Filters in Lua vs in Haskell

Filters in Lua vs in Haskell

[oliver]

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Hi there

The doco says Lua filters “are usually faster than JSON filters” and 
from my understanding Haskell filters are JSON filters.

So why are filters in Pandoc’s “native” language slower than 
filters in Lua?

Thanks for clarification!
Olli

On 29 May 2023, at 11:03, Michael Milton wrote:

> I just tried to render a PowerPoint presentation from markdown. 
> However the
> template I used is a bit odd, and I noticed that my title slide was 
> not
> populated with text, whereas the regular slides were. I wonder if 
> someone
> could explain the logic that Pandoc uses to find a text box to insert 
> text
> into? Is there a way to modify my template to avoid these issues?
>
> -- 
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Re: Filters in Lua vs in Haskell

[John MacFarlane]

Because JSON filters involve serializing the Haskell data structure to JSON, then decoding that back to a Haskell data structure, modifying it, encoding it to JSON, and decoding it back.  The Lua interface avoids all of this serialization/deserialization.

> On May 29, 2023, at 12:46 AM, oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> wrote:
> 
> Hi there
> 
> The doco says Lua filters “are usually faster than JSON filters” and from my understanding Haskell filters are JSON filters.
> 
> So why are filters in Pandoc’s “native” language slower than filters in Lua?
> 
> Thanks for clarification! 
> Olli
> 
> On 29 May 2023, at 11:03, Michael Milton wrote:
> 
> I just tried to render a PowerPoint presentation from markdown. However the template I used is a bit odd, and I noticed that my title slide was not populated with text, whereas the regular slides were. I wonder if someone could explain the logic that Pandoc uses to find a text box to insert text into? Is there a way to modify my template to avoid these issues? --
> You received this message because you are subscribed to the Google Groups "pandoc-discuss" group.
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> 
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Re: Filters in Lua vs in Haskell

[Oliver]

Thanks for this, John.

Do you know, is the performance hit big? Or nothing really to worry?

Regards,
Olli

On 30 May 2023, at 4:18, John MacFarlane wrote:

> Because JSON filters involve serializing the Haskell data structure to JSON, then decoding that back to a Haskell data structure, modifying it, encoding it to JSON, and decoding it back.  The Lua interface avoids all of this serialization/deserialization.
>
>> On May 29, 2023, at 12:46 AM, oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> wrote:
>>
>> Hi there
>>
>> The doco says Lua filters “are usually faster than JSON filters” and from my understanding Haskell filters are JSON filters.
>>
>> So why are filters in Pandoc’s “native” language slower than filters in Lua?
>>
>> Thanks for clarification!
>> Olli
>>
>> On 29 May 2023, at 11:03, Michael Milton wrote:
>>
>> I just tried to render a PowerPoint presentation from markdown. However the template I used is a bit odd, and I noticed that my title slide was not populated with text, whereas the regular slides were. I wonder if someone could explain the logic that Pandoc uses to find a text box to insert text into? Is there a way to modify my template to avoid these issues? --
>> You received this message because you are subscribed to the Google Groups "pandoc-discuss" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to pandoc-discuss+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
>> To view this discussion on the web visit https://groups.google.com/d/msgid/pandoc-discuss/874eb03a-f62b-4ee7-a582-30c798f22083n%40googlegroups.com.
>>
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>
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Re: Filters in Lua vs in Haskell

[John MacFarlane]

See the chart at the beginning of the Lua filters documentation for one data point.


> On May 30, 2023, at 3:46 PM, Oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> wrote:
> 
> Thanks for this, John.
> 
> Do you know, is the performance hit big? Or nothing really to worry?
> 
> Regards,
> Olli
> 
> On 30 May 2023, at 4:18, John MacFarlane wrote:
> 
>> Because JSON filters involve serializing the Haskell data structure to JSON, then decoding that back to a Haskell data structure, modifying it, encoding it to JSON, and decoding it back.  The Lua interface avoids all of this serialization/deserialization.
>> 
>>> On May 29, 2023, at 12:46 AM, oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> wrote:
>>> 
>>> Hi there
>>> 
>>> The doco says Lua filters “are usually faster than JSON filters” and from my understanding Haskell filters are JSON filters.
>>> 
>>> So why are filters in Pandoc’s “native” language slower than filters in Lua?
>>> 
>>> Thanks for clarification!
>>> Olli
>>> 
>>> On 29 May 2023, at 11:03, Michael Milton wrote:
>>> 
>>> I just tried to render a PowerPoint presentation from markdown. However the template I used is a bit odd, and I noticed that my title slide was not populated with text, whereas the regular slides were. I wonder if someone could explain the logic that Pandoc uses to find a text box to insert text into? Is there a way to modify my template to avoid these issues? --
>>> You received this message because you are subscribed to the Google Groups "pandoc-discuss" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an email to pandoc-discuss+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
>>> To view this discussion on the web visit https://groups.google.com/d/msgid/pandoc-discuss/874eb03a-f62b-4ee7-a582-30c798f22083n%40googlegroups.com.
>>> 
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>> 
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> 
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Re: Filters in Lua vs in Haskell

[Oliver]

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Thanks for the pointer, John.

 From this one data point, the JSON overhead seems to be *quite* 
substantial.

I guess I will look into Lua filters then…

Leo

On 31 May 2023, at 8:53, John MacFarlane wrote:

> See the chart at the beginning of the Lua filters documentation for 
> one data point.
>
>
>> On May 30, 2023, at 3:46 PM, Oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> 
>> wrote:
>>
>> Thanks for this, John.
>>
>> Do you know, is the performance hit big? Or nothing really to worry?
>>
>> Regards,
>> Olli
>>
>> On 30 May 2023, at 4:18, John MacFarlane wrote:
>>
>>> Because JSON filters involve serializing the Haskell data structure 
>>> to JSON, then decoding that back to a Haskell data structure, 
>>> modifying it, encoding it to JSON, and decoding it back.  The Lua 
>>> interface avoids all of this serialization/deserialization.
>>>
>>>> On May 29, 2023, at 12:46 AM, oliver <news-WPTjrydoUPgeaOpM6FAJmQkbCANdLtlA@public.gmane.org> 
>>>> wrote:
>>>>
>>>> Hi there
>>>>
>>>> The doco says Lua filters “are usually faster than JSON 
>>>> filters” and from my understanding Haskell filters are JSON 
>>>> filters.
>>>>
>>>> So why are filters in Pandoc’s “native” language slower than 
>>>> filters in Lua?
>>>>
>>>> Thanks for clarification!
>>>> Olli
>>>>
>>>> On 29 May 2023, at 11:03, Michael Milton wrote:
>>>>
>>>> I just tried to render a PowerPoint presentation from markdown. 
>>>> However the template I used is a bit odd, and I noticed that my 
>>>> title slide was not populated with text, whereas the regular slides 
>>>> were. I wonder if someone could explain the logic that Pandoc uses 
>>>> to find a text box to insert text into? Is there a way to modify my 
>>>> template to avoid these issues? --
>>>> You received this message because you are subscribed to the Google 
>>>> Groups "pandoc-discuss" group.
>>>> To unsubscribe from this group and stop receiving emails from it, 
>>>> send an email to pandoc-discuss+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
>>>> To view this discussion on the web visit 
>>>> https://groups.google.com/d/msgid/pandoc-discuss/874eb03a-f62b-4ee7-a582-30c798f22083n%40googlegroups.com.
>>>>
>>>> -- 
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>>>> https://groups.google.com/d/msgid/pandoc-discuss/EC2F53EB-56F2-4078-B8DF-5D35B64A7EC0%40halloleo.hailmail.net.
>>>
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>>
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