It was discussed before, but not in extension and afaik without a solution so
far. Sometimes I want to rewrite built-in modules or functions in order to
e.g. extend their parameter list and functionality. The problem: "after" and
within that code I loose access to the built-in symbols. So particularly
there is no way back if the rewrite happens within a lib.

Say I want to rewrite cube() in a lib to get rid of the cumbersome brackets
and default it to center=true, e.g. by:

cube(10, 20, 1);
module cube(size=1, y=1, z=1, center = true, x=undef)
{
x = is_undef(x)?size:x;
if (is_undef(x[0])) cube([x, y, z], center=center); else cube(x, center);
}

This obviously results in a recursion error. So I have to use a naming
convention:

module cube_(size=1, y=1, z=1, center = true, x=undef)
{
x = is_undef(x)?size:x;
if (is_undef(x[0])) cube([x, y, z], center=center); else cube(x, center);
}

I'd rather like to write something like
module cube(size=1, y=1, z=1, center = true, x=undef)
{
x = is_undef(x)?size:x;
if (is_undef(x[0])) $cube([x, y, z], center=center); else $cube(x,
center);
}

and then if necessary be able to switch back to the built-in version by

module cube(size=1, center=false)  $cube(size, center);

--
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+1
I too have desired this for some time.
There is one significant downside, that being supportability, if cube() no
longer behaves as it seemingly should, possibly due to something berried in
a library three layers deep, it is going to drive people insane...

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