Re: How can I keep these values local to my function?

["Ruud H.G. van Tol" <rvtol@isolution.nl>]

On 2024-09-11 03:15, Joe Slater wrote:
> I want to be able to specify binary combinations of options the way 
> that, e.g., vecsort() does. I couldn't see a way to do that so I 
> created a function, makeoptions(), that returns a vector in the form 
> ["a=1","b=2",...] and I use eval() on that vector to create those 
> variables within my function. My problem is that eval() creates them 
> with global scope, and I can't see a way to make them local.
>
> /* Takes a string containing a list of option names and a number whose 
> binary digits represents those options. Returns variables set 
> accordingly. */
> makeoptions(s="",options=0)=
> {
> if(s=="",return());
> my(v=strsplit(s," "));
> return(vector(#v,i,(Str(v[i],"=",bitand(2^(i-1),options)<>0))))
> }
> /* A function that uses makeoptions() */
> f(n)={
> my(a=eval(makeoptions("One Two Three",n)));
> my(b=eval(makeoptions("Four Five Six",n+1)));
> print("a=",One,Two,Three);
> print("b=",Four,Five,Six);
> }
>
> Here's the output from my function:
> (10:31) > f(2)
> a=010
> b=110
> (10:31) > One \\ Should be undefined
> %2 = 0
> (10:32) > Four \\ Should be undefined
> %3 = 1
> Is there a way to make these variables local, or another way to 
> achieve what I want: local named variables set at run time without 
> having a routine along the lines of Opt1=bitand(options,1); 
> Opt2=bitand(options,2); ...

Where you say "local", I think you mean "lexical".

Maybe user defined "Member functions" could be used,
to generate that a.Two means 1.

-- Ruud