Re: [Ada-mode-users] wrong indentation of some complex expressions

[Stephen Leake]

Ludovic Brenta <address@hidden> writes:

> In the example below, the line "/= A" is incorrectly indented relative
> to the beginning of the entire expression instead of the sub-
> expression.  I think it should be indented by ada-indent relative to B,
> which starts the sub-expression:
>
> procedure Andthen is
>   A : Boolean;
>   B : Boolean;
> begin
>   if A
>     and then B
>     /= A
> -- should be:
> --             /= A -- indented by ada-indent relative to B

This is related to your post about leading parens; apparently it is all
hanging indents, not just parens.

If I add parens, it does what you want:

   if A
     and then (B
                 /= A)
   then
   end if;

This was done mainly for aggregates and argument lists; it makes less
sense (to me ;) here.

Without the paren, "/= A" is indented relative to "if", because the
first "A" is the start of the expression, and "/= A" is indented
relative to that line.

The indentation engine does not keep track of sub-expressions unless
they are in parens.

So there is no easy way to fix this; we'd have to add a
"sub_expression_start", and mark those in the grammar. The grammar is
structured that way, so that's not too hard. That would slow down the
parser some (parse time is dominated by set-text-property). Then we'd
have to add rules for that.

Ada mode 4.0 does not do what you want (just tested in emacs -Q); does
some other editor?

-- 
-- Stephe