Custom Predicates

Define custom operators with ORM-specific lowering.

Define the operator

from pyrsql import CustomPredicateDefinition, QueryOptions
from pyrsql.parsing.operators import ComparisonOperator

all_match = ComparisonOperator(
    name="all_match",
    spellings=("=all=",),
    minimum_arguments=1,
    maximum_arguments=1,
)

Register with QueryOptions

options = QueryOptions(
    custom_predicates={
        "all_match": CustomPredicateDefinition(
            operator=all_match,
            argument_type=str,
        ),
    },
)
query = Query.parse("name=all=demo", options=options)

ORM-specific lowering (SQLAlchemy)

from pyrsql.orms.sqlalchemy import SQLAlchemyORM
from sqlalchemy import func

orm = SQLAlchemyORM(
    custom_predicates={
        "all_match": lambda payload: (
            func.lower(payload.expression) == str(payload.values[0]).lower()
        ),
    },
)

The payload object provides:

• payload.expression - the resolved SQLAlchemy column
• payload.values - converted argument values
• payload.field_path - the resolved field path
• payload.options - the QueryOptions in use