Re: Problem with arguments in macro

[Hans Hagen <pragma@wxs.nl>]

On 1/21/2013 8:47 PM, PELLOUIN Christophe wrote:
> Le 21/01/2013 19:32, Hans Hagen a écrit :
>> On 1/21/2013 7:26 PM, PELLOUIN Christophe wrote:
>>> Hello,
>>>
>>> When writing a macro, I observed that some arguments are not transmitted
>>> correctly, particularly when the type is defined as "text".
>>> Here is an example with the macro max defined in the file plain.mp
>>> With this program:
>>>
>>>      beginfig(1)
>>>
>>>          show("first test");
>>>          show max (1,2,8,5,15,2,1,4);
>>>
>>>          numeric u_;
>>>          v_=15;
>>>          show("second test");
>>>          show max (1,2,8,5,v_,2,1,4);
>>>
>>>          numeric u_;
>>>          u_=15    % u_ variable is also defined in the macro max
>>>          show("third test");
>>>          show max (1,2,8,5,u_,2,1,4);
>>>
>>>      endfig;
>>>      end
>>>
>>> The result is:
>>>
>>>      This is MetaPost, version 1.504 (kpathsea version 6.0.1)
>>>      (mpost.mp (c:/texlive/2011/texmf-dist/metapost/base/plain.mp
>>>      Preloading the plain mem file, version 1.004)) (./bizzare.mp
>>>      >> "first test"
>>>      >> 15
>>>      >> "second test"
>>>      >> 15
>>>      >> "third test"
>>>      >> 8 [1] )
>>>      1 output file written: bizzare.1
>>>      Transcript written on bizzare.log.
>>>
>>>
>>>
>>> The third result is different because the variable u_ is defined in the
>>> macro max of the file plain.mp
>>
>> I can protect all local plain variables if needed but I'll only do it
>> if someone then tests all the plain macros.
>
> How can I protect a variable? I had the same bug in one of my macros and
> I'd like to fix it.

my_private_u

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