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# core.prefilter

## Module: `core.prefilter`

Inheritance diagram for `IPython.core.prefilter`:

Prefiltering components.

Prefilters transform user input before it is exec’d by Python. These transforms are used to implement additional syntax such as !ls and %magic.

Authors:

- Brian Granger
- Fernando Perez
- Dan Milstein
- Ville Vainio

## Classes

### `AliasChecker`

class `IPython.core.prefilter.``AliasChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Check if the initital identifier on the line is an alias.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `AliasHandler`

class `IPython.core.prefilter.``AliasHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Handle alias input lines.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `AssignMagicTransformer`

class `IPython.core.prefilter.``AssignMagicTransformer`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterTransformer`

  Handle the a = %who syntax.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform`(line, continue_prompt)

### `AssignSystemTransformer`

class `IPython.core.prefilter.``AssignSystemTransformer`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterTransformer`

  Handle the files = !ls syntax.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform`(line, continue_prompt)

### `AssignmentChecker`

class `IPython.core.prefilter.``AssignmentChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Check to see if user is assigning to a var for the first time, in which case we want to avoid any sort of automagic / autocall games.

    This allows users to assign to either alias or magic names true python variables (the magic/alias systems always take second seat to true python code). E.g. ls=’hi’, or ls,that=1,2

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `AutoHandler`

class `IPython.core.prefilter.``AutoHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Handle lines which can be auto-executed, quoting if requested.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `AutoMagicChecker`

class `IPython.core.prefilter.``AutoMagicChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    If the ifun is magic, and automagic is on, run it. Note: normal, non-auto magic would already have been triggered via ‘%’ in check_esc_chars. This just checks for automagic. Also, before triggering the magic handler, make sure that there is nothing in the user namespace which could shadow it.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `AutocallChecker`

class `IPython.core.prefilter.``AutocallChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Check if the initial word/function is callable and autocall is on.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `EmacsChecker`

class `IPython.core.prefilter.``EmacsChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Emacs ipython-mode tags certain input lines.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `EmacsHandler`

class `IPython.core.prefilter.``EmacsHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Handle input lines marked by python-mode.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `EscCharsChecker`

class `IPython.core.prefilter.``EscCharsChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Check for escape character and return either a handler to handle it, or None if there is no escape char.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `HelpHandler`

class `IPython.core.prefilter.``HelpHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Try to get some help for the object.

    obj? or ?obj -> basic information. obj?? or ??obj -> more details.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `IPyAutocallChecker`

class `IPython.core.prefilter.``IPyAutocallChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Instances of IPyAutocall in user_ns get autocalled immediately

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `IPyPromptTransformer`

class `IPython.core.prefilter.``IPyPromptTransformer`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterTransformer`

  Handle inputs that start classic IPython prompt syntax.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform`(line, continue_prompt)

### `LineInfo`

class `IPython.core.prefilter.``LineInfo`(line, continue_prompt)

  Bases: `object`

  A single line of input and associated info.

  Includes the following as properties:

  line
    The original, raw line
  continue_prompt
    Is this line a continuation in a sequence of multiline input?
  pre
    The initial esc character or whitespace.
  pre_char
    The escape character(s) in pre or the empty string if there isn’t one. Note that ‘!!’ is a possible value for pre_char. Otherwise it will always be a single character.
  pre_whitespace
    The leading whitespace from pre if it exists. If there is a pre_char, this is just ‘’.
  ifun
    The ‘function part’, which is basically the maximal initial sequence of valid python identifiers and the ‘.’ character. This is what is checked for alias and magic transformations, used for auto-calling, etc.
  the_rest
    Everything else on the line.
  `__init__`(line, continue_prompt)
  `ofind`(ip)

    Do a full, attribute-walking lookup of the ifun in the various namespaces for the given IPython InteractiveShell instance.

    Return a dict with keys: found,obj,ospace,ismagic

    Note: can cause state changes because of calling getattr, but should only be run if autocall is on and if the line hasn’t matched any other, less dangerous handlers.

    Does cache the results of the call, so can be called multiple times without worrying about further damaging state.

### `MacroChecker`

class `IPython.core.prefilter.``MacroChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `MacroHandler`

class `IPython.core.prefilter.``MacroHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)
  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `MagicHandler`

class `IPython.core.prefilter.``MagicHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Execute magic functions.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `MultiLineMagicChecker`

class `IPython.core.prefilter.``MultiLineMagicChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Allow ! and !! in multi-line statements if multi_line_specials is on

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `PrefilterChecker`

class `IPython.core.prefilter.``PrefilterChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.config.configurable.Configurable`

  Inspect an input line and return a handler for that line.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    Inspect line_info and return a handler instance or None.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `PrefilterError`

class `IPython.core.prefilter.``PrefilterError`

  Bases: `exceptions.Exception`

  `__init__`()

    x.__init__(...) initializes x; see x.__class__.__doc__ for signature

  `args`
  `message`

### `PrefilterHandler`

class `IPython.core.prefilter.``PrefilterHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.config.configurable.Configurable`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Handle normal input lines. Use as a template for handlers.

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `PrefilterManager`

class `IPython.core.prefilter.``PrefilterManager`(shell=None, config=None)

  Bases: `IPython.config.configurable.Configurable`

  Main prefilter component.

  The IPython prefilter is run on all user input before it is run. The prefilter consumes lines of input and produces transformed lines of input.

  The iplementation consists of two phases:

  1. Transformers
  2. Checkers and handlers

  Over time, we plan on deprecating the checkers and handlers and doing everything in the transformers.

  The transformers are instances of `PrefilterTransformer` and have a single method `transform()` that takes a line and returns a transformed line. The transformation can be accomplished using any tool, but our current ones use regular expressions for speed. We also ship `pyparsing` in `IPython.external` for use in transformers.

  After all the transformers have been run, the line is fed to the checkers, which are instances of `PrefilterChecker`. The line is passed to the `check()` method, which either returns None or a `PrefilterHandler` instance. If None is returned, the other checkers are tried. If an `PrefilterHandler` instance is returned, the line is passed to the `handle()` method of the returned handler and no further checkers are tried.

  Both transformers and checkers have a priority attribute, that determines the order in which they are called. Smaller priorities are tried first.

  Both transformers and checkers also have enabled attribute, which is a boolean that determines if the instance is used.

  Users or developers can change the priority or enabled attribute of transformers or checkers, but they must call the `sort_checkers()` or `sort_transformers()` method after changing the priority.

  `__init__`(shell=None, config=None)
  `checkers`

    Return a list of checkers, sorted by priority.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `find_handler`(line_info)

    Find a handler for the line_info by trying checkers.

  `get_handler_by_esc`(esc_str)

    Get a handler by its escape string.

  `get_handler_by_name`(name)

    Get a handler by its name.

  `handlers`

    Return a dict of all the handlers.

  `init_checkers`()

    Create the default checkers.

  `init_handlers`()

    Create the default handlers.

  `init_transformers`()

    Create the default transformers.

  `multi_line_specials`

    A casting version of the boolean trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_line`(line, continue_prompt=False)

    Prefilter a single input line as text.

    This method prefilters a single line of text by calling the transformers and then the checkers/handlers.

  `prefilter_line_info`(line_info)

    Prefilter a line that has been converted to a LineInfo object.

    This implements the checker/handler part of the prefilter pipe.

  `prefilter_lines`(lines, continue_prompt=False)

    Prefilter multiple input lines of text.

    This is the main entry point for prefiltering multiple lines of input. This simply calls `prefilter_line()` for each line of input.

    This covers cases where there are multiple lines in the user entry, which is the case when the user goes back to a multiline history entry and presses enter.

  `register_checker`(checker)

    Register a checker instance.

  `register_handler`(name, handler, esc_strings)

    Register a handler instance by name with esc_strings.

  `register_transformer`(transformer)

    Register a transformer instance.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `sort_checkers`()

    Sort the checkers by priority.

    This must be called after the priority of a checker is changed. The `register_checker()` method calls this automatically.

  `sort_transformers`()

    Sort the transformers by priority.

    This must be called after the priority of a transformer is changed. The `register_transformer()` method calls this automatically.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform_line`(line, continue_prompt)

    Calls the enabled transformers in order of increasing priority.

  `transformers`

    Return a list of checkers, sorted by priority.

  `unregister_checker`(checker)

    Unregister a checker instance.

  `unregister_handler`(name, handler, esc_strings)

    Unregister a handler instance by name with esc_strings.

  `unregister_transformer`(transformer)

    Unregister a transformer instance.

### `PrefilterTransformer`

class `IPython.core.prefilter.``PrefilterTransformer`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.config.configurable.Configurable`

  Transform a line of user input.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform`(line, continue_prompt)

    Transform a line, returning the new one.

### `PyPromptTransformer`

class `IPython.core.prefilter.``PyPromptTransformer`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterTransformer`

  Handle inputs that start with ‘>>> ‘ syntax.

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `transform`(line, continue_prompt)

### `PythonOpsChecker`

class `IPython.core.prefilter.``PythonOpsChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)

    If the ‘rest’ of the line begins with a function call or pretty much any python operator, we should simply execute the line (regardless of whether or not there’s a possible autocall expansion). This avoids spurious (and very confusing) geattr() accesses.

  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `ShellEscapeChecker`

class `IPython.core.prefilter.``ShellEscapeChecker`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterChecker`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  `check`(line_info)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `enabled`

    A boolean (True, False) trait.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `priority`

    A integer trait.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

### `ShellEscapeHandler`

class `IPython.core.prefilter.``ShellEscapeHandler`(shell=None, prefilter_manager=None, config=None)

  Bases: `IPython.core.prefilter.PrefilterHandler`

  `__init__`(shell=None, prefilter_manager=None, config=None)
  classmethod `class_config_section`()

    Get the config class config section

  classmethod `class_get_help`()

    Get the help string for this class in ReST format.

  classmethod `class_get_trait_help`(trait)

    Get the help string for a single trait.

  classmethod `class_print_help`()

    Get the help string for a single trait and print it.

  classmethod `class_trait_names`(**metadata)

    Get a list of all the names of this classes traits.

    This method is just like the `trait_names()` method, but is unbound.

  classmethod `class_traits`(**metadata)

    Get a list of all the traits of this class.

    This method is just like the `traits()` method, but is unbound.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

  `config`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `created` = None
  `esc_strings`

    An instance of a Python list.

  `handle`(line_info)

    Execute the line in a shell, empty return value

  `handler_name`

    A trait for unicode strings.

  `on_trait_change`(handler, name=None, remove=False)

    Setup a handler to be called when a trait changes.

    This is used to setup dynamic notifications of trait changes.

    Static handlers can be created by creating methods on a HasTraits subclass with the naming convention ‘_[traitname]_changed’. Thus, to create static handler for the trait ‘a’, create the method _a_changed(self, name, old, new) (fewer arguments can be used, see below).

    Parameters :

    handler : callable

    > A callable that is called when a trait changes. Its signature can be handler(), handler(name), handler(name, new) or handler(name, old, new).

    name : list, str, None

    > If None, the handler will apply to all traits. If a list of str, handler will apply to all names in the list. If a str, the handler will apply just to that name.

    remove : bool

    > If False (the default), then install the handler. If True then unintall it.

  `prefilter_manager`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `shell`

    A trait whose value must be an instance of a specified class.

    The value can also be an instance of a subclass of the specified class.

  `trait_metadata`(traitname, key)

    Get metadata values for trait by key.

  `trait_names`(**metadata)

    Get a list of all the names of this classes traits.

  `traits`(**metadata)

    Get a list of all the traits of this class.

    The TraitTypes returned don’t know anything about the values that the various HasTrait’s instances are holding.

    This follows the same algorithm as traits does and does not allow for any simple way of specifying merely that a metadata name exists, but has any value. This is because get_metadata returns None if a metadata key doesn’t exist.

## Function

`IPython.core.prefilter.``is_shadowed`(identifier, ip)

  Is the given identifier defined in one of the namespaces which shadow the alias and magic namespaces? Note that an identifier is different than ifun, because it can not contain a ‘.’ character.

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