contextmanagers

Classes

ContextManager

An abstract context manager class.

class abjad.contextmanagers.ContextManager[source]

An abstract context manager class.

Attributes Summary

__repr__

Gets repr.

Special methods

overridden __repr__() → str[source]: Gets repr.

Context managers

`FilesystemState`	Filesystem state context manager.
`ForbidUpdate`	A context manager for forbidding score updates.
`NullContextManager`	A context manager that does nothing.
`ProgressIndicator`	A context manager for printing progress indications.
`RedirectedStreams`	A context manager for capturing stdout and stderr output.
`TemporaryDirectory`	A temporary directory context manager.
`TemporaryDirectoryChange`	A context manager for temporarily changing the current working directory.
`Timer`	A timing context manager.

class abjad.contextmanagers.FilesystemState(keep=None, remove=None)[source]

Filesystem state context manager.

Attributes Summary

`__enter__`	Backs up filesystem assets.
`__exit__`	Restores filesytem assets and removes backups; also removes paths in remove list.
`keep`	Gets asset paths to restore on exit.
`remove`	Gets paths to remove on exit.

Special methods

__enter__() → FilesystemState[source]: Backs up filesystem assets.

__exit__(exg_type, exc_value, trackeback) → None[source]: Restores filesytem assets and removes backups; also removes paths in remove list.

(ContextManager).__repr__() → str: Gets repr.

Read-only properties

keep

Gets asset paths to restore on exit.

Returns tuple.

remove

Gets paths to remove on exit.

Returns tuple.

class abjad.contextmanagers.ForbidUpdate(component=None, update_on_enter=True, update_on_exit=None)[source]

A context manager for forbidding score updates.

>>> staff = abjad.Staff("c'8 d'8 ~ d'2 e'4")
>>> with abjad.ForbidUpdate(component=staff):
...     for note in staff[:]:
...         pitch_1 = note.written_pitch
...         pitch_2 = pitch_1 + abjad.NamedInterval("M3")
...         pitches = [pitch_1, pitch_2]
...         chord = abjad.Chord(pitches, note.written_duration)
...         abjad.mutate.replace(note, chord)
... 

>>> abjad.wf.wellformed(staff)
True

>>> abjad.show(staff)  

Attributes Summary

`__enter__`	Enters context manager.
`__exit__`	Exits context manager.
`component`	Gets component.
`update_on_enter`	Is true when context manager should update offsets on enter.
`update_on_exit`	Is true when context manager should update offsets on exit.

Special methods

__enter__() → ForbidUpdate[source]

Enters context manager.

REGRESSION. Indicators need to be updated after swap; context manager updates indicators before forbidding further updates:

>>> staff = abjad.Staff(r"\times 1/1 { c'4 d' }")
>>> abjad.attach(abjad.Clef("alto"), staff[0][0])
>>> container = abjad.Container()
>>> abjad.mutate.swap(staff[0], container)
>>> with abjad.ForbidUpdate(staff):
...     for note in staff[0]:
...         print(note)
...         print(abjad.get.effective(note, abjad.Clef))
... 
Note("c'4")
Clef(name='alto', hide=False)
Note("d'4")
Clef(name='alto', hide=False)

__exit__(exc_type, exc_value, traceback) → None[source]: Exits context manager.

(ContextManager).__repr__() → str: Gets repr.

Read-only properties

component

Gets component.

Set to component or none.

Returns component or none.

update_on_enter

Is true when context manager should update offsets on enter.

Set to true, false or none.

update_on_exit

Is true when context manager should update offsets on exit.

Set to true, false or none.

class abjad.contextmanagers.NullContextManager[source]

A context manager that does nothing.

Attributes Summary

`__enter__`	Enters context manager and does nothing.
`__exit__`	Exits context manager and does nothing.

Special methods

__enter__() → None[source]: Enters context manager and does nothing.

__exit__(exc_type, exc_value, traceback) → None[source]: Exits context manager and does nothing.

(ContextManager).__repr__() → str: Gets repr.

class abjad.contextmanagers.ProgressIndicator(message='', total=None, verbose=True, is_warning=None)[source]

A context manager for printing progress indications.

Attributes Summary

`END`
`RED`
`__enter__`	Enters progress indicator.
`__exit__`	Exits progress indicator.
`__repr__`	Gets interpreter representation of context manager.
`advance`	Advances the progress indicator's progress count.
`is_warning`	Is true if progress indicator prints in red when its progress goes above zero.
`message`	Gets message of progress indicator.
`progress`	Gets progress.
`total`	Gets total count.
`verbose`	Is true if progress indicator prints status.

Special methods

__enter__() → ProgressIndicator[source]: Enters progress indicator.

__exit__(exc_type, exc_value, traceback) → None[source]: Exits progress indicator.

overridden __repr__() → str[source]

Gets interpreter representation of context manager.

>>> context_manager = abjad.ProgressIndicator()
>>> context_manager
<ProgressIndicator()>

Methods

advance()[source]: Advances the progress indicator’s progress count. Overwrites the current terminal line with the progress indicators message and new count.

Read-only properties

is_warning: Is true if progress indicator prints in red when its progress goes above zero.

message: Gets message of progress indicator.

progress: Gets progress.

total: Gets total count.

verbose: Is true if progress indicator prints status.

class abjad.contextmanagers.RedirectedStreams(stdout=None, stderr=None)[source]

A context manager for capturing stdout and stderr output.

>>> abjad.RedirectedStreams()
<RedirectedStreams()>

>>> from io import StringIO
>>> string_io = StringIO()
>>> with abjad.RedirectedStreams(stdout=string_io):
...     print("hello, world!")
... 
>>> result = string_io.getvalue()
>>> string_io.close()
>>> print(result)
hello, world!

Attributes Summary

`__enter__`	Enters redirected streams context manager.
`__exit__`	Exits redirected streams context manager.
`__repr__`	Gets interpreter representation of context manager.
`stderr`	Gets stderr of context manager.
`stdout`	Gets stdout of context manager.

Special methods

__enter__() → RedirectedStreams[source]: Enters redirected streams context manager.

__exit__(exc_type, exc_value, traceback) → None[source]: Exits redirected streams context manager.

overridden __repr__() → str[source]

Gets interpreter representation of context manager.

>>> context_manager = abjad.RedirectedStreams()
>>> context_manager
<RedirectedStreams()>

Read-only properties

stderr: Gets stderr of context manager.

stdout: Gets stdout of context manager.

class abjad.contextmanagers.TemporaryDirectory(parent_directory=None)[source]

A temporary directory context manager.

Attributes Summary

`__enter__`	Enters context manager.
`__exit__`	Exits context manager.
`parent_directory`	Gets parent directory.
`temporary_directory`	Gets temporary directory.

Special methods

__enter__()[source]

Enters context manager.

Creates and returns path to a temporary directory.

__exit__(exc_type, exc_value, traceback) → None[source]

Exits context manager.

Deletes previously created temporary directory.

(ContextManager).__repr__() → str: Gets repr.

Read-only properties

parent_directory: Gets parent directory.

temporary_directory: Gets temporary directory.

class abjad.contextmanagers.TemporaryDirectoryChange(directory=None, verbose=None)[source]

A context manager for temporarily changing the current working directory.

Attributes Summary

`__enter__`	Enters context manager and changes to `directory`.
`__exit__`	Exits context manager and returns to original working directory.
`__repr__`	Gets interpreter representation of context manager.
`directory`	Gets temporary directory of context manager.
`original_directory`	Gets original directory of context manager.
`verbose`	Is true if context manager prints verbose messages on entrance and exit.

Special methods

__enter__() → TemporaryDirectoryChange[source]: Enters context manager and changes to directory.

__exit__(exc_type, exc_value, traceback) → None[source]: Exits context manager and returns to original working directory.

overridden __repr__() → str[source]: Gets interpreter representation of context manager.

Read-only properties

directory: Gets temporary directory of context manager.

original_directory: Gets original directory of context manager.

verbose: Is true if context manager prints verbose messages on entrance and exit.

class abjad.contextmanagers.Timer(exit_message=None, enter_message=None, print_continuously_from_background=False, verbose=True)[source]

A timing context manager.

>>> timer = abjad.Timer()
>>> with timer:
...     for _ in range(1000000):
...         x = 1 + 1
... 
>>> timer.elapsed_time  
0.02991938591003418

The timer can also be accessed from within the with block:

>>> with abjad.Timer() as timer:  
...     for _ in range(5):
...         for _ in range(1000000):
...             x = 1 + 1
...         print(timer.elapsed_time)
... 
0.029968976974487305
0.05989813804626465
0.09048700332641602
0.12091708183288574
0.15134000778198242

Timers can be reused between with blocks. They will reset their clock on entering any with block.

Attributes Summary

`__enter__`	Enters context manager.
`__exit__`	Exit context manager.
`elapsed_time`	Elapsed time.
`enter_message`	Timer enter message.
`exit_message`	Timer exit message.
`print_continuously_from_background`	Is true when timer should print continuously from background.
`start_time`	Start time of timer.
`stop_time`	Stop time of timer.
`total_time_message`	Gets total time message.
`verbose`	Is true if timer should print messages.

Special methods

__enter__() → Timer[source]: Enters context manager.

__exit__(exc_type, exc_value, traceback) → None[source]: Exit context manager.

(ContextManager).__repr__() → str: Gets repr.

Read-only properties

elapsed_time: Elapsed time.

enter_message: Timer enter message.

exit_message: Timer exit message.

print_continuously_from_background: Is true when timer should print continuously from background.

start_time

Start time of timer.

Returns time.

stop_time

Stop time of timer.

Returns time.

total_time_message

Gets total time message.

Truncated to the nearest second.

verbose: Is true if timer should print messages.