[Seed7-users] What's wrong?

[Thomas M. <tho...@gm...>]

On Fri, 14 Sep 2012 22:22:23 +0200, Renato Lenzi <re...@gm...> wrote:
> Here is a very simple code:
> 
> 
> $ include "seed7_05.s7i";
> $ include "char.s7i";
>     const proc: main is func
>       begin
>       end func;
> 
> and here is what compiler says (Win7 64):

There are some issues

  1. Only the first include command, the one which includes
     "seed7_05.s7i", needs a $ sign. Later include commands should not
     use a $ sign. The include commands without $ maintain, what was
     already included and therefore they do not include something twice.

  2. It is not necessary to include "char.s7i", since it is already
     included from "seed7_05.s7i".

  3. The construct

       func
       begin
         ...
       end func;

     assumes that there are one or more statements between 'begin' and
     'end'. Omitting the statement(s) between 'begin' and 'end' is like
     omitting a function parameter. For a missing function parameter you
     will get an error message. Likewise you get an error message when
     the statement(s) between 'begin' and 'end' are omitted. The empty
     statement is 'noop'. Just omitting a statement is not considered
     correct.

> HI INTERPRETER Version 4.5.9553  Copyright (c) 1990-2012 Thomas Mertes
> *** /d/seed7/lib/char.s7i(33):34: "char" declared twice
> const type: char           is subtype DISCRETE;
> -----------------------------------------------^

Because "char.s7i" is included twice the type 'char' is defined twice.

> *** /d/seed7/lib/char.s7i(129):34:  (in integer param) chr declared twice
> const func char: chr (in integer: number)                     is action
> "CHR_CHR
> ";
> --------------------------------------------------------------------------------
> --^

Because "char.s7i" is included twice the function 'chr' is defined twice.

> *** /d/seed7/lib/char.s7i(217):34: "EOF" declared twice
> const char: EOF is chr(-1);
> ---------------------------^

Because "char.s7i" is included twice the constant 'EOF' is defined twice.

> *** char02.sd7(5):30: Expression expected found "func"
>       end func;
> --------------^

This error is written, because there should be one or more statements
between 'begin' and 'end'. The other errors below are triggered by this
error message.

> *** char02.sd7(5):47: "end" expected found "func"
>       end func;
> --------------^
> *** char02.sd7(5):47: "func" expected found ";"
>       end func;
> ---------------^
> *** char02.sd7(5):46: ";" expected found "END OF FILE"
> 
> ^
> *** char02.sd7(3):51: Match for {func begin {end } } failed
>       begin
> 
> 
> may be it's too late but i don't understand....

No problem. Hopefully the explanation helps.

Currently

  const proc: main is func
    begin
    end func;

and

  if condition then
  end if;

are illegal. The legal versions of the examples above are

  const proc: main is func
    begin
      noop;
    end func;

and

  if condition then
    noop;
  end if;

Maybe there should be versions of statements, where statement parameters
can be omitted.


Regards,
Thomas Mertes