Component Index¶

Any Component class can be added to the cqparts search index, allowing it to be found by other modules with concise code

This includes anything we’ve made in Make your own Part and Make your own Assembly.

Registering, and searching is all done by the cqparts.search module.

Registering¶

Adding a Component to the search index is done in one of 2 ways.

Decorator¶

You can use the register() method as a class decorator.

>>> import cqparts
>>> from cqparts.search import register
>>> from cqparts.params import *

>>> @register(a='one', b='two')
... class SomeThing(cqparts.Part):
...     length = Float(10)

>>> @register(a='one', b='three')
... class AnotherThing(cqparts.Assembly):
...     height = Int(100)

This has added thse two components to the cqparts search index.

Note that:

SomeThing is a Part, and AnotherThing is an Assembly. It actually doesn’t matter what they are, they will be added to the index, but they should be a Component of some sort.
Both SomeThing and AnotherThing have a common criteria a='one'

Tip

Make your component’s criteria unique.

If it is not unique you run the risk of making yours, or other’s components fail in searches.

Possibly employ common_criteria() to clean up your code.

Direct Register¶

Components can also be registered by the register() method without using it as a decorator.

>>> import cqparts
>>> from cqparts.search import register
>>> from cqparts.params import *

>>> class _SomeThing(cqparts.Part):
...     length = Float(10)
>>> SomeThing = register(a='one', b='two')(_SomeThing)

>>> class _AnotherThing(cqparts.Assembly):
...     height = Int(100)
>>> AnotherThing = register(a='one', b='three')(_AnotherThing)

This and the decorated approach are functionally identical, which method you use is dependent on your library’s design, and which best suits you.

Searching & Finding¶

The 2 parts registered above can be found again with search() and/or find():

Search¶

search() returns a set of all components that match the given search criteria:

>>> from cqparts.search import search

>>> search(a='one')
{__main__.SomeThing, __main__.AnotherThing}

>>> search(b='two', a='one')
{__main__.SomeThing}

Find¶

But most of the time you’ll only be expecting one part to bounce back, because mostly this is intended as an indexing tool, not a searching tool.

To index a unique part, or fail (throw a SearchError exception), use find() instead:

>>> from cqparts.search import find

>>> find(a='one', b='two')
__main__.SomeThing

>>> # You can use this to build a component straight away
>>> find(a='one', b='two')(length=50)  # creates an instance
<SomeThing: length=50.0>

This is great for finding a component class with a registered part number.

Using find() with criteria that is not unique will raise a SearchMultipleFoundError exception:

>>> find(a='one')
SearchMultipleFoundError: 2 results found

Similarly, calling find() with criteria that is not indexed will raise a SearchNoneFoundError exception:

>>> find(b='infinity')
SearchNoneFoundError: 0 results found