Re: Strings

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

Your problem is that Ada.Strings.Bounded.Generic_Bounded_Length
is a generic _package_, not a type.

An instantiation of that _package_ exports a type Bounded_String.

So, if in your original example, you substitute
package Bounded_80 is new ...
for type Bounded_80 is new ...
everything will work as expected.


"Jef Kelmo" <jlk@vdu.org> wrote in message news:3A42418F.ACCD532A@vdu.org...
> Hello,
>
>     This is not a homework question. In 5 months, I will begin work that
> uses Ada and am trying to become familiar with it now. But I am having a
> problem with how to use strings; a problem that seems common across a
> number of languages, including C++ and Java.
>
>     I entered the following...
>
> --------------------------------------------------------------------------
--------------------------------
>
> with Ada.Text_IO;
> with Ada.Strings.Bounded;
>
> procedure My_Strings is
>     type Bounded_80 is new
> Ada.Strings.Bounded.Generic_Bounded_Length(80);
>
>     a1 : Bounded_80.Bounded_String := Bounded_80.To_Bounded_String("Some
> Text");
>
> begin
>     Ada.Text_IO.Put(Bounded_80.To_String(a1));
>     Ada.Text_IO.New_Line;
>
> end My_Strings;
> --------------------------------------------------------------------------
--------------------------------
>
>  ...and when I compile, I get the following...
>
> gcc -c my_strings.adb
> my_strings.adb:5:47: subtype mark required in this context
> my_strings.adb:5:70: incorrect constraint for this kind of type
> my_strings.adb:7:10: invalid prefix in selected component "Bounded_80"
> my_strings.adb:7:39: invalid prefix in selected component "Bounded_80"
> my_strings.adb:12:21: invalid prefix in selected component "Bounded_80"
> gnatmake: "my_strings.adb" compilation error
>
>
>     So my first guess is to change...
>
>     type Bounded_80 is new
> Ada.Strings.Bounded.Generic_Bounded_Length(80);
>
>     ...to...
>
>     subtype Bounded_80 is new
> Ada.Strings.Bounded.Generic_Bounded_Length(80);
>
>     ...in which case I get...
>
> gcc -c my_strings.adb
> my_strings.adb:5:27: "new" ignored (only allowed in type declaration)
> gnatmake: "my_strings.adb" compilation error
>
>     ...so I remove the "new" and get...
>
> gcc -c my_strings.adb
> my_strings.adb:5:46: subtype mark required in this context
> my_strings.adb:5:69: incorrect constraint for this kind of type
> my_strings.adb:7:10: invalid prefix in selected component "Bounded_80"
> my_strings.adb:7:39: invalid prefix in selected component "Bounded_80"
> my_strings.adb:12:21: invalid prefix in selected component "Bounded_80"
> gnatmake: "my_strings.adb" compilation error
>
>     Is it obvious by now that I don't know what I am doing? I have a
> copy of Ada as a 2d Language and I looked up the Ada Reference on
> adapower.com, but everything is too vague and anything I try does not
> work.
>
>     I just want a usable string. How would I change the above code to do
> this? And could someone please point me to a site that gives actual,
> concrete examples of simple string use?
>
>     Thanks.
>
> James
>
>