[Emacs-ada-mode] [Emacs][ada-mode] ada-xref.el -- missing gnatls in PATH

[Pierre-Louis Escouflaire]

Hello,

Stephen Leake wrote:
> Pierre-Louis Escouflaire <pierre-louis.escouflaire at eurocontrol.int> writes:
> 
> 
>>We found a relatively drastic problem related to the 'ada-xref.el' 
>>script file that appears when you do NOT have 'gnatls' in your PATH.
>>
>><snip>
>>
>>Another solution (maybe wiser) would be to change `ada-find-executable' 
>>so that it raises an error when the executable has not been found. The 
>>one using it should then protect it using a `condition-case'.
> 
> 
> Yes, this is right way (you'd think people using Ada would not ignore
> errors!). Try this:
> 
> (defun ada-find-executable (exec-name)
>   "Find the full path to the executable file EXEC-NAME.
> If not found, throw an error.
> On Windows systems, this will properly handle .exe extension as well"
>   (let ((result (or (ada-find-file-in-dir exec-name exec-path)
>                     (ada-find-file-in-dir (concat exec-name ".exe") exec-path))))
>     (if result
>         result
>       (error "'%s' not found in path" exec-name))))
> 
> ada-find-executable is only used in ada-initialize-runtime-library, so
> this won't break anything else.
> 
> I don't think there's any point in attempting to handle the error in
> ada-initialize-runtime-library; if gnatls isn't found, nothing else
> will work either, because gnat won't be found.

This is perfectly correct... based on a developer's point of view.

However, I think that Emacs should start properly:
   . for users that only need to read Ada sources,
   . for users in a restrained environment,
   . for users not using the GNAT compiler and tools.

Thus, the 'ada-initialize-runtime-library' behavior might be to warn 
users that some features are not available because of one of the two 
last reasons.

An extension of this might be to enable/disable shortcuts, menu items, 
etc. whether or not the user is in a restrained environments or without 
the GNAT compiler and tools.
Another solution might be to raise an error saying that no tool allows 
the user to use these commands.

> Too late for 3.9; this will be in 4.00 (sometime).


Thanks for your concern.

Regards,
Pierre-Louis ESCOUFLAIRE

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