# MIT License
#
# Copyright The SCons Foundation
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"""Variable type for enumeration Variables.
Enumeration variables allow selection of one from a specified set of values.
Usage example::
opts = Variables()
opts.Add(
EnumVariable(
'debug',
help='debug output and symbols',
default='no',
allowed_values=('yes', 'no', 'full'),
map={},
ignorecase=2,
)
)
env = Environment(variables=opts)
if env['debug'] == 'full':
...
"""
from typing import Callable, List, Optional, Tuple
import SCons.Errors
__all__ = ['EnumVariable',]
[docs]def _validator(key, val, env, vals) -> None:
"""Validate that val is in vals.
Usable as the base for :class:`EnumVariable` validators.
"""
if val not in vals:
msg = (
f"Invalid value for enum variable {key!r}: {val!r}. "
f"Valid values are: {vals}"
)
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 EnumVariable(
key,
help: str,
default: str,
allowed_values: List[str],
map: Optional[dict] = None,
ignorecase: int = 0,
) -> Tuple[str, str, str, Callable, Callable]:
"""Return a tuple describing an enumaration SCons Variable.
The input parameters describe a variable with only predefined values
allowed. The value of *ignorecase* defines the behavior of the
validator and converter: if ``0``, the validator/converter are
case-sensitive; if ``1``, the validator/converter are case-insensitive;
if ``2``, the validator/converter are case-insensitive and the
converted value will always be lower-case.
Arguments:
key: variable name, passed directly through to the return tuple.
default: default values, passed directly through to the return tuple.
help: descriptive part of the help text,
will have the allowed values automatically appended.
allowed_values: list of the allowed values for this variable.
map: optional dictionary which may be used for converting the
input value into canonical values (e.g. for aliases).
ignorecase: defines the behavior of the validator and converter.
Returns:
A tuple including an appropriate converter and validator.
The result is usable as input to :meth:`~SCons.Variables.Variables.Add`.
and :meth:`~SCons.Variables.Variables.AddVariables`.
"""
# these are all inner functions so they can access EnumVariable locals.
def validator_rcase(key, val, env):
"""Case-respecting validator."""
return _validator(key, val, env, allowed_values)
def validator_icase(key, val, env):
"""Case-ignoring validator."""
return _validator(key, val.lower(), env, allowed_values)
def converter_rcase(val):
"""Case-respecting converter."""
return map.get(val, val)
def converter_icase(val):
"""Case-ignoring converter."""
return map.get(val.lower(), val)
def converter_lcase(val):
"""Case-lowering converter."""
return map.get(val.lower(), val).lower()
if map is None:
map = {}
help = f"{help} ({'|'.join(allowed_values)})"
# define validator
if ignorecase:
validator = validator_icase
else:
validator = validator_rcase
# define converter
if ignorecase == 2:
converter = converter_lcase
elif ignorecase == 1:
converter = converter_icase
else:
converter = converter_rcase
return key, help, default, validator, converter
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