Re: Commercial C To Ada 95 compiler

[Darren New <dnew@san.rr.com>]

Jim Rogers wrote:
> One simple example is indexing past the end of an array.
> C compilers simply will not catch this problem. Ada compilers will.

True, assuming it's sufficiently obvious. I would think there might be a lot
of weird C-ish stuff that Ada would have trouble doing, like malloc'ing an
array of floats and then casting it to a (char *) and filling it in with
some pattern.
 
> On the whole, direct translation may not be possible. C uses
> implicit conversion between integer and floating point types.
> Ada provides no such implicit conversion. You will at least need
> to make all implicit C conversions explicit in Ada.

Well, I would imagine that the translator could do this, yes?

C:
  f = i;
Ada
  f := Float (i);



> Another incompatibility is trying to reference the control
> variable in a "for" loop outside the scope of the "for" loop.
> This is impossible in Ada and not uncommon in C. The C compiler
> will allow this. The Ada compiler will not.

Well, if your translator translates C for loops that have references to the
index variable outside the for loop into Ada for loops, it'll be a problem.
They'd have to translate it to the corresponding while loop.
 
I guess if you're going to be strict enough about the word "direct
translation" to mean that a C for loop can't translate to an Ada while loop,
what you say would be true. I don't think that's what's generally meant by
"direct translation".

I think there would be more problematic constructs, tho, like static
variables (inside and/or outside of functions), pointers cast to different
types, and so on. 

-- 
Darren New 
San Diego, CA, USA (PST). Cryptokeys on demand.
** http://home.san.rr.com/dnew/DNResume.html **
** http://images.fbrtech.com/dnew/ **

     My brain needs a "back" button so I can
         remember where I left my coffee mug.