casa6

import traceback

from IPython.core.error import InputRejected

from casa_stack_manip import stack_find

​

__casa = stack_find('casa')

​

​

if __casa.has_key('state') and __casa['state'].has_key('init_version') and __casa['state']['init_version'] > 0:

​

    #### this provides two functions:

    ####      register_builtin(str or [str]) - register builtin values

    ####      enable_builtin_protection( )   - turn on builtin value protection

    import ast

​

    def static_var(varname, value):

        def decorate(func):

            setattr(func, varname, value)

            return func

        return decorate

​

    @static_var("builtin_dict", stack_find('casa_builtins','root'))

    def register_builtin( obj ):

        if isinstance(obj,str):

            register_builtin.builtin_dict[obj] = True

        elif isinstance(obj, list) and all(isinstance(elem, str) for elem in obj):

            for b in obj: register_builtin.builtin_dict[b] = True

        else:

            raise RuntimeError("parameter is not a string or list of strings")

​

    class __check_builtin(ast.NodeTransformer):

        """prevent assignment to builtin values"""

        def __init__(self):

            self.casa_builtins = stack_find('casa_builtins','root')

        def visit_FunctionDef(self, node):

            return node

        def visit_Assign(self, node):

            try:

                for n in node.targets:

                    # CASA <1>: def foobar( ): return (1,2,3)

                    # CASA <2>: True,b,c = foobar( )

                    #

                    #           generates a [<ast.Tuple>] for 'node'

                    #           and tuple.elts provides access to the

                    #           strings/names within the ast.Tuple

                    #

                    tgts = n.elts if isinstance(n,ast.Tuple) else [n]

                    for t in tgts:

                        if not isinstance(t,ast.Attribute) and \

                           not isinstance(t,ast.Subscript):

                            if __builtins__.has_key(t.id):

                                raise InputRejected("attempt to modify a python builtin value")

                            if self.casa_builtins.has_key(t.id):

                                raise InputRejected("attempt to modify a casa builtin value")

            except InputRejected as ir:

                raise ir

            except:

                print "-----------------------------------------------------------------"

                print "internal error in CASA assignment filter..."

                print traceback.format_exc()

                print "-----------------------------------------------------------------"

            return node

        def visit_Lambda(self, node):

            return node

​

    @static_var("ip",get_ipython( ))

    def enable_builtin_protection( ):

        enable_builtin_protection.ip.ast_transformers.append(__check_builtin( ))

​

else:

​

    def enable_builtin_protection( ):

        pass

​

    def register_builtin( obj ):

        if not isinstance(obj,str) or not isinstance(obj, list) or not all(isinstance(elem, str) for elem in obj):

            raise RuntimeError("parameter is not a string or list of strings")