Comparison Operators for Strings

Comparison Operators for Strings

[Rick]

How do the comparison operators for Strings (Fixed-length, Unbounded,
whatever) actually work?  I am using Unbounded_String at the moment
and in the LRM I find:

83 Each of the functions "=", "<", ">", "<=", and ">=" returns the
same result as the corresponding String operation applied to the
String values given or represented by Left and Right.

I have checked LRM 2.6, 3.6.3, and A.4 to A.4.8 and I cannot find a
result for a corresponding String operation.

Where should I be looking?

--------------------------------------------
Rick Duley
North Perth,
Western Australia
http://rickduley.webs.com
--------------------------------------------

Re: Comparison Operators for Strings

[Steve D]

"Rick" <rickduley@gmail.com> wrote in message 
news:59ccf9ff-86ea-4179-8be3-a7f99218eeb5@q40g2000prh.googlegroups.com...
> How do the comparison operators for Strings (Fixed-length, Unbounded,
> whatever) actually work?  I am using Unbounded_String at the moment
> and in the LRM I find:
>
> 83 Each of the functions "=", "<", ">", "<=", and ">=" returns the
> same result as the corresponding String operation applied to the
> String values given or represented by Left and Right.
>
> I have checked LRM 2.6, 3.6.3, and A.4 to A.4.8 and I cannot find a
> result for a corresponding String operation.
>
> Where should I be looking?
>

LRM 4.5.2 Relational Operators an Membership tests
Paragraph (18)

The type "String" is nothing special and is defined in System:

type String is array(Positive range <>) of Character;
   pragma Pack(String);

You compare strings the same way as you can any other one dimensional array 
as described in 4.5.2(18)

Regards,
Steve

> --------------------------------------------
> Rick Duley
> North Perth,
> Western Australia
> http://rickduley.webs.com
> --------------------------------------------

Re: Comparison Operators for Strings

[Adam Beneschan]

On Aug 25, 6:37 pm, "Steve D" <nospam_steve...@comcast.net> wrote:
> "Rick" <rickdu...@gmail.com> wrote in message
>
> news:59ccf9ff-86ea-4179-8be3-a7f99218eeb5@q40g2000prh.googlegroups.com...
>
> > How do the comparison operators for Strings (Fixed-length, Unbounded,
> > whatever) actually work?  I am using Unbounded_String at the moment
> > and in the LRM I find:
>
> > 83 Each of the functions "=", "<", ">", "<=", and ">=" returns the
> > same result as the corresponding String operation applied to the
> > String values given or represented by Left and Right.
>
> > I have checked LRM 2.6, 3.6.3, and A.4 to A.4.8 and I cannot find a
> > result for a corresponding String operation.
>
> > Where should I be looking?
>
> LRM 4.5.2 Relational Operators an Membership tests
> Paragraph (18)
>
> The type "String" is nothing special and is defined in System:
>
> type String is array(Positive range <>) of Character;
>    pragma Pack(String);
>
> You compare strings the same way as you can any other one dimensional array
> as described in 4.5.2(18)

Well, not *any* other one-dimensional array; the ordering operations
("<", "<=", ">", ">=") are defined only for one-dimensional arrays of
a *discrete* type (i.e. integer or enumeration; Character is an
enumeration type).  4.5.2(18) only applies to "=", by the way.  For
ordering operators, see 4.5.2(8-9) and 4.5.2(26).

                                     -- Adam

Re: Comparison Operators for Strings

[rickduley]

Thanks fellas.  That's solved the problem but ...

This is purely rhetorical, why doesn't the LRM say to look there?
It'd save people like me a bit of time :)

--------------------------------------------
Rick Duley
North Perth,
Western Australia
--------------------------------------------