Custom converter support in select()

[lambda-xyz]

It's easy to add a new type to entity attributes with custom Converter but I would like to be able to filter query in select using this new type.

Here is a small example:

from enum import Enum
from pony import orm
from pony.orm import Database, Required, db_session, select
from pony.orm.dbapiprovider import StrConverter

class EnumConverter(StrConverter):
    def validate(self, val, obj=None):
        if not isinstance(val, Enum):
            raise ValueError('Must be an Enum. Got {}'.format(val))
        return val

    def py2sql(self, val):
        return val.name

    def sql2py(self, val):
        return self.py_type[val]

    def sql_type(self):
        return 'VARCHAR(30)'

db = Database('sqlite', ':memory:', create_db=True)
db.provider.converter_classes.append((Enum, EnumConverter))


class ProcState(Enum):
    idle = 0
    running = 1
    error = 2


class Process(db.Entity):
    name = Required(str)
    state = Required(ProcState)
    pid = Required(int)


db.generate_mapping(create_tables=True)

with db_session:
    Process(name='chromium', state=ProcState.idle, pid=12)
    Process(name='firefox', state=ProcState.error, pid=15)
    Process(name='surf', state=ProcState.running, pid=19)
    Process(name='epiphany', state=ProcState.running, pid=22)

Actually the only way I found is to use raw_sql like in req3:

with db_session:
    # doesn't work: TypeError
    # req1 = select(p for p in Process if p.state == ProcState.running)
    # doesn't work: TypeError
    # req2 = select(p for p in Process if getattr(p, 'state') == ProcState.running)
    # works!
    req3 = select(p for p in Process if orm.raw_sql('p.state == "running"'))

    req3[:].show(500)

Is there any possibility to use select using req1 syntax?

[GammaGames]

I would at least like Enum support (hopefully this can get completed and merged) because the reason I found this issue was to try and select based on an enum.

[pykler]

Adding an

class ProcState(Enum):
...
    def __str__(self):
        return self.name

Allows you to use the enum in queries. It is a hack but it works