Re: [Gm2] lib problems

[Gaius Mulley]

"T.D. Telford" <address@hidden> writes:

> Hello,
>
> when I run a simple program (see below), I get the error
>
> gm2 -fiso power.mod
> /home/dtelford/opt/lib/gcc/x86_64-unknown-linux-gnu/4.1.2/gm2/pim/
> StrIO.def:60:1: error: unable to obtain the MIN value for type the ZType
> /home/dtelford/opt/lib/gcc/x86_64-unknown-linux-gnu/4.1.2/gm2/pim/
> StrIO.def:60:1: error: unable to obtain the MAX value for type the ZType
>
> I am running linux Fedora 15 X86_64.  I compiled gm2.
>
> Program (from algorithms and data structures):
>
> MODULE Power;
> (*compute decimal representation of negative powers of 2*)
>
> FROM STextIO  IMPORT WriteLn, WriteString;
>
> CONST N = 10;
> VAR i, k, r: INTEGER;
>     s : ARRAY[1..80] OF CHAR;
> d: ARRAY N OF CARDINAL;
> BEGIN
>   FOR k := 0 TO N-1 DO
>     WriteString("."); r := 0;
>     FOR i := 0 TO k-1 DO
>       r := 10*r + d[i]; d[i] := r DIV 2; r := r MOD 2;
>       s := "   " + CHR(d[i] + ORD("0"));
>       WriteString(s )
>     END ; (* for *)
>     d[k] := 5; WriteString("5"); WriteLn()
>   END (* for *)
> END Power.
>
> If I change the IMPORT to
> FROM StrIO  IMPORT WriteLn, WriteString;
>
> and compile with gm2 -fpim power.mod
>
> I get the same error.
>
> Ideas?
>
> Regards,
> Doug

Hi Doug,

yes you have a few errors in the code.  Your ARRAY declaration is
incorrect (it needs a type rather than a constant) and Modula-2 does not
allow programmers to add (non constant) strings with the operator +

Here is a corrected version (I think!)


MODULE Power;
(*compute decimal representation of negative powers of 2*)

FROM STextIO IMPORT WriteChar, WriteLn, WriteString;

CONST N = 10;
VAR
   i, k, r: INTEGER;
   s : ARRAY[0..80] OF CHAR;
   d: ARRAY [1..N] OF CARDINAL;
BEGIN
  FOR k := 0 TO N-1 DO
    WriteString("."); r := 0;
    FOR i := 0 TO k-1 DO
      r := 10*r + d[i]; d[i] := r DIV 2; r := r MOD 2;
      WriteChar(CHR(d[i] + ORD("0"))) ;
    END ; (* for *)
    d[k] := 5; WriteString("5"); WriteLn
  END (* for *)
END Power.



regards,
Gaius