# MIT License
#
# Copyright The SCons Foundation
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"""Variable type for List Variables.
A list variable allows selecting one or more from a supplied set of
allowable values, as well as from an optional mapping of alternate names
(such as aliases and abbreviations) and the special names ``'all'`` and
``'none'``. Specified values are converted during processing into values
only from the allowable values set.
Usage example::
list_of_libs = Split('x11 gl qt ical')
opts = Variables()
opts.Add(
ListVariable(
'shared',
help='libraries to build as shared libraries',
default='all',
elems=list_of_libs,
)
)
env = Environment(variables=opts)
for lib in list_of_libs:
if lib in env['shared']:
env.SharedObject(...)
else:
env.Object(...)
"""
# Known Bug: This should behave like a Set-Type, but does not really,
# since elements can occur twice.
import collections
from typing import Callable, List, Optional, Tuple, Union
import SCons.Util
__all__ = ['ListVariable',]
[docs]
class _ListVariable(collections.UserList):
"""Internal class holding the data for a List Variable.
This is normally not directly instantiated, rather the ListVariable
converter callback "converts" string input (or the default value
if none) into an instance and stores it.
Args:
initlist: the list of actual values given.
allowedElems: the list of allowable values.
"""
def __init__(
self, initlist: Optional[list] = None, allowedElems: Optional[list] = None
) -> None:
if initlist is None:
initlist = []
if allowedElems is None:
allowedElems = []
super().__init__([_f for _f in initlist if _f])
# TODO: why sorted? don't we want to display in the order user gave?
self.allowedElems = sorted(allowedElems)
def __cmp__(self, other):
return NotImplemented
def __eq__(self, other):
return NotImplemented
def __ge__(self, other):
return NotImplemented
def __gt__(self, other):
return NotImplemented
def __le__(self, other):
return NotImplemented
def __lt__(self, other):
return NotImplemented
def __str__(self) -> str:
if not self.data:
return 'none'
self.data.sort()
if self.data == self.allowedElems:
return 'all'
return ','.join(self)
[docs]
def prepare_to_store(self):
return str(self)
[docs]
def _converter(val, allowedElems, mapdict) -> _ListVariable:
"""Callback to convert list variables into a suitable form.
The arguments *allowedElems* and *mapdict* are non-standard
for a :class:`Variables` converter: the lambda in the
:func:`ListVariable` function arranges for us to be called correctly.
Incoming values ``all`` and ``none`` are recognized and converted
into their expanded form.
"""
if val == 'none':
val = []
elif val == 'all':
val = allowedElems
else:
val = [_f for _f in val.split(',') if _f]
val = [mapdict.get(v, v) for v in val]
return _ListVariable(val, allowedElems)
[docs]
def _validator(key, val, env) -> None:
"""Callback to validate supplied value(s) for a ListVariable.
Validation means "is *val* in the allowed list"? *val* has
been subject to substitution before the validator is called. The
converter created a :class:`_ListVariable` container which is stored
in *env* after it runs; this includes the allowable elements list.
Substitution makes a string made out of the values (only),
so we need to fish the allowed elements list out of the environment
to complete the validation.
Note that since 18b45e456, whether ``subst`` has been
called is conditional on the value of the *subst* argument to
:meth:`~SCons.Variables.Variables.Add`, so we have to account for
possible different types of *val*.
Raises:
UserError: if validation failed.
.. versionadded:: 4.8.0
``_validator`` split off from :func:`_converter` with an additional
check for whether *val* has been substituted before the call.
"""
allowedElems = env[key].allowedElems
if isinstance(val, _ListVariable): # not substituted, use .data
notAllowed = [v for v in val.data if v not in allowedElems]
else: # presumably a string
notAllowed = [v for v in val.split() if v not in allowedElems]
if notAllowed:
# Converter only synthesized 'all' and 'none', they are never
# in the allowed list, so we need to add those to the error message
# (as is done for the help msg).
valid = ','.join(allowedElems + ['all', 'none'])
msg = (
f"Invalid value(s) for variable {key!r}: {','.join(notAllowed)!r}. "
f"Valid values are: {valid}"
)
raise SCons.Errors.UserError(msg) from None
# lint: W0622: Redefining built-in 'help' (redefined-builtin)
# lint: W0622: Redefining built-in 'map' (redefined-builtin)
[docs]
def ListVariable(
key,
help: str,
default: Union[str, List[str]],
names: List[str],
map: Optional[dict] = None,
validator: Optional[Callable] = None,
) -> Tuple[str, str, str, None, Callable]:
"""Return a tuple describing a list variable.
The input parameters describe a list variable, where the values
can be one or more from *names* plus the special values ``all``
and ``none``.
Arguments:
key: the name of the list variable.
help: the basic help message. Will have text appended indicating
the allowable values (not including any extra names from *map*).
default: the default value(s) for the list variable. Can be
given as string (possibly comma-separated), or as a list of strings.
``all`` or ``none`` are allowed as *default*. You can also simulate
a must-specify ListVariable by giving a *default* that is not part
of *names*, it will fail validation if not supplied.
names: the allowable values. Must be a list of strings.
map: optional dictionary to map alternative names to the ones in
*names*, providing a form of alias. The converter will make
the replacement, names from *map* are not stored and will
not appear in the help message.
validator: optional callback to validate supplied values.
The default validator is used if not specified.
Returns:
A tuple including the correct converter and validator. The
result is usable as input to :meth:`~SCons.Variables.Variables.Add`.
.. versionchanged:: 4.8.0
The validation step was split from the converter to allow for
custom validators. The *validator* keyword argument was added.
"""
if map is None:
map = {}
if validator is None:
validator = _validator
names_str = f"allowed names: {' '.join(names)}"
if SCons.Util.is_List(default):
default = ','.join(default)
help = '\n '.join(
(help, '(all|none|comma-separated list of names)', names_str))
return key, help, default, validator, lambda val: _converter(val, names, map)
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