Managing Multiple Templates

Representing different path structures requires the use of multiple templates.

Lucidity provides a few helper functions for dealing with multiple templates.

Template Discovery

Templates can be discovered by searching a list of paths for mount points that register template instances. By default, the list of paths is retrieved from the environment variable LUCIDITY_TEMPLATE_PATH.

To search and load templates in this way:

>>> import lucidity
>>> templates = lucidity.discover_templates()

To specify a specific list of paths just pass them to the function:

>>> templates = lucidity.discover_templates(paths=['/templates'])

By default each path will be recursively searched. You can disable this behaviour by setting the recursive keyword argument:

>>> templates = lucidity.discover_templates(recursive=False)

Template Mount Points

To write a template mount point, define a Python file containing a register function. The function should return a list of instantiated Template instances:


from lucidity import Template

def register():
    '''Register templates.'''
    return [
        Template('job', '/jobs/{job.code}'),
        Template('shot', '/jobs/{job.code}/shots/{scene.code}_{shot.code}')

Place the file on one of the search paths for discover_templates() to have it take effect.

Operations Against Multiple Templates

Lucidity also provides two top level functions to run a parse or format operation against multiple candidate templates using the first correct result found.

Given the following templates:

>>> import lucidity
>>> templates = [
...     lucidity.Template('model', '/jobs/{job}/assets/model/{lod}'),
...     lucidity.Template('rig', '/jobs/{job}/assets/rig/{rig_type}')
... ]

To perform a parse:

>>> print lucidity.parse('/jobs/monty/assets/rig/anim', templates)
({'job': 'monty', 'rig_type': 'anim'},
 Template(name='rig', pattern='/jobs/{job}/assets/rig/{rig_type}'))

To format data:

>>> print lucidity.format({'job': 'monty', 'rig_type': 'anim'}, templates)
 Template(name='rig', pattern='/jobs/{job}/assets/rig/{rig_type}'))


The return value is a tuple of (result, template).

If no template could provide a result an appropriate error is raised ( ParseError or FormatError).