取消变量

通过取消变量或函数定义来释放内存。详情请参考 undef.

$ undef all;

$ x=1;
$ undef(`x, VAR);

$ x=1; y=2;
$ undef(`x`y, VAR);

$ share table(1..3 as x, 4..6 as y) as t;
$ undef(`t, SHARED);

$ def f(a){return a+1};
$ undef(`f, DEF);

$ a=1; b=2;
$ undef all, VAR;
//取消定义所有变量,但不包括函数定义。