`cloup.constraints`¶

Constraints for parameter groups.

Added in version v0.5.0.

Submodules¶

Classes¶

`If`(condition, then[, else_])	Checks one constraint or another depending on the truth value of the condition.
`AcceptAtMost`(n)	Satisfied if the number of set parameters is <= n.
`AcceptBetween`(min, max)	Satisfied if the number of set parameters is between `min` and `max` (included).
`And`(*constraints)	It's satisfied if all operands are satisfied.
`Constraint`()	A constraint that can be checked against an arbitrary collection of CLI parameters with respect to a specific `click.Context` (which contains the values assigned to the parameters in `ctx.params`).
`ErrorFmt`()	`Rephraser` allows you to pass a `format` string as `error` argument; this class contains the "replacement fields" supported by such format string. You can use them as following::.
`Operator`(*constraints)	Base class for all n-ary operators defined on constraints.
`Or`(*constraints)	It's satisfied if at least one of the operands is satisfied.
`Rephraser`(constraint[, help, error])	A constraint decorator that can override the help and/or the error message of the wrapped constraint.
`RequireAtLeast`(n)	Satisfied if the number of set parameters is >= n.
`RequireExactly`(n)	Requires an exact number of parameters to be set.
`WrapperConstraint`(constraint, **attrs)	Abstract class that wraps another constraint and delegates all methods to it.
`BoundConstraintSpec`(constraint, param_names)	A NamedTuple storing a `Constraint` and the names of the parameters it has to check.
`ConstraintMixin`(*args[, constraints, ...])	Provides support for constraints.
`AllSet`(*param_names)	True if all listed parameters are set.
`AnySet`(*param_names)	True if any of the listed parameters is set.
`Equal`(param_name, value)	True if the parameter value equals `value`.
`IsSet`(param_name)	True if the parameter is set.
`Not`(predicate)	Logical NOT of a predicate.

Functions¶

`constrained_params`(constr, *param_adders)	Return a decorator that adds the given parameters and applies a constraint to them. Equivalent to::.
`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`).

Attributes¶

`ErrorRephraser`
`HelpRephraser`
`accept_none`	Satisfied if none of the parameters is set. Useful only in conditional constraints.
`all_or_none`	Satisfied if either all or none of the parameters are set.
`mutually_exclusive`	Satisfied if at most one of the parameters is set.
`require_all`	Satisfied if all parameters are set.
`require_any`	Alias for `RequireAtLeast(1)`.
`require_one`	Alias for `RequireExactly(1)`.

Contents¶

class cloup.constraints.If(condition, then, else_=None)[source]¶

Bases: cloup.constraints._core.Constraint

Checks one constraint or another depending on the truth value of the condition.

Added in version 0.8.0: you can now pass a sequence of parameter names as condition, which corresponds to the predicate AllSet(*param_names).

Parameters:

condition (str | Sequence[str] | Predicate) – can be either an instance of Predicate or (more often) the name of a parameter or a list/tuple of parameters that must be all set for the condition to be true.
then (Constraint) – a constraint checked if the condition is true.
else – an (optional) constraint checked if the condition is false.
else_ (Constraint | None)

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

class cloup.constraints.AcceptAtMost(n)[source]¶

Bases: Constraint

Satisfied if the number of set parameters is <= n.

Parameters:: n (int)

max_num_params¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

class cloup.constraints.AcceptBetween(min, max)[source]¶

Bases: WrapperConstraint

Abstract class that wraps another constraint and delegates all methods to it. Useful when you want to define a parametric constraint combining other existing constraints minimizing the boilerplate.

This is an alternative to defining a function and using Rephraser. Feel free to do that in your code, but cloup will stick to the convention that parametric constraints are defined as classes and written in camel-case.

Satisfied if the number of set parameters is between min and max (included).

Parameters:

min (int) – must be an integer >= 0
max (int) – must be an integer > min

min_num_params¶

max_num_params¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

class cloup.constraints.And(*constraints)[source]¶

Bases: Operator

It’s satisfied if all operands are satisfied.

N-ary operator for constraints. :param constraints: operands

Parameters:: constraints (Constraint)

HELP_SEP = ' and '¶: Used as separator of all constraints’ help strings.

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__and__(other)[source]¶

Parameters:: other (Constraint)
Return type:: And

class cloup.constraints.Constraint[source]¶

Bases: abc.ABC

A constraint that can be checked against an arbitrary collection of CLI parameters with respect to a specific click.Context (which contains the values assigned to the parameters in ctx.params).

Changed in version 0.9.0: calling a constraint, previously equivalent to check(), is now equivalent to calling cloup.constrained_params() with this constraint as first argument.

static must_check_consistency(ctx)[source]¶

Return True if consistency checks are enabled.

Changed in version 0.9.0: this method now a static method and takes a click.Context in input.

Parameters:: ctx (click.Context)
Return type:: bool

__getattr__(attr)[source]¶

Parameters:: attr (str)
Return type:: Any

abstract help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

abstract check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

check(params: Sequence[click.Parameter], ctx: click.Context | None = None) → None[source]¶

check(params: Sequence[str], ctx: click.Context | None = None) → None

Raise an exception if the constraint is not satisfied by the input parameters in the given (or current) context.

This method calls both check_consistency() (if enabled) and check_values().

Tip

By default check_consistency() is called since it shouldn’t have any performance impact. Nonetheless, you can disable it in production passing check_constraints_consistency=False as part of your context_settings.

Parameters:

params – an iterable of parameter names or a sequence of click.Parameter
ctx – a click.Context; if not provided, click.get_current_context() is used

Raises:

ConstraintViolated UnsatisfiableConstraint

rephrased(help=None, error=None)[source]¶

Override the help string and/or the error message of this constraint wrapping it with a Rephraser.

Parameters:

help (Union[None, str, HelpRephraser]) – if provided, overrides the help string of this constraint. It can be a string or a function (ctx: click.Context, constr: Constraint) -> str. If you want to hide this constraint from the help, pass help="".
error (Union[None, str, ErrorRephraser]) –
if provided, overrides the error message of this constraint. It can be:
- a string, eventually a format string supporting the replacement fields described in ErrorFmt.
- or a function (err: ConstraintViolated) -> str; note that a ConstraintViolated error has fields for ctx, constraint and params, so it’s a complete description of what happened.

Return type:

Rephraser

hidden()[source]¶

Hide this constraint from the command help.

Return type:: Rephraser

__call__(*param_adders)[source]¶

Equivalent to calling cloup.constrained_params() with this constraint as first argument.

Changed in version 0.9.0: this method, previously equivalent to check(), is now equivalent to calling cloup.constrained_params() with this constraint as first argument.

Parameters:: param_adders (cloup.typing.Decorator)
Return type:: Callable[[cloup.typing.F], cloup.typing.F]

__or__(other)[source]¶

Parameters:: other (Constraint)
Return type:: Or

__and__(other)[source]¶

Parameters:: other (Constraint)
Return type:: And

__repr__()[source]¶

Return type:: str

class cloup.constraints.ErrorFmt[source]¶

Bases: cloup._util.FrozenSpace

Rephraser allows you to pass a format string as error argument; this class contains the “replacement fields” supported by such format string. You can use them as following:

mutually_exclusive.rephrased(
    error=f"{ErrorFmt.error}\n"
          f"Some extra information here."
)

error = '{error}'¶: Replaced by the original error message. Useful if all you want is to append or prepend some extra info to the original error message.

param_list = '{param_list}'¶: Replaced by a 2-space indented list of the constrained parameters.

cloup.constraints.ErrorRephraser¶

cloup.constraints.HelpRephraser¶

class cloup.constraints.Operator(*constraints)[source]¶

Bases: Constraint, abc.ABC

Base class for all n-ary operators defined on constraints.

N-ary operator for constraints. :param constraints: operands

Parameters:: constraints (Constraint)

HELP_SEP: str¶: Used as separator of all constraints’ help strings.

constraints¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

__repr__()[source]¶

Return type:: str

class cloup.constraints.Or(*constraints)[source]¶

Bases: Operator

It’s satisfied if at least one of the operands is satisfied.

N-ary operator for constraints. :param constraints: operands

Parameters:: constraints (Constraint)

HELP_SEP = ' or '¶: Used as separator of all constraints’ help strings.

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__or__(other)[source]¶

Parameters:: other (Constraint)
Return type:: Or

class cloup.constraints.Rephraser(constraint, help=None, error=None)[source]¶

Bases: Constraint

A constraint decorator that can override the help and/or the error message of the wrapped constraint.

You’ll rarely (if ever) use this class directly. In most cases, you’ll use the method Constraint.rephrased(). Refer to it for more info.

See also

Constraint.rephrased() – wraps a constraint with a Rephraser.
WrapperConstraint – alternative to Rephraser.
ErrorFmt – describes the keyword you can use in an error format string.

Parameters:

constraint (Constraint)
help (None | str | Callable[[Context, Constraint], str])
error (None | str | Callable[[ConstraintViolated], str])

constraint¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

class cloup.constraints.RequireAtLeast(n)[source]¶

Bases: Constraint

Satisfied if the number of set parameters is >= n.

Parameters:: n (int)

min_num_params¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

class cloup.constraints.RequireExactly(n)[source]¶

Bases: WrapperConstraint

Requires an exact number of parameters to be set.

Parameters:

constraint – the constraint to wrap
attrs – these are just used to generate a __repr__ method
n (int)

num_params¶

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

class cloup.constraints.WrapperConstraint(constraint, **attrs)[source]¶

Bases: Constraint

Abstract class that wraps another constraint and delegates all methods to it. Useful when you want to define a parametric constraint combining other existing constraints minimizing the boilerplate.

Parameters:

constraint (Constraint) – the constraint to wrap
attrs (Any) – these are just used to generate a __repr__ method

help(ctx)[source]¶

A description of the constraint.

Parameters:: ctx (click.Context)
Return type:: str

check_consistency(params)[source]¶

Perform some sanity checks that detect inconsistencies between these constraints and the properties of the input parameters (e.g. required).

For example, a constraint that requires the parameters to be mutually exclusive is not consistent with a group of parameters with multiple required options.

These sanity checks are meant to catch developer’s mistakes and don’t depend on the values assigned to the parameters; therefore:

they can be performed before any parameter parsing
they can be disabled in production (setting check_constraints_consistency=False in context_settings)

Parameters:: params (Sequence[click.Parameter]) – list of click.Parameter instances
Raises:: UnsatisfiableConstraint if the constraint cannot be satisfied independently from the values provided by the user
Return type:: None

check_values(params, ctx)[source]¶

Check that the constraint is satisfied by the input parameters in the given context, which (among other things) contains the values assigned to the parameters in ctx.params.

You probably don’t want to call this method directly. Use check() instead.

Parameters:

params (Sequence[click.Parameter]) – list of click.Parameter instances
ctx (click.Context) – click.Context

Raises:

ConstraintViolated

Return type:

None

__repr__()[source]¶

Return type:: str

cloup.constraints.accept_none¶: Satisfied if none of the parameters is set. Useful only in conditional constraints.

cloup.constraints.all_or_none¶: Satisfied if either all or none of the parameters are set.

cloup.constraints.mutually_exclusive¶: Satisfied if at most one of the parameters is set.

cloup.constraints.require_all¶: Satisfied if all parameters are set.

cloup.constraints.require_any¶: Alias for RequireAtLeast(1).

cloup.constraints.require_one¶: Alias for RequireExactly(1).

class cloup.constraints.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: Sequence[str]¶

resolve_params(cmd)[source]¶

Parameters:: cmd (ConstraintMixin)
Return type:: BoundConstraint

class cloup.constraints.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

show_constraints¶

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:

ctx (click.Context)
formatter (cloup.HelpFormatter)

Return type:

None

must_show_constraints(ctx)[source]¶

Parameters:: ctx (click.Context)
Return type:: bool

cloup.constraints.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.

Added 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]

cloup.constraints.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]

class cloup.constraints.AllSet(*param_names)[source]¶

Bases: Predicate

True if all listed parameters are set.

Added in version 0.8.0.

Parameters:: param_names (str)

param_names¶

negated_description(ctx)[source]¶

Succinct description of the negation of this predicate (alias: neg_desc).

Parameters:: ctx (click.Context)
Return type:: str

description(ctx)[source]¶

Succinct description of the predicate (alias: desc).

Parameters:: ctx (click.Context)
Return type:: str

__call__(ctx)[source]¶

Evaluate the predicate on the given context.

Parameters:: ctx (click.Context)
Return type:: bool

__and__(other)[source]¶

Parameters:: other (Predicate)
Return type:: Predicate

class cloup.constraints.AnySet(*param_names)[source]¶

Bases: Predicate

True if any of the listed parameters is set.

Added in version 0.8.0.

Parameters:: param_names (str)

param_names¶

negated_description(ctx)[source]¶

Succinct description of the negation of this predicate (alias: neg_desc).

Parameters:: ctx (click.Context)
Return type:: str

description(ctx)[source]¶

Succinct description of the predicate (alias: desc).

Parameters:: ctx (click.Context)
Return type:: str

__call__(ctx)[source]¶

Evaluate the predicate on the given context.

Parameters:: ctx (click.Context)
Return type:: bool

__or__(other)[source]¶

Parameters:: other (Predicate)
Return type:: Predicate

class cloup.constraints.Equal(param_name, value)[source]¶

Bases: Predicate

True if the parameter value equals value.

Parameters:

param_name (str)
value (Any)

param_name¶

value¶

description(ctx)[source]¶

Succinct description of the predicate (alias: desc).

Parameters:: ctx (click.Context)
Return type:: str

negated_description(ctx)[source]¶

Succinct description of the negation of this predicate (alias: neg_desc).

Parameters:: ctx (click.Context)
Return type:: str

__call__(ctx)[source]¶

Evaluate the predicate on the given context.

Parameters:: ctx (click.Context)
Return type:: bool

class cloup.constraints.IsSet(param_name)[source]¶

Bases: Predicate

True if the parameter is set.

Parameters:: param_name (str)

param_name¶

description(ctx)[source]¶

Succinct description of the predicate (alias: desc).

Parameters:: ctx (click.Context)
Return type:: str

negated_description(ctx)[source]¶

Succinct description of the negation of this predicate (alias: neg_desc).

Parameters:: ctx (click.Context)
Return type:: str

__call__(ctx)[source]¶

Evaluate the predicate on the given context.

Parameters:: ctx (click.Context)
Return type:: bool

__and__(other)[source]¶

Parameters:: other (Predicate)
Return type:: Predicate

__or__(other)[source]¶

Parameters:: other (Predicate)
Return type:: Predicate

class cloup.constraints.Not(predicate)[source]¶

Bases: Predicate, Generic[P]

Logical NOT of a predicate.

Parameters:: predicate (P)

predicate¶

description(ctx)[source]¶

Succinct description of the predicate (alias: desc).

Parameters:: ctx (click.Context)
Return type:: str

negated_description(ctx)[source]¶

Succinct description of the negation of this predicate (alias: neg_desc).

Parameters:: ctx (click.Context)
Return type:: str

__call__(ctx)[source]¶

Evaluate the predicate on the given context.

Parameters:: ctx (click.Context)
Return type:: bool

__invert__()[source]¶

Return type:: P

__repr__()[source]¶

Return type:: str

exception cloup.constraints.ConstraintViolated(message, ctx, constraint, params)[source]¶

Bases: click.UsageError

An internal exception that signals a usage error. This typically aborts any further handling.

Parameters:

message (str) – the error message to display.
ctx (click.Context) – optionally the context that caused this error. Click will fill in the context automatically in some situations.
constraint (cloup.constraints._core.Constraint)
params (Sequence[click.Parameter])

Initialize self. See help(type(self)) for accurate signature.

ctx¶

constraint¶

params¶

classmethod default(desc, ctx, constraint, params)[source]¶

Parameters:

desc (str)
ctx (click.Context)
constraint (cloup.constraints._core.Constraint)
params (Sequence[click.Parameter])

Return type:

ConstraintViolated

exception cloup.constraints.UnsatisfiableConstraint(constraint, params, reason)[source]¶

Bases: Exception

Raised if a constraint cannot be satisfied by a group of parameters independently from their values at runtime; e.g. mutually_exclusive cannot be satisfied if multiple of the parameters are required.

Initialize self. See help(type(self)) for accurate signature.

Parameters:

constraint (cloup.constraints._core.Constraint)
params (Iterable[click.Parameter])
reason (str)

constraint¶

params¶

reason¶

cloup.constraints¶

Submodules¶

Classes¶

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`cloup.constraints`¶