[metapost] how to get the size of an array

[Manuel Yguel]

Hello,
I have two questions:

1) suppose I have an array defined like that

numeric range[];

rang[1]:=3; ...

how can I now the size of this array ?

2) is there equivalent of fopen, fscanf functions in metapost to read
through a file ?
I know that there is the package graph for handling data files, but I want
to do something more complex than what is proposed in this package.


Thank you for your answers,

Manuel