cloup.constraints._support#

Classes#

BoundConstraintSpec(constraint, param_names)

A NamedTuple storing a Constraint and the names of the parameters it has to check.

BoundConstraint(constraint, params)

Internal utility NamedTuple that represents a Constraint bound to a collection of click.Parameter instances.

ConstraintMixin(*args[, constraints, ...])

Provides support for constraints.

Functions#

constraint(constr, params)

Register a constraint on a list of parameters specified by (destination) name (e.g. the default name of --input-file is input_file).

constrained_params(constr, *param_adders)

Return a decorator that adds the given parameters and applies a constraint to them. Equivalent to::.

ensure_constraints_support(command)

Contents#

class cloup.constraints._support.BoundConstraintSpec[source]#

Bases: NamedTuple

A NamedTuple storing a Constraint and the names of the parameters it has to check.

Parameters:

  • constraint (Constraint) –

  • param_names (Sequence[str]) –

constraint :cloup.constraints._core.Constraint#
param_names :Union[Sequence[str]]#
resolve_params(cmd)[source]#
Parameters:

cmd (ConstraintMixin) –

Return type:

BoundConstraint

cloup.constraints._support.constraint(constr, params)[source]#

Register a constraint on a list of parameters specified by (destination) name (e.g. the default name of --input-file is input_file).

Parameters:

  • constr (Constraint) –

  • params (Iterable[str]) –

Return type:

Callable[[F], F]

cloup.constraints._support.constrained_params(constr, *param_adders)[source]#

Return a decorator that adds the given parameters and applies a constraint to them. Equivalent to:

@param_adders[0]
...
@param_adders[-1]
@constraint(constr, <param names>)

This decorator saves you to manually (re)type the parameter names. It can also be used inside @option_group.

Instead of using this decorator, you can also call the constraint itself:

@constr(*param_adders)

but remember that:

  • Python 3.9 is the first that allows arbitrary expressions on the right of @;

  • using a long conditional/composite constraint as decorator may be less readable.

In these cases, you may consider using @constrained_params.

New in version 0.9.0.

Parameters:

  • constr (Constraint) – an instance of Constraint

  • param_adders (Callable[[Callable[[...], Any]], Callable[[...], Any]]) – function decorators, each attaching a single parameter to the decorated function.

Return type:

Callable[[F], F]

class cloup.constraints._support.BoundConstraint[source]#

Bases: NamedTuple

Internal utility NamedTuple that represents a Constraint bound to a collection of click.Parameter instances. Note: this is not a subclass of Constraint.

Parameters:

  • constraint (Constraint) –

  • params (Sequence[Parameter]) –

constraint :cloup.constraints._core.Constraint#
params :Sequence[click.Parameter]#
check_consistency()[source]#
Return type:

None

check_values(ctx)[source]#
Parameters:

ctx (click.Context) –

Return type:

None

get_help_record(ctx)[source]#
Parameters:

ctx (click.Context) –

Return type:

Optional[Tuple[str, str]]

class cloup.constraints._support.ConstraintMixin(*args, constraints=(), show_constraints=None, **kwargs)[source]#

Provides support for constraints.

Parameters:

  • constraints (Sequence[BoundConstraintSpec | BoundConstraint]) – sequence of constraints bound to specific groups of parameters. Note that constraints applied to option groups are collected from the option groups themselves, so they don’t need to be included in this argument.

  • show_constraints (bool | None) – whether to include a “Constraint” section in the command help. This is also available as a context setting having a lower priority than this attribute.

  • args (Any) – positional arguments forwarded to the next class in the MRO

  • kwargs (Any) – keyword arguments forwarded to the next class in the MRO

optgroup_constraints#

Constraints applied to OptionGroup instances.

param_constraints :Tuple[BoundConstraint, Ellipsis]#

Constraints registered using @constraint (or equivalent method).

all_constraints#

All constraints applied to parameter/option groups of this command.

parse_args(ctx, args)[source]#
Parameters:

  • ctx (click.Context) –

  • args (List[str]) –

Return type:

List[str]

get_param_by_name(name)[source]#
Parameters:

name (str) –

Return type:

click.Parameter

get_params_by_name(names)[source]#
Parameters:

names (Iterable[str]) –

Return type:

Sequence[click.Parameter]

format_constraints(ctx, formatter)[source]#
Parameters:
Return type:

None

must_show_constraints(ctx)[source]#
Parameters:

ctx (click.Context) –

Return type:

bool

cloup.constraints._support.ensure_constraints_support(command)[source]#
Parameters:

command (Command) –

Return type:

ConstraintMixin