Richard Jones wrote : > Possible workarounds:
> ...
> * Surround every possible array index with a try ... with expression
> like this:
>
> try
> (* code which accesses the array *)
> with
> Invalid_argument "index out of bounds" ->
assert false
>
> The "assert false" will print the line and character number
of the
> assertion.
Dear Richard,
I agree with you that this is feasible whenever array
elements feature in the right hand side of assignments. But how about the
left hand sides of assignments ? E.g. the following obviously is not correct
OCaml syntax.
let
a = Array.init 2 0;;
try
a.(2) <- 1
with
Invalid_argument "index out of bounds"
-> assert false;;
let
h = try a.(2)
with
Invalid_argument "index out of bounds"
-> assert false in
h <- 1;;
Regards,
=Andries
------------------------------------------------------------------------
Dr. Ir. Andries P. Hekstra
Philips Research
High Tech Campus 27 (WL-1-4.15)
5656 AG Eindhoven
Tel./Fax/Secr. +31 40 27 42048/42566/44051
* Good open source break software for computer users : http://www.workrave.org
Richard Jones <rich@annexia.org>
06-03-2006 12:14
To
Andries Hekstra/EHV/RESEARCH/PHILIPS@PHILIPS
cc
caml-list@yquem.inria.fr
Subject
Re: [Caml-list] Line number for index
out of bounds
Classification
On Mon, Mar 06, 2006 at 11:44:31AM +0100, Andries
Hekstra wrote:
> Invalid_argument("index out of bounds")
[...]
> Of course, I am very curious in which line number of the program this
> exception occurs.
> Is there any way to get hold of this line number?
This is a real problem with OCaml - it's impossible to get stack
traces of where an exception happens with native code. I'm assuming
you're using native code. I commonly have cases where a program dies
with "exception: Not_found" because I forgot to enclose some
List.find
with an appropriate try ... with clause, or made some wrong
assumption. Tracking these down is time-consuming.
Possible workarounds:
* Use bytecode, and before running the program set the environment
variable OCAMLRUNPARAM=b which will print a stack trace.
* Surround every possible array index with a try ... with expression
like this:
try
(* code which accesses the array *)
with
Invalid_argument "index out of bounds" -> assert
false
The "assert false" will print the line and character number of
the
assertion.
* Hack ocamlopt to be able to print exceptions properly :-)
Rich.
--
Richard Jones, CTO Merjis Ltd.
Merjis - web marketing and technology - http://merjis.com
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