Re: Permutation generator in ada library

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 14-10-03 14:00 , Brian Drummond wrote:
> On Thu, 02 Oct 2014 21:01:57 -0700, Stribor40 wrote:
> 
>> in the post above there is package that generates these permutations....
>>
>> I have saved 3 files....in same order as the files are in posting
>> Generic_Perm.ads  Generic_Perm.adb   Print_Perms.adb
>>
>> when i try to compile....gnatmake Print_Perms.adb I get error...
>>
>> Generic_Perm.adb:1:14: file "generic_perm.ads" not found gnatmake:
>> "Generic_Perm.adb" compilation error
>>
>> What am i doing wrong?
> 
> Gnat for some reason lower-cases the filenames when generating them from 
> the package names.

The reason is IMO clear: package names are case-insensitive in Ada, so
the context clauses "with PKG" and "with Pkg" refer to the same package.
If you want to generate case-sensitive file names from package names,
the case distinction must be suppressed, so the reasonable choices are
all-upper-case or all-lower-case, with the lower-case alternative
clearly preferable as few people keep their Caps-Lock on.

> On Linux, the filenames Generic_Perm.ads and generic_perm.ads actually 
> refer to different files

Yes, but the weird thing is that the error message Stribor40 quotes
shows that GNAT is compiling the generic package body in
Generic_Perm.adb, but cannot find the declaration in generic_perm.ads.
Oh well, I understood it is working with lower-case names, so...

(OMG, fiddling with this question made me realise that Mac OS-X uses, by
default, case-insensitive file names, although it is otherwise
Unix-type. Funny things happen, for example the command "mv -i aaa AAA"
asks me if I want to "overwrite AAA? (y/n [n])" - but there is no AAA...)

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
      .      @       .