Using Cached Symbols

EQL provides a cache for all symbol classes. Whenever python creates an object of a class that inherits from Symbol, EQL will cache the instance in the symbol graph. When you create a free variable via let without a domain, EQL will use the Symbol Graph to extract the domain.

Warning

When you have a lot of instances of a type but your query requires only a few of them, EQL will check a lot of unnecessary instances. Provide a domain in such cases.

from dataclasses import dataclass

from typing_extensions import List

from krrood.entity_query_language.entity import entity, an, let, contains, Symbol


@dataclass
class Body(Symbol):
    name: str


@dataclass
class World:
    id_: int
    bodies: List[Body]


world = World(1, [Body("Body1"), Body("Body2")])

body = let(Body, domain=None)  # no domain here
query = an(
    entity(
        body,
        contains(body.name, "2"),
        body.name.startswith("Body"),
    )
)

print(*query.evaluate(), sep="\n")

Body(name='Body2')