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15 changes: 15 additions & 0 deletions launch/launch/conditions/launch_configuration_equals.py
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@

from typing import Optional
from typing import Text
import warnings

from ..condition import Condition
from ..launch_context import LaunchContext
Expand All @@ -36,13 +37,27 @@ class LaunchConfigurationEquals(Condition):

If ``None`` is provided instead of a string expression, then the condition
evaluates to ``True`` if the launch configuration is not set.

.. deprecated:: 1.1.0
Replaced by the more universally usable substitutions:
'EqualsSubstitution' and 'NotEqualsSubstitution'
"""

def __init__(
self,
launch_configuration_name: Text,
expected_value: Optional[SomeSubstitutionsType]
) -> None:
warnings.warn(
"The 'LaunchConfigurationEquals' and 'LaunchConfigurationNotEquals' Conditions are "
" deprecated. Use the 'EqualsSubstitution' and 'NotEqualsSubstitution' substitutions "
'instead! E.g.:\n'
' IfCondition(\n '
"\tEqualsSubstitution(LaunchConfiguration('some_launch_arg'), \"some_equality_check\")"
'\n )',
UserWarning
)

self.__launch_configuration_name = launch_configuration_name
if expected_value is not None:
self.__expected_value = normalize_to_list_of_substitutions(expected_value)
Expand Down
5 changes: 5 additions & 0 deletions launch/launch/conditions/launch_configuration_not_equals.py
Original file line number Diff line number Diff line change
Expand Up @@ -34,13 +34,18 @@ class LaunchConfigurationNotEquals(LaunchConfigurationEquals):

If ``None`` is provided instead of a string expression, then the condition
evaluates to ``True`` if the launch configuration is set.

.. deprecated:: 1.1.0
Replaced by the more universally usable substitutions:
'EqualsSubstitution' and 'NotEqualsSubstitution'
"""

def __init__(
self,
launch_configuration_name: Text,
expected_value: Optional[SomeSubstitutionsType]
) -> None:
# This is deprecated! Use `NotEqualsSubstitution` instead!
super().__init__(launch_configuration_name, expected_value)

def _predicate_func(self, context: LaunchContext) -> bool:
Expand Down
8 changes: 8 additions & 0 deletions launch/launch/substitutions/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -15,14 +15,18 @@
"""Package for substitutions."""

from .anon_name import AnonName
from .boolean_substitution import AllSubstitution
from .boolean_substitution import AndSubstitution
from .boolean_substitution import AnySubstitution
from .boolean_substitution import NotSubstitution
from .boolean_substitution import OrSubstitution
from .command import Command
from .environment_variable import EnvironmentVariable
from .equals_substitution import EqualsSubstitution
from .find_executable import FindExecutable
from .launch_configuration import LaunchConfiguration
from .local_substitution import LocalSubstitution
from .not_equals_substitution import NotEqualsSubstitution
from .path_join_substitution import PathJoinSubstitution
from .python_expression import PythonExpression
from .substitution_failure import SubstitutionFailure
Expand All @@ -31,14 +35,18 @@
from .this_launch_file_dir import ThisLaunchFileDir

__all__ = [
'AllSubstitution',
'AndSubstitution',
'AnySubstitution',
'AnonName',
'Command',
'EqualsSubstitution',
'EnvironmentVariable',
'FindExecutable',
'LaunchConfiguration',
'LocalSubstitution',
'NotSubstitution',
'NotEqualsSubstitution',
'OrSubstitution',
'PathJoinSubstitution',
'PythonExpression',
Expand Down
97 changes: 94 additions & 3 deletions launch/launch/substitutions/boolean_substitution.py
Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ class AndSubstitution(Substitution):
"""Substitution that returns 'and' of the input boolean values."""

def __init__(self, left: SomeSubstitutionsType, right: SomeSubstitutionsType) -> None:
"""Create a AndSubstitution substitution."""
"""Create an AndSubstitution substitution."""
super().__init__()

self.__left = normalize_to_list_of_substitutions(left)
Expand Down Expand Up @@ -113,15 +113,15 @@ class OrSubstitution(Substitution):
"""Substitution that returns 'or' of the input boolean values."""

def __init__(self, left: SomeSubstitutionsType, right: SomeSubstitutionsType) -> None:
"""Create a AndSubstitution substitution."""
"""Create an OrSubstitution substitution."""
super().__init__()

self.__left = normalize_to_list_of_substitutions(left)
self.__right = normalize_to_list_of_substitutions(right)

@classmethod
def parse(cls, data: Iterable[SomeSubstitutionsType]):
"""Parse `AndSubstitution` substitution."""
"""Parse `OrSubstitution` substitution."""
if len(data) != 2:
raise TypeError('and substitution expects 2 arguments')
return cls, {'left': data[0], 'right': data[1]}
Expand Down Expand Up @@ -152,3 +152,94 @@ def perform(self, context: LaunchContext) -> Text:
raise SubstitutionFailure(e)

return str(left_condition or right_condition).lower()


@expose_substitution('any')
class AnySubstitution(Substitution):
"""
Substitutes to the string 'true' if at least one of the input arguments evaluates to true.

If none of the arguments evaluate to true, then this substitution returns the string 'false'.
"""

def __init__(self, *args: SomeSubstitutionsType) -> None:
"""
Create an AnySubstitution substitution.

The following string arguments evaluate to true: '1', 'true', 'True', 'on'
"""
super().__init__()

self.__args = [normalize_to_list_of_substitutions(arg) for arg in args]

@classmethod
def parse(cls, data: Iterable[SomeSubstitutionsType]):
"""Parse `AnySubstitution` substitution."""
return cls, {'args': data}

@property
def args(self) -> Substitution:
"""Getter for args."""
return self.__args

def describe(self) -> Text:
"""Return a description of this substitution as a string."""
return f'AnySubstitution({" ".join(self.args)})'

def perform(self, context: LaunchContext) -> Text:
"""Perform the substitution."""
substituted_conditions = []
for arg in self.args:
try:
arg_condition = perform_typed_substitution(context, arg, bool)
substituted_conditions.append(arg_condition)
except (TypeError, ValueError) as e:
raise SubstitutionFailure(e)

return str(any(substituted_conditions)).lower()


@expose_substitution('all')
class AllSubstitution(Substitution):
"""
Substitutes to the string 'true' if all of the input arguments evaluate to true.

If any of the arguments evaluates to false, then this substitution returns the string 'false'.
"""

def __init__(self, *args: SomeSubstitutionsType) -> None:
"""
Create an AllSubstitution substitution.

The following string arguments evaluate to true: '1', 'true', 'True', 'on'
The following string arguments evaluate to false: '0', 'false', 'False', 'off'
"""
super().__init__()

self.__args = [normalize_to_list_of_substitutions(arg) for arg in args]

@classmethod
def parse(cls, data: Iterable[SomeSubstitutionsType]):
"""Parse `AllSubstitution` substitution."""
return cls, {'args': data}

@property
def args(self) -> Substitution:
"""Getter for args."""
return self.__args

def describe(self) -> Text:
"""Return a description of this substitution as a string."""
return f'AllSubstitution({" ".join(self.args)})'

def perform(self, context: LaunchContext) -> Text:
"""Perform the substitution."""
substituted_conditions = []
for arg in self.args:
try:
arg_condition = perform_typed_substitution(context, arg, bool)
substituted_conditions.append(arg_condition)
except (TypeError, ValueError) as e:
raise SubstitutionFailure(e)

return str(all(substituted_conditions)).lower()
119 changes: 119 additions & 0 deletions launch/launch/substitutions/equals_substitution.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,119 @@
# Copyright 2022 Open Source Robotics Foundation, Inc.
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Module for the EqualsSubstitution substitution."""

import math

from typing import Any
from typing import Iterable
from typing import Optional
from typing import Text
from typing import Union

from ..frontend import expose_substitution
from ..launch_context import LaunchContext
from ..some_substitutions_type import SomeSubstitutionsType
from ..substitution import Substitution
from ..utilities import normalize_to_list_of_substitutions
from ..utilities.type_utils import is_substitution, perform_substitutions


def _str_is_bool(input_str: Text) -> bool:
"""Check if string input is convertible to a boolean."""
if not isinstance(input_str, Text):
return False
else:
return input_str.lower() in ('true', 'false', '1', '0')


def _str_is_float(input_str: Text) -> bool:
"""Check if string input is convertible to a float."""
try:
float(input_str)
return True
except ValueError:
return False


@expose_substitution('equals')
class EqualsSubstitution(Substitution):
"""
Substitution that checks if two inputs are equal.

Returns 'true' or 'false' strings depending on the result.
"""

def __init__(
self,
left: Optional[Union[Any, Iterable[Any]]],
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I'm curios why this isn't just:

Suggested change
left: Optional[Union[Any, Iterable[Any]]],
left: SomeSubstitutionsType,

Same for the below.

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@methylDragon methylDragon Sep 8, 2022

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Using SomeSubstitutionsType means we can't have basic types as inputs (e.g. bool, numeric types, None) when it would be conceivable that a user might use them (at least via Python, maybe not the xml frontend)

Though I guess users could just str() it if we remove it... What do you think?

right: Optional[Union[Any, Iterable[Any]]]
) -> None:
"""Create an EqualsSubstitution substitution."""
super().__init__()

if not is_substitution(left):
if left is None:
left = ''
elif isinstance(left, bool):
left = str(left).lower()
else:
left = str(left)

if not is_substitution(right):
if right is None:
right = ''
elif isinstance(right, bool):
right = str(right).lower()
else:
right = str(right)

self.__left = normalize_to_list_of_substitutions(left)
self.__right = normalize_to_list_of_substitutions(right)

@classmethod
def parse(cls, data: Iterable[SomeSubstitutionsType]):
"""Parse `EqualsSubstitution` substitution."""
if len(data) != 2:
raise TypeError('and substitution expects 2 arguments')
return cls, {'left': data[0], 'right': data[1]}

@property
def left(self) -> Substitution:
"""Getter for left."""
return self.__left

@property
def right(self) -> Substitution:
"""Getter for right."""
return self.__right

def describe(self) -> Text:
"""Return a description of this substitution as a string."""
return f'EqualsSubstitution({self.left} {self.right})'

def perform(self, context: LaunchContext) -> Text:
"""Perform the substitution."""
left = perform_substitutions(context, self.left)
right = perform_substitutions(context, self.right)

# Special case for booleans
if _str_is_bool(left) and _str_is_bool(right):
return str((left.lower() in ('true', '1')) == (right.lower() in ('true', '1'))).lower()

# Special case for floats (epsilon closeness)
if _str_is_float(left) and _str_is_float(right):
return str(math.isclose(float(left), float(right))).lower()

return str(left == right).lower()
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This leaves me wondering about special cases, like float comparison. We're obviously comparing strings here, and that works for most situations, but I think we should expand the documentation of these to clarify what we're doing and what we're returning, i.e. none of the doc blocks mention we're returning the string true or false as a result of these substitutions.

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I am now supporting float comparisons. I will stop short of complex numbers though 😬

See tests

The docblocks also mention returning booleans-as-strings now

50 changes: 50 additions & 0 deletions launch/launch/substitutions/not_equals_substitution.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,50 @@
# Copyright 2022 Open Source Robotics Foundation, Inc.
#
# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Module for the NotEqualsSubstitution substitution."""

from typing import Any
from typing import Iterable
from typing import Optional
from typing import Text
from typing import Union

from .equals_substitution import EqualsSubstitution
from ..frontend import expose_substitution
from ..launch_context import LaunchContext


@expose_substitution('not-equals')
class NotEqualsSubstitution(EqualsSubstitution):
"""
Substitution that checks if two inputs are not equal.

Returns 'true' or 'false' strings depending on the result.
"""

def __init__(
self,
left: Optional[Union[Any, Iterable[Any]]],
right: Optional[Union[Any, Iterable[Any]]]
) -> None:
"""Create a NotEqualsSubstitution substitution."""
super().__init__(left, right)

def describe(self) -> Text:
"""Return a description of this substitution as a string."""
return f'NotEqualsSubstitution({self.left} {self.right})'

def perform(self, context: LaunchContext) -> Text:
"""Perform the substitution."""
return str(not (super().perform(context) == 'true')).lower()
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