type_bridge.expressions.string

string

String-specific expressions for text filtering.

See :mod:type_bridge.expressions.utils for documentation on TypeDB 3.x variable scoping and why we generate unique attribute variables.

StringExpr

StringExpr(attr_type, operation, pattern)

Bases: Expression

Type-safe string expression for text-based filtering.

Represents string operations like contains, like (regex), etc.

Create a string expression.

Parameters:

Name	Type	Description	Default
attr_type	type[T]	String attribute type to filter on	required
operation	Literal['contains', 'like', 'regex']	String operation type	required
pattern	T	Pattern to match	required

Source code in type_bridge/expressions/string.py

def __init__(
    self,
    attr_type: type[T],
    operation: Literal["contains", "like", "regex"],
    pattern: T,
):
    """Create a string expression.

    Args:
        attr_type: String attribute type to filter on
        operation: String operation type
        pattern: Pattern to match
    """
    self.attr_type = attr_type
    self.operation = operation
    self.pattern = pattern

to_ast

to_ast(var)

Generate AST patterns for this string operation.

Example: "$e has Name $e_name; $e_name contains 'Alice'"

Parameters:

Name	Type	Description	Default
var	str	Entity variable name (e.g., "$e", "$actor")	required

Returns:

Type	Description
list[Pattern]	List of AST patterns

Source code in type_bridge/expressions/string.py

def to_ast(self, var: str) -> list["Pattern"]:
    """Generate AST patterns for this string operation.

    Example: "$e has Name $e_name; $e_name contains 'Alice'"

    Args:
        var: Entity variable name (e.g., "$e", "$actor")

    Returns:
        List of AST patterns
    """
    from type_bridge.query.ast import (
        HasPattern,
        LiteralValue,
        ValueComparisonPattern,
    )

    attr_type_name = self.attr_type.get_attribute_name()
    attr_var = generate_attr_var(var, self.attr_type)

    # Map operation to TypeQL keyword
    # AUTOMATIC CONVERSION: regex() → 'like' in TypeQL
    typeql_op = "like" if self.operation == "regex" else self.operation

    return [
        HasPattern(thing_var=var, attr_type=attr_type_name, attr_var=attr_var),
        ValueComparisonPattern(
            var=attr_var,
            operator=typeql_op,
            value=LiteralValue(value=self.pattern.value, value_type="string"),
        ),
    ]