Re: gnuplot module broken

[Mojca Miklavec <mojca.miklavec.lists@gmail.com>]

Dear Hans,

please consider the following example in MKII:

\setupcolors[state=start]

\starttext

\startMPextensions
a := \abc;
color b;
b := \MPcolor{currentcolor};
\stopMPextensions

\startuseMPgraphic{bla}
fill fullcircle scaled a withcolor b;
\stopuseMPgraphic

\def\abc{3cm}\color[blue]{\useMPgraphic{bla}}

% Nice small black circle
\def\abc{1cm}\useMPgraphic{bla}

\stoptext


I still don't know how to reproduce this in MKIV. I tried with
MPdefinitions as you suggested, but this only works the first time
when it is used. The following example creates two equal circles
instead of two different ones:


\starttext

\startMPdefinitions
a := \abc;
color b;
b := \MPcolor{currentcolor};
\stopMPdefinitions

\startuseMPgraphic{bla}
fill fullcircle scaled a withcolor b;
\stopuseMPgraphic

\def\abc{3cm}\color[blue]{\useMPgraphic{bla}}

% I want a black 1cm circle here
\def\abc{1cm}\useMPgraphic{bla}

\stoptext


Unless MKII is more powerful than MKIV: how can I achieve the same
functionality in MKIV as I did in MKII?

Thank you,
    Mojca


On Tue, Feb 19, 2013 at 10:36 AM, Hans Hagen wrote:
> On 2/19/2013 1:37 AM, Mojca Miklavec wrote:
>>
>> On Mon, Feb 18, 2013 at 5:40 PM, Marco Patzer wrote:
>>>
>>> Hi Mojca et al.
>>>
>>> todays beta broke the gnuplot module. This is probably due to the
>>> changes in the MP inclusion mechanism.
>>>
>>> \usemodule [gnuplot]
>>> \starttext
>>> \stoptext
>>
>> Here's an almost minimal example:
>>
>> \def\abc{1cm}
>>
>> \startMPextensions
>> a := \abc;
>> color b;
>> b := \MPcolor{currentcolor};
>> \stopMPextensions
>>
>> \def\abc{3cm}
>>
>> \starttext
>> \startcolor[blue]
>> \startMPcode
>> fill fullcircle scaled a withcolor b;
>> \stopMPcode
>> \stopcolor
>> \stoptext
>>
>> The old ConTeXt draws a blue circle with diameter 3cm and the new
>> ConTeXt draws a black circle with diameter 1cm. Which one is right?
>>  From a recent message by Hans:
>>
>>> - add mp functionality (immediate expansion)
>>
>>
>> It seems that ConTeXt now parses everything inside MPextensions
>> earlier than it did before and I don't have the slightest idea how to
>> account for this in the module without a major rewrite. In case that
>> Hans wants to keep the new functionality, I either need [quite some]
>> help with the module or I'll simply stick to TeX Live 2012 for the
>> foreseeable future ;)
>
>
> For the (not texlive) module use:
>
> \defineMPinstance[gnuplot]
>   [format=metafun,
>    extensions=yes,
>    initializations=yes,
>    method=double]
>
> \startMPdefinitions[gnuplot] ...
>
> and then use the gnuplot instance. This not only isolates the code, but also
> gives you floats. It also means that if someone crashes the gnuplot
> instance, the rest still keeps running.
>
> Definitions are per instance and are delayed i.e. passed via the tex end
> when they get expanded.
>
> The reason for extensions being immediate (at least for now) is that it was
> more easy to implement as extensions meant for mp extensions and can be for
> all instances of specific (sets) of instances.
>
> Sorry for the changes but as we have multiple instances, scale vs double and
> maybe more coming it's probably worth the trouble.
>
> Hans
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