-# Copyright (c) 2019 Cisco and/or its affiliates.
+# Copyright (c) 2021 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
"""Utility function for handling options without doubled or trailing spaces."""
-class OptionString(object):
+class OptionString:
"""Class serving as a builder for option strings.
- Motivation: Both manual contatenation and .join() methods
+ Motivation: Both manual concatenation and .join() methods
are prone to leaving superfluous spaces if some parts of options
are optional (missing, empty).
the best fitting one, without much logic near the call site.
"""
- def __init__(self, prefix="", *args):
+ def __init__(self, parts=tuple(), prefix=u""):
"""Create instance with listed strings as parts to use.
Prefix will be converted to string and stripped.
The typical (nonempty) prefix values are "-" and "--".
- :param prefix: Subtring to prepend to every parameter (not value).
- :param args: List of positional arguments to become parts.
+ TODO: Support users calling with parts being a string?
+
+ :param parts: List of stringifiable objects to become parts.
+ :param prefix: Substring to prepend to every parameter (not value).
+ :type parts: Iterable of object
:type prefix: object
- :type args: list of object
"""
+ self.parts = [str(part) for part in parts]
self.prefix = str(prefix).strip() # Not worth to call change_prefix.
- self.parts = list(args)
def __repr__(self):
"""Return string executable as Python constructor call.
:returns: Executable constructor call as string.
:rtype: str
"""
- return "".join([
- "OptionString(prefix=", repr(self.prefix), ",",
- repr(self.parts)[1:-1], ")"])
+ return f"OptionString(parts={self.parts!r},prefix={self.prefix!r})"
# TODO: Would we ever need a copy() method?
- # Currently, supersting "master" is mutable but unique,
+ # Currently, superstring "master" is mutable but unique,
# substring "slave" can be used to extend, but does not need to be mutated.
def change_prefix(self, prefix):
self.parts.extend(other.parts)
return self
- def _check_and_add(self, part, prefixed):
- """Convert to string, strip, add conditionally prefixed if non-empty.
+ def check_and_add(self, part, prefixed):
+ """Convert to string, strip, conditionally add prefixed if non-empty.
+ Value of None is converted to empty string.
Emptiness is tested before adding prefix.
+ This could be a protected method (name starting with underscore),
+ but then pylint does not understand add_equals and add_with_value
+ are allowed to call this on the temp instance.
+ TODO: Is there a way to make pylint understand?
+
:param part: Unchecked part to add to list of parts.
:param prefixed: Whether to add prefix when adding.
:type part: object
:returns: The converted part without prefix, empty means not added.
:rtype: str
"""
- part = str(part).strip()
+ part = u"" if part is None else str(part).strip()
if part:
prefixed_part = self.prefix + part if prefixed else part
self.parts.append(prefixed_part)
Parameter is prefixed before adding.
:param parameter: Parameter object, usually a word starting with dash.
- :type variable: object
+ :type parameter: object
:returns: Self, to enable method chaining.
:rtype: OptionString
"""
- self._check_and_add(parameter, prefixed=True)
+ self.check_and_add(parameter, prefixed=True)
return self
def add_if(self, parameter, condition):
:param parameter: Parameter object, usually a word starting with dash.
:param condition: Do not add if truth value of this is false.
- :type variable: object
+ :type parameter: object
:type condition: object
:returns: Self, to enable method chaining.
:rtype: OptionString
:param parameter: Parameter object, usually a word starting with dash.
:param value: Value object. Prefix is never added.
- :type variable: object
+ :type parameter: object
:type value: object
:returns: Self, to enable method chaining.
:rtype: OptionString
"""
temp = OptionString(prefix=self.prefix)
- # TODO: Is pylint really that ignorant?
- # How could it not understand temp is of type of this class?
- # pylint: disable=protected-access
- if temp._check_and_add(parameter, prefixed=True):
- if temp._check_and_add(value, prefixed=False):
+ if temp.check_and_add(parameter, prefixed=True):
+ if temp.check_and_add(value, prefixed=False):
self.extend(temp)
return self
:param parameter: Parameter object, usually a word starting with dash.
:param value: Value object. Prefix is never added.
- :type variable: object
+ :type parameter: object
:type value: object
:returns: Self, to enable method chaining.
:rtype: OptionString
"""
temp = OptionString(prefix=self.prefix)
- # pylint: disable=protected-access
- if temp._check_and_add(parameter, prefixed=True):
- if temp._check_and_add(value, prefixed=False):
- self.parts.append("=".join(temp.parts))
+ if temp.check_and_add(parameter, prefixed=True):
+ if temp.check_and_add(value, prefixed=False):
+ self.parts.append(u"=".join(temp.parts))
return self
def add_with_value_if(self, parameter, value, condition):
:param parameter: Parameter object, usually a word starting with dash.
:param value: Value object. Prefix is never added.
:param condition: Do not add if truth value of this is false.
- :type variable: object
+ :type parameter: object
:type value: object
:type condition: object
:returns: Self, to enable method chaining.
:param parameter: Parameter object, usually a word starting with dash.
:param value: Value object. Prefix is never added.
:param condition: Do not add if truth value of this is false.
- :type variable: object
+ :type parameter: object
:type value: object
:type condition: object
:returns: Self, to enable method chaining.
self.add_equals(parameter, value)
return self
- def add_with_value_from_dict(self, parameter, key, mapping, default=""):
+ def add_with_value_from_dict(self, parameter, key, mapping, default=u""):
"""Add parameter with value from dict under key, or default.
If key is missing, default is used as value.
value = mapping.get(key, default)
return self.add_with_value(parameter, value)
- def add_equals_from_dict(self, parameter, key, mapping, default=""):
+ def add_equals_from_dict(self, parameter, key, mapping, default=u""):
"""Add parameter=value to options where value is from dict.
If key is missing, default is used as value.
value = mapping.get(key, default)
return self.add_equals(parameter, value)
- def add_if_from_dict(self, parameter, key, mapping, default="False"):
+ def add_if_from_dict(self, parameter, key, mapping, default=u"False"):
"""Add parameter based on if the condition in dict is true.
If key is missing, default is used as condition.
return self.add_if(parameter, condition)
def add_with_value_if_from_dict(
- self, parameter, value, key, mapping, default="False"):
+ self, parameter, value, key, mapping, default=u"False"):
"""Add parameter and value based on condition in dict.
If key is missing, default is used as condition.
return self.add_with_value_if(parameter, value, condition)
def add_equals_if_from_dict(
- self, parameter, value, key, mapping, default="False"):
+ self, parameter, value, key, mapping, default=u"False"):
"""Add parameter=value based on condition in dict.
If key is missing, default is used as condition.
:returns: Space separated string of options.
:rtype: str
"""
- return " ".join(self.parts)
+ return u" ".join(self.parts)