Re: Formatted IO - Fortran style or similar.

[Ian Clifton <ian.clifton@chem.ox.ac.uk>]

Mark Murray <w.h.oami@example.com> writes:

> Is there anyting in the Ada Standard Library (or the language itself)
> that acts /in loco/ Fortran's formatted I/O or C's printf()/scanf()?

> I know these can be written as required, and I know that there are ways
> to call C's printf()/scanf() functions from Ada, but I'm interested to
> see if there is not already something "in the box". Yes, I'm aware of
> the formatting capabilities of put()/get(), but that's not quite what
> I'm wondering about.

I’m not quite sure what facilities you’re after—I don’t know C’s
printf()/scanf(), but presumably they are quite different from Fortran’s
format control—but I suspect the answer is going to be “Ada’s approach
is different” (see below).

> I could have sworn I saw a PL/1-style "picture" version of this, but I'm
> coming round to believing that this was "customer code", not standard
> library.

Here, you could be thinking about “Edited Output for Decimal types”,
described in the ARM Appendix F. 

> PS: Is it really the case that put(some_integer,16) will _always_
> print the '16#9999#' format, and that there is on way _in_the_
> _standard_library_ of *not* getting the '16#.....#' wrapper?
> Yes, I know there are ways you can get rid of it (eg with a slice), or
> by "rolling your own" - alternatives aren't my question here :-).

I believe Ada’s approach is to specify the results of
put(some_integer,16) sufficiently carefully that you can do such
post‐processing with the provided string manipulation packages and be
confident of the final result. In other words, what you are trying to
avoid ARE the language’s facilities for doing this sort of thing. I ought
to mention in passing, the Ada.Text_IO packages are a little
controversial, many dislike them, but I believe they are under‐rated.

-- 
Ian ◎