Compound Fields

class DateYYYYMMDD(value=Unspecified, **kw)

Bases: flatland.schema.compound.Compound, flatland.schema.scalars.Date

compose()

Return a text, native tuple built from children’s state.

Returns:a 2-tuple of text representation, native value. These correspond to the serialize_element() and adapt_element() methods of Scalar objects.

For example, a compound date field may return a ‘-‘ delimited string of year, month and day digits and a datetime.date.

explode(value)

Given a compound value, assign values to children.

Parameters:value – a value to be adapted and exploded

For example, a compound date field may read attributes from a datetime.date value and set() them on child fields.

The decision to perform type checking on value is completely up to you and you may find you want different rules for different compound types.

class JoinedString(value=Unspecified, **kw)

Bases: flatland.schema.containers.Array, flatland.schema.scalars.String

A sequence container that acts like a compounded string such as CSV.

Marshals child element values to and from a single string:

>>> from flatland import JoinedString
>>> el = JoinedString(['x', 'y', 'z'])
>>> el.value
u'x,y,z'
>>> el2 = JoinedString('foo,bar')
>>> el2[1].value
u'bar'
>>> el2.value
u'foo,bar'

Only the joined representation is considered when flattening or restoring with set_flat(). JoinedStrings run validation after their children.

separator = u','

The string used to join children’s u representations. Will also be used to split incoming strings, unless separator_regex is also defined.

separator_regex = None

Optional, a regular expression, used preferentially to split an incoming separated value into components. Used in combination with separator, a permissive parsing policy can be combined with a normalized representation, e.g.:

>>> import re
>>> schema = JoinedString.using(separator=', ',
...                             separator_regex=re.compile('\s*,\s*'))
...
>>> schema('a  ,  b,c,d').value
u'a, b, c, d'

member_schema

alias of flatland.schema.scalars.String

set(value)

Assign the native and Unicode value.

Attempts to adapt the given iterable and assigns this element’s value and u attributes in tandem. Returns True if the adaptation was successful. See Element.set().

Set must be supplied a Python sequence or iterable:

>>> from flatland import Integer, List
>>> Numbers = List.of(Integer)
>>> nums = Numbers()
>>> nums.set([1, 2, 3, 4])
True
>>> nums.value
[1, 2, 3, 4]

value

A read-only separator-joined string of child values.

u

A read-only separator-joined string of child values.