__license__ = """
NML is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

NML is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with NML; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA."""

from nml import generic
from .base_expression import Type, Expression

class Boolean(Expression):
    """
    Convert to boolean truth value.

    @ivar expr: (Integer) expression to convert.
    @type expr: C{Expression}
    """
    def __init__(self, expr, pos = None):
        Expression.__init__(self, pos)
        self.expr = expr

    def debug_print(self, indentation):
        generic.print_dbg(indentation, 'Force expression to boolean:')
        self.expr.debug_print(indentation + 2)

    def reduce(self, id_dicts = [], unknown_id_fatal = True):
        expr = self.expr.reduce(id_dicts)
        if expr.type() != Type.INTEGER:
            raise generic.ScriptError("Only integers can be converted to a boolean value.", self.pos)
        if expr.is_boolean(): return expr
        return Boolean(expr)

    def supported_by_action2(self, raise_error):
        return self.expr.supported_by_action2(raise_error)

    def supported_by_actionD(self, raise_error):
        return self.expr.supported_by_actionD(raise_error)

    def collect_references(self):
        return self.expr.collect_references()

    def is_boolean(self):
        return True

    def __str__(self):
        return "!!({})".format(self.expr)
