[erlang-questions] Generating Core Erlang -- Re: Dangers of generating a large erlang module

Erik Søe Sørensen <>
Sun Sep 29 20:56:16 CEST 2013


I think the direct way would be to generate the internal form of CE, then
feed it to the compiler; don't know exactly how easy they've made it :-)
Although I hope it's not too complicated; if you/we figure it out, I might
update mochiglobal to use it, given time.
Den 29/09/2013 20.24 skrev "Ivan uemlianin" <>:

> That's what I've just done :D  Core Erlang looks very verbose but quite
> regular & probably not difficult to generate.
>
> My questions now are:
> - are there any libraries "out there" for generating Core Erlang, or do we
> all roll our own?
> - how would one use compile:file or compile:forms with core erlang? I
> haven't been able to find any documentation (haven't read Richard
> Carlsson's Introduction paper yet).
>
> Many thanks
>
> Ivan
>
> --
> festina lente
>
>
> On 29 Sep 2013, at 18:36, Erik Søe Sørensen <> wrote:
>
> Core Erlang is an intermediate  representation in the Erlang compiler -
> but also (afaik) a fairly well-defined/public one and one that is stable.
> I don't think you'll find much in the vein of tutorials. Try getting erlc
> to output the intermediate format, though, for a small program similar to
> what you'll be using it for.
> Den 29/09/2013 19.20 skrev "Ivan uemlianin" <>:
>
>> Thanks! I think I'll try and head in that direction. I've had a few goes
>> at other methods (db lookup etc) and they're much slower than this "dynamic
>> hardcoding"). I'll sniff around for Core Erlang tutorials.
>>
>> Best wishes
>>
>> Ivan
>>
>>
>> --
>> festina lente
>>
>>
>> On 29 Sep 2013, at 17:48, Erik Søe Sørensen <> wrote:
>>
>> A thing which I discovered recently (in connection with mochiglobal) is
>> that compiling code containing large binaries, or large amounts of
>> binaries,  is quite memory-intensive. As I recall it, the numbers were ~64
>> bytes of RAM per byte in a binary metal; twice as much if on a 64 bit
>> emulator.
>> Which means that if you want to compile modules containing (in sum)
>> multimegabyte binaries, doing so from Erlang source or from full Erlang AST
>> is a no-go.  Iirc, it is feasible if starting from Core Erlang.
>> /Erik
>> Den 29/09/2013 12.50 skrev "Ivan Uemlianin" <>:
>>
>>> Dear Anthony
>>>
>>> Thanks for your comment.
>>>
>>> Yes, that's exactly what the generated module is doing.  The generated
>>> module has a single function with many clauses like this:
>>>
>>>     f(<<"trigger", Rest/binary) -> ...
>>>
>>> This is why (as far as I can work out) the generated code has to be so
>>> big.
>>>
>>> I prefer the idea of generating and loading code to, say, updating a
>>> database table, because it seems faster and less likely to lead to
>>> bottlenecks.
>>>
>>> Best wishes
>>>
>>> Ivan
>>>
>>>
>>> On 29/09/2013 11:38, Anthony Ramine wrote:
>>>
>>>> Hello Ivan,
>>>>
>>>> Out of curiosity, what does it look like?
>>>>
>>>> Pattern matching on literal values in Erlang is done with a binary
>>>> search over the sorted list of patterns, I am not sure this would play well
>>>> with your use case even if the compilation didn't bring the VM down.
>>>>
>>>> Regards,
>>>>
>>>> Le 29 sept. 2013 à 11:29, Ivan Uemlianin a écrit :
>>>>
>>>>  All goes well on small test files, but the files I want to use IRL are
>>>>> relatively large --- around 120,000 lines.
>>>>>
>>>>
>>>>
>>> --
>>> ==============================**==============================
>>> Ivan A. Uemlianin PhD
>>> Llaisdy
>>> Speech Technology Research and Development
>>>
>>>                     
>>>                      www.llaisdy.com
>>>                          llaisdy.wordpress.com
>>>               github.com/llaisdy
>>>                      www.linkedin.com/in/**ivanuemlianin<http://www.linkedin.com/in/ivanuemlianin>
>>>
>>>                         festina lente
>>> ==============================**==============================
>>> ______________________________**_________________
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>>
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