#### Read-only or read-and-write?

Read or write status is preserved when variables are imported in Python, and trying to modify their values will raise an error:

    >>> pi
    3.14159265359
    >>> print pi.__doc__ # pi was imported from SIC
    A SicVar instance.
    >>> pi[0] = 0
    Traceback (most recent call last):
      File "<STDIN>", line 1, in <module>
      File "/home/bardeau/gildas/gildas-src-dev/pc-fedora6-ifort/kernel/
    python/pgutils.py", line 204, in __setitem__
        raise PygildasValueError, "Variable is read-only in SIC."
    pgutils.PygildasValueError: Variable is read-only in SIC.

The protection of SicVar intances against deletion or re-definition (ie using pi = 1 instead of pi[0] = 1) is not implemented. See considerations in subsection .