pytilities.overloading.parameter

pytilities.overloading.parameter.Param

alias of Parameter

class pytilities.overloading.parameter.Parameter(name, *args, **kwargs)

A parameter of an operation.

It can match arguments and provide default values for them.

Note that an argument matches a parameter, if its matcher returns True on the argument value or the parameter has a default.

__init__(name, *args, **kwargs)

Construct a Parameter.

Parameters:

• name (string) – name of parameter as specified in keyword arguments
• kwargs –

  Keyword parameters:

  • type_ or types or matcher:

    type_: type of the parameter types: iterable of possible types for the parameter matcher: a matcher function of type f(value) -> matched::bool

    If given as first positional arg, type_ is assumed. If not given, will match any value.

  • default:

    default value for the parameter. Omit if param has no default

    Can also be given as second positional arg.

Preconditions :

1. default must match the specified matcher

__str__()

read_arg(arg)

Read/process the given arg.

Parameters:

• arg – the argument value to read

Returns:

True if parameter matches arg

Return type:

bool

read_kwargs(kwargs)

Look in a dict for a matching arg and process its value.

Parameters:

• kwargs – frozen dictionary of arguments

Returns:

True if a matching argument was found in kwargs

Return type:

bool

write(kwargs)

Adds the last read argument value to a dictionary.

Parameters:

• kwargs – the dictionary to add the last value and the parameter name to

Preconditions :

1. the parameter matched on the last read

__weakref__

list of weak references to the object (if defined)

_matched

name