines are macro ones:

Code:
DIM a As Ubyte = 1

#define MyMacro  \

    PRINT a; " MACRO START" \

    ASM \

    ld hl, _a \

    inc (hl) \

    END ASM \

    PRINT a; " MACRO END"

PRINT "HELLO WORLD"

MyMacro

Notice line continuations "\". You can use "_" instead.
You can think of macros like inline SUBs.

Update: errr... :oops: Just discovered the ASM inside the macro wasn't being correctly supported!. This bug has been fixed and now it works. Please download r2109

Re: array bounds must be constant - compiuter - 03-08-2011

Code:
#define MyFunc(x, y)  \

    PRINT x * y + 1; \

    PRINT " is the result"

MyFunc(3, 2)

I was testing and I can not compile macros with parameters. Sad

Re: array bounds must be constant - boriel - 03-08-2011

It works ok to me. :?:
Which compiler version are you using? Download 1.2.7 or the latest devel, and try again...

Re: array bounds must be constant - compiuter - 03-08-2011

Perhaps the version. I´ll take a look.