# This code is part of Qiskit.
#
# (C) Copyright IBM 2017.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""Node for an OPENQASM prefix expression."""

from .node import Node


class Prefix(Node):
    """Node for an OPENQASM prefix expression.

    children[0] is a unary operator node.
    children[1] is an expression node.
    """

    def __init__(self, children):
        """Create the prefix node."""
        super().__init__("prefix", children, None)

    def qasm(self):
        """Return the corresponding OPENQASM string."""
        return self.children[0].value + "(" + self.children[1].qasm() + ")"

    def latex(self):
        """Return the corresponding math mode latex string."""
        try:
            from pylatexenc.latexencode import utf8tolatex
        except ImportError as ex:
            raise Exception(
                "pylatexenc", "latex-from-qasm exporter", "pip install pylatexenc"
            ) from ex
        return utf8tolatex(self.sym())

    def real(self):
        """Return the correspond floating point number."""
        operation = self.children[0].operation()
        expr = self.children[1].real()
        return operation(expr)

    def sym(self, nested_scope=None):
        """Return the correspond symbolic number."""
        operation = self.children[0].operation()
        expr = self.children[1].sym(nested_scope)
        return operation(expr)
