Re: [MirageOS-devel] Camlp4 Stack_overflow

[Andrà NÃss <andre.naess@xxxxxxxxx>]

The idea was to keep the application as simple as possible by moving
all processing to compile time. It would avoid the startup cost of
reading all the entries and thus make for simpler deployment, but I
realise I may be taking it a bit too far :)

Using the crunch approach is probably more reasonable. I guess I just
figured that my approach was even simpler since I wouldn't have to
understand the crunch approach and how to read data back in the
application.

On Thu, May 8, 2014 at 12:38 AM, Anil Madhavapeddy <anil@xxxxxxxxxx> wrote:
> To address the camlp4 problem, you can use the _tags file to mark just
> the one source file as not passing through camlp4 (via a '-' somewhere
> to remove the tag -- will need to look up the details in the manual).
>
> The easiest way to solve your problem would be just to have a crunched
> file containing the information in CSV or S-expression format, and then
> reading from it at application startup time to initialize your array.
>
> The 'crunch' mode would compile all this into a standalone kernel, or
> in Unix mode would be a filesystem passthrough for easier development.
> Any reason you want it to be a 'hand written' OCaml file?
>
> -anil
>
> On 7 May 2014, at 14:06, Andrà NÃss <andre.naess@xxxxxxxxx> wrote:
>
>> I've rewritten the generated code so that it creates an array and then
>> assigns to indexes of the array, batching the assignments using
>> multiple let () =
>>
>> Compilation speed is a problem, and it still falls over at 50K entries.
>>
>> I suppose I could somehow write the data to an image and read it back
>> in at application startup, but I think I actually like my current
>> approach. All of the work is done at compilation time. The rows are
>> written in sorted order so a simple binary search can be used. The
>> resulting application is entirely single-purposed.
>>
>> Any ideas for other ways to do this? Bypass the compiler and "compile"
>> the data myself? Does there exist tools to do something like that?
>>
>> On Wed, May 7, 2014 at 1:40 PM, Andrà NÃss <andre.naess@xxxxxxxxx> wrote:
>>> Hi
>>>
>>> I'm trying something that might be a bit silly but it's just intended
>>> as an internal demo of Mirage to my team. I'm writing a tiny HTTP
>>> based application whose only purpose is to allow you to search a phone
>>> book.
>>>
>>> I've based my approach on the approach you've used for static websites
>>> using crunch where you compile the web pages into the executable. In
>>> my case that means I take the list of name and number pairs and stuff
>>> them into an array. So part of my config.ml file emits a single Pb.ml
>>> file which contains an array declaration like this:
>>>
>>> let db = [|("Aaron Jaksic",1571268);
>>> ("Aaron Mcdivitt",1454629);
>>> ("Aaron Reuben",1765247);
>>> ("Aaron Sardinha",1224806);
>>> ("Abbey Gowens",1267083);
>>> ("Abbey Hathcox",1309490);
>>> ...
>>>
>>> As the title say I'm running into problems compiling this when I
>>> create a large phone book, the error being:
>>>
>>> Camlp4: Uncaught exception: Stack_overflow
>>>
>>> This happens with 25K entries, it works with 10K entries.
>>>
>>> Is there some way I can prevent Camlp4 from being run on the Pb.ml
>>> file? Or will I just have to generate a file that builds the array at
>>> runtime somehow?
>>>
>>> AndrÃ
>>
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