grid refactoring - Githubissues

added support for Expressions in columns
added support for virtual fields in joins
_make_field was unused so was eliminated
eliminated self.formatters (was unused and better handled in Column definition
changed meaning of self.formatters_by_type. the type key is no longer the Field type but the actual python type of the value to be displayed. In this way it does not conflict with field represent.
made more consistent use of - and . in class names.
added a class grid-cell-{name}

This now works for example:

db.define_table(
    'thing',
    Field('name', requires=IS_NOT_EMPTY()),
    Field.Virtual('name2', lambda row: row["name"]),
    Field('in_stock', 'boolean', default=True),
    Field('f_date', 'date', default=datetime.date.today()),
    Field('f_datetime', 'datetime', default=datetime.datetime.now()),
    Field('f_time', 'time', default="12:30"),
    Field('properties', 'list:string'),
    Field('image', 'upload', download_url=lambda name: URL('download', name)),
)

db.define_table(
    'part',
    Field('thing_id', "reference thing"),
    Field('name', requires=IS_NOT_EMPTY()),
    Field('weight', "float"),
)

@action('index')
@action('index/{path:path}')
@action.uses('generic.html', db)
def _(path=None):
    query = db.thing.id > 0
    weight = db.part.weight.sum()
    left = db.part.on(db.thing.id==db.part.thing_id)
    grid = Grid(path, query=query, left=left, groupby=db.thing.id, 
                columns=[
                    db.thing.name,
                    db.thing.name2,
                    db.thing.in_stock,  # shows as checkbox, was broken, use unicode now
                    db.thing.f_date,
                    db.thing.f_datetime,
                    db.thing.f_time,
                    db.thing.properties,
                    weight, # did not work before
                    Column("weight", lambda row: row[weight], required_fields=[weight]) # same as above
                ])
    return locals()

web2py / py4web

grid refactoring #893