Expression¶

class abjad.utilities.Expression.Expression(argument_count=None, argument_values=None, callbacks=None, evaluation_template=None, force_return=None, has_parentheses=None, is_composite=None, is_initializer=None, is_postfix=None, keywords=None, lone=None, map_operand=None, markup_maker_callback=None, module_names=None, name=None, next_name=None, precedence=None, proxy_class=None, qualified_method_name=None, string_template=None, subclass_hook=None, subexpressions=None, template=None)¶

Expression.

Makes identity expression:

>>> expression = abjad.Expression()

>>> expression() is None
True

>>> expression(99)
99

>>> expression([99, 99.25])
[99, 99.25]

Makes integer initialization expression:

>>> expression = abjad.Expression(evaluation_template='int({})')

>>> expression()
0

>>> expression(99)
99

>>> expression(99.25)
99

Makes binary integer initialization expression:

>>> expression = abjad.Expression(evaluation_template='int({}, base=2)')

>>> expression('1')
1

>>> expression('11')
3

>>> expression('111')
7

Makes three-integer addition expression:

>>> expression = abjad.Expression(
...     argument_count=3,
...     evaluation_template='{} + {} + {}',
...     )

>>> expression(1, 2, 3)
6

Attributes Summary

`__add__`	Gets proxy method or adds expressions.
`__call__`	Calls expression on `arguments` with `keywords`.
`__eq__`	Is true when expression storage format equals `argument` storage format.
`__format__`	Formats expression.
`__getattr__`	Gets attribute `name`.
`__getitem__`	Gets proxy method.
`__hash__`	Hashes expression.
`__iadd__`	Gets proxy method.
`__radd__`	Gets proxy method.
`__repr__`	Gets interpreter representation.
`__setitem__`	Gets proxy method.
`__str__`	Gets string representation of expression.
`append_callback`	Appends callback to expression.
`argument_count`	Gets argument count.
`argument_values`	Gets argument values.
`callbacks`	Gets callbacks.
`color`	Colors `argument`.
`establish_equivalence`	Makes new expression with `name`.
`evaluation_template`	Gets evaluation template.
`force_return`	Is true when expression should return primary input argument.
`get_markup`	Gets markup directly.
`get_string`	Gets string.
`has_parentheses`	Is true when expression has parentheses.
`is_composite`	Is true when expression is composite.
`is_initializer`	Is true when expression is initializer.
`is_postfix`	Is true when expression is postfix.
`is_selector`	Is true when expression is selector.
`keywords`	Gets keywords.
`label`	Makes label expression.
`lone`	Is true when expression return a singular get-item.
`make_callback`	Makes callback.
`map_operand`	Gets expression to map.
`markup_maker_callback`	Gets markup-maker callback.
`module_names`	Gets module names.
`name`	Gets name.
`next_name`	Gets next name.
`pitch_class_segment`	Makes pitch-class segment expression.
`pitch_set`	Makes pitch set expression.
`precedence`	Gets precedence.
`print`	Prints `argument`.
`proxy_class`	Gets proxy class.
`qualified_method_name`	Gets qualified method name of expression.
`select`	Makes select expression.
`sequence`	Makes sequence expression.
`string_template`	Gets string template.
`subclass_hook`	Gets subclass hook.
`subexpressions`	Gets subexpressions.
`template`	Gets template.
`wrap_in_list`	Makes expression to wrap argument in list.

Special methods

__add__(i)¶

Gets proxy method or adds expressions.

Adds expressions:

>>> expression_1 = abjad.Expression(
...     argument_count=3,
...     evaluation_template='{} + {} + {}',
...     )
>>> expression_2 = abjad.Expression(
...     argument_count=2,
...     evaluation_template='{} + {}',
...     )
>>> expression = expression_1 + expression_2
>>> abjad.f(expression)
abjad.Expression(
    argument_count=2,
    evaluation_template='{}.__add__({})',
    is_composite=True,
    markup_maker_callback='_make_add_expression_markup',
    qualified_method_name='abjad.Expression.__add__',
    string_template='{} + {}',
    subexpressions=(
        abjad.Expression(
            argument_count=3,
            evaluation_template='{} + {} + {}',
            ),
        abjad.Expression(
            argument_count=2,
            evaluation_template='{} + {}',
            ),
        ),
    )

>>> expression(1, 2, 3, 4, 5)
15

__call__(*arguments, **keywords)¶

Calls expression on arguments with keywords.

Calls identity expression:

>>> expression = abjad.Expression()

>>> expression() is None
True

Returns ouput of last callback.

(AbjadValueObject).__copy__(*arguments)¶

Copies Abjad value object.

Returns new Abjad value object.

__eq__(argument)¶

Is true when expression storage format equals argument storage format.

>>> expression_1 = abjad.Expression().sequence()
>>> expression_2 = abjad.Expression().sequence()
>>> expression_1 == expression_2
True

>>> expression_1 = abjad.Expression().sequence()
>>> expression_2 = abjad.new(expression_1)
>>> expression_1 == expression_2
True

>>> expression_1 = abjad.Expression().sequence()
>>> expression_2 = abjad.Expression().sequence().reverse()
>>> expression_1 == expression_2
False

>>> expression_1 = abjad.Expression().sequence()
>>> expression_1 == 'text'
False

Returns true or false.

__format__(format_specification='')¶

Formats expression.

Formats identity expression:

>>> expression = abjad.Expression()

>>> abjad.f(expression)
abjad.Expression()

Returns string.

__getattr__(name)¶

Gets attribute name.

Returns proxy method when proxy class is set.

Returns normally when proxy class is not set.

__getitem__(argument)¶: Gets proxy method.

__hash__()¶

Hashes expression.

Returns integer.

__iadd__(i)¶: Gets proxy method.

__radd__(i)¶: Gets proxy method.

__repr__()¶

Gets interpreter representation.

Gets interpreter representation of identity expression:

>>> expression = abjad.Expression()

>>> expression
Expression()

Returns string.

__setitem__(i, argument)¶: Gets proxy method.

__str__()¶

Gets string representation of expression.

Gets string representation of identity expression:

>>> expression = abjad.Expression()

>>> str(expression)
'Expression()'

Returns string.

Methods

append_callback(callback)¶

Appends callback to expression.

>>> expression = abjad.Expression()
>>> expression.callbacks is None
True

>>> callback = abjad.Expression(evaluation_template='int({})')
>>> expression = expression.append_callback(callback)
>>> for callback in expression.callbacks:
...     callback
... 
Expression(evaluation_template='int({})')

>>> callback = abjad.Expression(evaluation_template='{}**2')
>>> expression = expression.append_callback(callback)
>>> for expression in expression.callbacks:
...     expression
... 
Expression(evaluation_template='int({})')
Expression(evaluation_template='{}**2')

Returns new expression.

color(argument, colors=None)¶

Colors argument.

Returns none.

establish_equivalence(name)¶

Makes new expression with name.

>>> expression = abjad.Expression(name='J')
>>> expression = expression.pitch_class_segment()
>>> expression = expression.rotate(n=1)
>>> expression = expression.rotate(n=2)
>>> expression = expression.establish_equivalence(name='Q')

>>> expression([-2, -1.5, 6, 7, -1.5, 7])
PitchClassSegment([7, 10.5, 7, 10, 10.5, 6])

>>> expression.get_string()
'Q = r2(r1(J))'

>>> markup = expression.get_markup()
>>> abjad.show(markup) 

Returns new expression.

get_markup(direction=None, name=None)¶

Gets markup directly.

Avoids markup expressions.

Returns markup or none.

get_string(name=None)¶

Gets string.

Gets string for sequence expression:

Without name:

>>> expression = abjad.sequence()
>>> expression = expression.reverse()
>>> expression = expression.rotate(n=2)

>>> expression([1, 2, 3, 4, 5, 6])
Sequence([2, 1, 6, 5, 4, 3])

>>> abjad.Expression.get_string(expression, name='J')
'r2(R(J))'

With name:

>>> expression = abjad.Expression(name='J')
>>> expression = expression.sequence()
>>> expression = expression.reverse()
>>> expression = expression.rotate(n=2)

>>> expression([1, 2, 3, 4, 5, 6])
Sequence([2, 1, 6, 5, 4, 3])

>>> abjad.Expression.get_string(expression)
'r2(R(J))'

Overrides name:

>>> abjad.Expression.get_string(expression, name='K')
'r2(R(K))'

Gets string for segment expression:

Without name:

>>> expression = abjad.Expression()
>>> expression = expression.pitch_class_segment()
>>> expression = expression.invert()
>>> expression = expression.rotate(n=2)

>>> expression([-2, -1.5, 6, 7, -1.5, 7])
PitchClassSegment([1.5, 5, 2, 1.5, 6, 5])

>>> abjad.Expression.get_string(expression, name='J')
'r2(I(J))'

With name:

>>> expression = abjad.Expression(name='J')
>>> expression = expression.pitch_class_segment()
>>> expression = expression.invert()
>>> expression = expression.rotate(n=2)

>>> expression([-2, -1.5, 6, 7, -1.5, 7])
PitchClassSegment([1.5, 5, 2, 1.5, 6, 5])

>>> abjad.Expression.get_string(expression)
'r2(I(J))'

Overrides name:

>>> abjad.Expression.get_string(expression, name='K')
'r2(I(K))'

Returns string or none.

label(**keywords)¶

Makes label expression.

Makes expression to label logical tie durations:

>>> staff = abjad.Staff(r"c'4. d'8 ~ d'4. e'16 [ ef'16 ]")

>>> expression = abjad.Expression()
>>> expression = expression.label()
>>> expression = expression.with_durations()

>>> expression(staff)
>>> abjad.show(staff) 

Returns expression.

pitch_class_segment(**keywords)¶

Makes pitch-class segment expression.

Makes expression to transpose pitch-class segment:

>>> items = [-2, -1.5, 6, 7, -1.5, 7]
>>> J = abjad.PitchClassSegment(items=items)
>>> J
PitchClassSegment([10, 10.5, 6, 7, 10.5, 7])

>>> abjad.show(J) 

>>> expression = abjad.Expression(name='J')
>>> expression = expression.pitch_class_segment()
>>> expression = expression.transpose(n=13)

>>> expression([-2, -1.5, 6, 7, -1.5, 7])
PitchClassSegment([11, 11.5, 7, 8, 11.5, 8])

>>> segment = expression([-2, -1.5, 6, 7, -1.5, 7])
>>> markup = expression.get_markup()
>>> abjad.show(segment, figure_name=markup) 

Returns expression.

pitch_set(**keywords)¶

Makes pitch set expression.

Returns expression.

print(argument)¶

Prints argument.

Returns none.

select(**keywords)¶

Makes select expression.

Makes expression to select leaves:

>>> staff = abjad.Staff()
>>> staff.append(abjad.Measure((2, 8), "<c' bf'>8 <g' a'>8"))
>>> staff.append(abjad.Measure((2, 8), "af'8 r8"))
>>> staff.append(abjad.Measure((2, 8), "r8 gf'8"))
>>> abjad.show(staff) 

>>> expression = abjad.Expression()
>>> expression = expression.select()
>>> expression = expression.leaves()

>>> for leaf in expression(staff):
...     leaf
... 
Chord("<c' bf'>8")
Chord("<g' a'>8")
Note("af'8")
Rest('r8')
Rest('r8')
Note("gf'8")

Returns expression.

sequence(**keywords)¶

Makes sequence expression.

Makes expression to initialize, flatten and reverse sequence:

>>> expression = abjad.sequence()
>>> expression = expression.reverse()
>>> expression = expression.flatten(depth=-1)

>>> expression([1, 2, 3, [4, 5, [6]]])
Sequence([4, 5, 6, 3, 2, 1])

Returns expression.

wrap_in_list()¶

Makes expression to wrap argument in list.

>>> expression = abjad.Expression()
>>> expression = expression.wrap_in_list()

>>> expression(abjad.Markup('Allegro assai'))
[Markup(contents=['Allegro assai'])]

>>> abjad.f(expression)
abjad.Expression(
    callbacks=[
        abjad.Expression(
            evaluation_template='[{}]',
            ),
        ],
    )

Returns expression.

Class & static methods

static make_callback(argument_count=None, evaluation_template=None, force_return=None, has_parentheses=None, is_composite=None, is_initializer=None, is_postfix=None, keywords=None, map_operand=None, module_names=None, next_name=None, precedence=None, qualified_method_name=None, string_template=None)¶

Makes callback.

Returns expression.

Read-only properties

argument_count¶

Gets argument count.

Defaults to none.

Set to nonnegative integer or none.

Returns nonnegative integer or none.

argument_values¶

Gets argument values.

Defaults to none.

Set to dictionary or none.

Returns dictionary or none.

callbacks¶

Gets callbacks.

Defaults to none:

>>> expression = abjad.Expression()
>>> expression.callbacks is None
True

Set to callbacks or none.

evaluation_template¶

Gets evaluation template.

Defaults to none.

Set to string.

Returns string.

force_return¶

Is true when expression should return primary input argument.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

has_parentheses¶

Is true when expression has parentheses.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

is_composite¶

Is true when expression is composite.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

is_initializer¶

Is true when expression is initializer.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

is_postfix¶

Is true when expression is postfix.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

is_selector¶

Is true when expression is selector.

>>> expression = abjad.select().leaf(0)
>>> expression.is_selector
True

>>> expression = abjad.sequence().rotate(n=-1)
>>> expression.is_selector
False

keywords¶

Gets keywords.

Defaults to none.

Set to dictionary or none.

Returns dictionary or none.

lone¶

Is true when expression return a singular get-item.

Defaults to none.

Set to true, false or none.

Returns true, false or none.

map_operand¶

Gets expression to map.

Defaults to none.

Set to expression or none.

Returns expression or none.

markup_maker_callback¶

Gets markup-maker callback.

Defaults to none.

Set to string or none.

Returns string or none.

module_names¶

Gets module names.

Defaults to none.

Set to strings or none.

Returns strings or none.

name¶

Gets name.

Preserves name after initializer callback:

>>> expression = abjad.Expression(name='J')
>>> expression.name
'J'

>>> expression = expression.sequence()
>>> expression.name
'J'

Defaults to none.

Set to string or none.

Returns string or none.

next_name¶

Gets next name.

Defaults to none.

Set to string or none.

Returns string or none.

precedence¶

Gets precedence.

Defaults to none.

Set to integer or none.

Returns integer or none.

proxy_class¶

Gets proxy class.

Defaults to none.

Set to class or none.

Returns class or none.

qualified_method_name¶

Gets qualified method name of expression.

Returns string or none.

string_template¶

Gets string template.

Defaults to none.

Set to string or none.

Returns string or none.

subclass_hook¶

Gets subclass hook.

Only to be set by expression subclasses.

Set to name of custom evaluation method.

Defaults to none.

Set to string or none.

Returns string or none.

subexpressions¶

Gets subexpressions.

Defaults to none.

Set to expressions or none.

Returns list of expressions or none.

template¶

Gets template.

Returns string or none.