Re: [Seed7-users] Compile-time errors

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

On Sat, 11 Jun 2022 07:04:00 +0200 Duke Normadin <dukeof...@gm...> wrote:
> s7 sandbox.sd7
> SEED7 INTERPRETER Version 5.1.632  Copyright (c) 1990-2022 Thomas
> Mertes *** sandbox.sd7(34):52: Match for {choice ::= "" } failed
>   end func;
> -----------^

Unfortunately this error message refers to the wrong line (34)
instead of the correct one (7). I will look into this issue.
The error message actually refers to the line

  var char: choice is "";

where you try to initialize a char variable with a string literal.
Char and string are different types so initializing a char with
a string is not possible.

The error message refers to the ::= operator that is never called
explizit. The ::= operator is used only by declaration statements
to initialize a variable or constant.
To correct this error use

  var char: choice is ' ';

instead. This initializes the char variable choice with the
char literal ' '.

> *** sandbox.sd7(34):32: Declaration of "choice" failed
>   end func;
> -----------^

This is a follow up error of the previous one.

> *** sandbox.sd7(19):52: Match for {choice getc } failed
>   getc(choice);

The function getc has a file a parameter and returns a char.
So getc cannot be used with a char parameter (choice).
I suggest to use

  choice := getc(IN);

instead. IN refers to the standard input file.

> *** sandbox.sd7(34):32: Declaration of "main" failed
>   end func;
> -----------^

This is a follow up error of all previous errors.

> The error msgs are not very informative IMHO.

I will try to look into that.

> You have very detailed language specs, but
> very few simple examples of everything possible. Newcomers to Seed7
> have to hut and search and dig for examples at the rosettacode
> site. That is /not/ good advocacy! It's too bad that this is the
> situation, because you might have a popular and productive language
> if there was a comprehensive tutorial to learn it from.

Thank you for the hint. I will try to improve the tutorial.

Your example uses also 'break' which is not needed in Seed7 case
statements.

Below is my improved version of your example:
---------- begin sandbox.sd7 ----------
$ include "seed7_05.s7i";
$ include "float.s7i";

const proc: main is func

local
  var char: choice is ' ';
  var integer: tempF is 0;
  var float: tempC is 0.0;

begin

  writeln("Temperature Conversion Utitlity");
  writeln("-------------------------------");
  writeln("a - Fahrenheit TO Celsius");
  writeln("b - Celsius TO Fahrenheit");
  writeln("q - To exit the program");
  writeln("Enter your choice");
  choice := getc(IN);

  case choice of
    when {'a', 'A'}:
      writeln("choice is " <& choice);
    when {'b', 'B'}:
      writeln("choice is " <& choice);
    when {'q','Q'}:
      writeln("Goodye ...");
    otherwise:
      writeln("Bad choice...");
  end case;

end func;
---------- end sandbox.sd7 ----------

I hope that helps.

Regards
Thomas