pathex.managing.trace_checker module

class TraceChecker(expression: Expression, machine: DecomposerMatch | None = None)

Bases: pathex.managing.manager.Manager

This class is just to demonstrate the use of manager for other tasks different than task synchronization.

>>> from pathex import Tag
>>> a, b, c = Tag.named('func_a', 'func_b', 'func_c')
>>> trace_checker = TraceChecker((a+b+c)*...)

>>> @trace_checker.region(a)
... def func_a():
...     return 'func_a'

>>> @trace_checker.region(b)
... def func_b():
...     return 'func_b'

>>> @trace_checker.region(c)
... def func_c():
...     return 'func_c'

>>> func_b(), func_a(), func_c()
Traceback (most recent call last):
    ...
AssertionError: func_b.enter is not allowed as first label

>>> func_a(), func_b(), func_c()
('func_a', 'func_b', 'func_c')

>>> func_a(), func_c(), func_b()
Traceback (most recent call last):
    ...
AssertionError: func_c.enter is not allowed after func_a.exit

>>> func_b(), func_c()
('func_b', 'func_c')

match(label: object) → object

This method is used to notify to the manager the presence of a given label.

The manager then see if this label is allowed by checking if the internal expression can generate the given label. If the label is allowed or not, a respective action is taken.

Parameters

label (Hashable) – The label to check for.