Modeller

Current lib provides simple and common interface for making abstract specifications, and then compile to any defined or custom dialect.

Using dialects

Using dialects to compile abstract specification to backend related code.

from modeller import SModel
from modeller.dialects.defined import SqlAlchemyDialect, MongoDbDialect, PythonDialect

# Test model
class TestModel(SModel):
    a: str = 'asfasfas'
    b: int

# Test specification
spec = (TestModel.b > 12) & (TestModel.a == '1')


# Instancing dialects
sqlalchemy_dialect = SqlAlchemyDialect()

# Sqlalchemy spec compiling
sqlalchemy_spec = sqlalchemy_dialect.make(spec)

# Compiling spec forsure
from sqlalchemy.dialects.postgresql import dialect
g = sqlalchemy_spec.compile(dialect=dialect(), compile_kwargs={"render_postcompile": True, 'literal_binds': True})  # b > 12 AND a = '1'


# Mongodb spec compiling
mongodb_dialect = MongoDbDialect()
mongodb_spec = mongodb_dialect.make(spec)  # {'$and': [{'b': {'$gt': 12}}, {'a': '1'}]}


# Python callable spec compiling
python_dialect = PythonDialect()
python_spec = python_dialect.make(spec)

# Testing python spec by filtering model instances
sp = [TestModel(a='1', b=13), TestModel(a='2', b=100), TestModel(a='3', b=1)]
result = list(filter(lambda model: python_spec(model), sp))  # [TestModel{'a': '1', 'b': 13}]

Implement custom dialect

Writting custom dialect based on default Dialect class.

from modeller import Dialect

class CustomDialect(Dialect):
    
    # Define handling for each of operation methods
    def _and_(self, value1: Any, value2: Any):
        return {'and': [value1, value2]}

    def _or_(self, value1: Any, value2: Any):
        return {'or': [value1, value2]}

    def _not_(self, value: Any):
        return {'not': value}

    def _equal_(self, value1: Any, value2: Any):
        return {'eq': [value1, value2]}

    def _not_equal_(self, value1: Any, value2: Any):
        return {'neq': [value1, value2]}

    def _lt_(self, value1: Any, value2: Any):
        return {'lt': [value1, value2]}

    def _gt_(self, value1: Any, value2: Any):
        return {'gt': [value1, value2]}

    def _lte_(self, value1: Any, value2: Any):
        return {'lte': [value1, value2]}

    def _gte_(self, value1: Any, value2: Any):
        return {'gte': [value1, value2]}

    def _in_(self, value1: Any, value2: Any):
        return {'in': [value1, value2]}

    def _has_(self, value1: Any, value2: Any):
        return {'has': [value1, value2]}

    def _has_any_(self, value1: Any, value2: Any):
        raise NotImplemented