stringbuilder.py

#!/usr/bin/env python3.8
# -*- coding: utf-8 -*-
#
# Copyright 2020-2025 by Murray Altheim. All rights reserved. This file is part
# of the Robot Operating System project, released under the MIT License. Please
# see the LICENSE file included as part of this package.
#
# author:   Murray Altheim
# created:  2021-10-15
# modified: 2021-10-15
#

from io import StringIO

# ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
class StringBuilder():
    NONE = ''
    '''
    Mimics Java's StringBuilder class, because we miss it.

    :param init_obj:  the optional initial object to be appended to the buffer.
                      Note that this does not include the indent.
    :param indent:    the optional number of characters of whitespace to indent
    :param delim:     the optional delimiter to be written after each appended object.
    '''
    def __init__(self, init_obj=None, indent=0, delim=None):
        self._buffer = StringIO()
        self._delim = delim
        self._indent = None
        if init_obj:
            self.append(init_obj)
        if indent > 0:
            self._indent = ' ' * indent

    # ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
    def append(self, obj, indent=None, delim=None):
        '''
        Append the object to the buffer. This accepts any object.

        :param indent: the optional indent as the number of whitespace characters.
                       If supplied, this overrides any class-level indent.
        :param delim:  the optional delimiter to be written after the object.
                       If supplied, this overrides any class-level delimiter.
        '''
        if obj == None:
            raise TypeError('null argument')
        if indent:
            self._buffer.write(' ' * indent)
        elif self._indent:
            self._buffer.write(self._indent)
        if isinstance(obj, str):
            self._buffer.write(obj)
        else:
            self._buffer.write(str(obj))
        if delim or delim == StringBuilder.NONE:
            self._buffer.write(delim)
        elif self._delim:
            self._buffer.write(self._delim)

    # ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
    def length(self):
        return len(self._buffer.getvalue())

    # ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
    def __str__(self):
        return self._buffer.getvalue()

    # ┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
    def to_string(self):
        return self._buffer.getvalue()

#EOF