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

Ivan uemlianin <>
Sun Sep 29 20:24:45 CEST 2013


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
>>>> 
>>>>                         festina lente
>>>> ============================================================
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>>>> 
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