force evaluation of the first argument of the functionwith_stdout

hi,

write the filename between "". For further details check

describe(with_stdout)

which includes an example of using with_stdout inside a function, i.e.

    mygnuplot(f,var,range,number_ticks):=
     block([numer:true,display2d:false],
     with_stdout("/tmp/gnu",
       for x:range[1] thru range[2] step
                    (range[2]-range[1])/number_ticks
          do (print(x,at(f,var=x)))),
     system("echo \"set data style lines; set title '",
            f,"' ;plot '/tmp/gnu'
    ;pause 10 \" | gnuplot"));


Miquel


On Wed, 2005-11-30 at 13:14 +0100, jcano wrote:
> Hi,
> 
> How can I do force evaluation of the first argument of the function 
> with_stdout.
> 
> More precisely, I am trying to write a function to write a geomview file 
> in order to plot a parametric curve. The code is this:
> 
> geomview_curve(list,range,nticks,file_name):=block(
>   [t,numer:true,display2d:false],
>   with_stdout(file_name,
>   print("VECT"),
>   print("1 ",nticks," 1"),
>   print(nticks),
>   print("1"),
>   for t:range[2] thru range[3] step (range[3]-range[2])/nticks do
>   print( ev(subst(t,range[1],list[1]),float),
>     ev(subst(t,range[1],list[2]),float),
>     ev(subst(t,range[1],list[3]),float)),
>   print("1 0 0 1")
> ));
> 
> For any call, for instance geomview_curve(...,"curva"),
> it always write a file named "$file_name" and not "curva".
> 
> I have seen a similar question in the mailing list but no answer.
> 
> Thanks in advances,
> jose cano
> 
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