Re: [Caml-list] OCamldebug

[Tom Ridge <tom.j.ridge+list@googlemail.com>]

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My functors never hide anything, and always include the input module as a
submodule of the output module. So I hope that type equalities are as
maximally visible as they could be. But ocamldebug doesn't seem to get it :(



On 23 February 2017 at 17:02, Ivan Gotovchits <ivg@ieee.org> wrote:

> It matters whether in the signature of a module that is produced by the
> functor, the type of the key is still the same as the type of the key
> parameter. If it is not, then debugger cannot know, whether the output type
> is a key or not. Probably, if you add a sharing constraint between the
> functor parameter signature and the resulting module signature the debugger
> with capture it. Especially, if this would be an erasing signature
> (although it is not always possible), e.g.,
>
> module M = sig type key type t end
> module Make(Key : T) : M with type key = Key.t
>
>
> or
>
> module Make(Key : T) : M with type key := Key.t
>
>
>
> If these approaches do not work for you, then you can define a printer
> yourself in a separate module (that is loaded with `load_printer` command).
> In this printer you may apply a functor,
> and since functors are applicative in OCaml the debugger might be clever
> enough to pick this printer. It is not guaranteed, though, as the debugger
> is using lots of heuristics, and sometimes, they do fail.
>
>
> Best wishes,
> Ivan
>
>
>
> On Thu, Feb 23, 2017 at 11:49 AM, Tom Ridge <tom.j.ridge+list@googlemail.
> com> wrote:
>
>> Regarding `#install_printer`, can you explain more? The type
>> "Key_value_types.key" is equal to string (in this particular case).
>> However, this type is produced via module application, and so I cannot
>> construct a printer that can print values of type "Key_value_types.key"
>> before program execution (which seems to be required for #install_printer).
>>
>> Somehow I seem to want to tell ocamldebug that Key_value_types.key is in
>> fact equal to string. Or alternatively coerce kra (using Obj.magic) to
>> string type so that it can easily be printed by ocamldebug?
>>
>>
>>
>> On 23 February 2017 at 16:31, Ivan Gotovchits <ivg@ieee.org> wrote:
>>
>>> Probably it is an abstract type, that is represented as string. In any
>>> case you can use the `#install_printer` directive to enable printing any
>>> type. The argument
>>> is a function of type `t -> Format.formatter -> unit`, where `t` is a
>>> name of your type.
>>>
>>> On Thu, Feb 23, 2017 at 11:24 AM, Tom Ridge <
>>> tom.j.ridge+list@googlemail.com> wrote:
>>>
>>>> Dear All,
>>>>
>>>> I am debugging some code. For various reasons I have started to use
>>>> ocamldebug rather than printf.
>>>>
>>>> I should say that ocamldebug is excellent. Really excellent. Especially
>>>> the "backwards" stepping.
>>>>
>>>> However, sometimes I want to see the value of a particular variable. I
>>>> can use the "p" (print) command as:
>>>>
>>>> (ocd) p kra
>>>> kra: Key_value_types.key = <abstr>
>>>>
>>>> The problem is that I know that kra is a string. But ocamldebug only
>>>> shows <abstr>.
>>>>
>>>> Admittedly the code is functorized. But I have a feeling I should be
>>>> able to tweak something to get ocamldebug to print the value of kra.
>>>>
>>>> Any ideas?
>>>>
>>>> T
>>>>
>>>
>>>
>>
>

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