Re: Procedure Const parameter?

[john o goyo]

Hung Hung,

I concur with the suggestion from Andreas.  (Copies may found online.)

I have been a professional programmer for over 35y (mostly in procedural 
languages, such as C, but also others).  When my job required learning a 
new language, I found it most useful to first work through the 
definitive book on the language.  I never found it useful to try to 
translate code from another language first.  Every language has its own 
philosophy and idioms.  I strongly suggest immersion first.  It may seem 
time-consuming but it pays well at a later stage.

Sincerely,
john

On 24/03/2020 14:29, Fischlin Andreas wrote:
> Dear Hung Hung,
>
> Given the many questions you ask, I highly recommend to you to read
>
> Programing in Modula-2 by Niklaus Wirth. Springer. I recommend ed. 3.
>
> This is anyway a very good and enjoyable read and should help you to understand 
> M2 quickly, answer all your questions efficiently, and even introduce you to 
> the spirit of Modula-2 and the structured programing it supports.
>
> Regards, Andreas
>
> ETH Zurich, Prof. em. Dr. Andreas Fischlin, IPCC Vice-Chair WGII, Systems 
> Ecology, CHN E 24, Universitaetstrasse 16, CH-8092 Zurich, SWITZERLAND
> Tel: +41 44 633-6090   Mobile: +41 79 595-4050   Mail: address@hidden
> www.sysecol.ethz.ch/people/andreas.fischlin.html
>
> > On 24 Mar 2020, at 19:15, Gaius Mulley<address@hidden>  wrote:
> >
> > Hưng Hưng<address@hidden>  writes:
> >
> > > Free Pascal has this: procedure test(const x: pchar);
> > >
> > > What is the equivalent in gm2?
> > >
> > > I want a const pointer. e.g:
> > >
> > > type test = pointer to integer;
> > > procedure testit(const x: test);
> > >
> > > I need it to be able to complete the translation of the C header to
> > > gm2.
> > Hi,
> >
> > there is no const pointer in Modula-2
> >
> > you can either use:
> >
> > example.def
> >
> > DEFINITION MODULE FOR "C" example ;
> >
> > TYPE
> >    ptr = POINTER TO INTEGER ;
> >
> > PROCEDURE foo (a: ptr) ;
> > PROCEDURE bar (VAR a: ptr) ;
> >
> > END example.
> >
> > fortunately you can either state this as const or without const in your
> > C file
> >
> > example.c
> >
> > void example_foo (const int *a);    /* add/remove const as suits.  */
> > void example_foo (int **a);    /* add/remove const as suits.  */
> >
> > etc
> >
> > regards,
> > Gaius