knit_script.knit_script_interpreter.expressions.not_expression module

Expressions for interpreting conditions using Python conventions.

This module provides the Not_Expression class, which implements logical negation operations in knit script programs. It follows Python’s truthiness conventions for evaluating and negating expressions.

class Not_Expression(parser_node, negated_expression)

Bases: Expression

Expression with a “not” operator negating them.

The Not_Expression class implements logical negation operations following Python’s conventions for truthiness evaluation. It takes any expression and returns the logical negation of its evaluated result, converting the result to a boolean using Python’s standard truthiness rules.

This expression type is essential for conditional logic in knit script programs,

allowing developers to negate boolean conditions, check for empty collections, None values, and other false conditions.

_negated_expression

The expression to logically negate.

Type:

Expression

__init__(parser_node, negated_expression)

Initialize the Not_Expression.

Parameters:

• parser_node (LRStackNode) – The parser node from the parse tree.

• negated_expression (Expression) – The expression to apply logical negation to.

evaluate(context)

Evaluate the expression to get the logical negation result.

Evaluates the contained expression and returns its logical negation, following Python’s truthiness conventions where empty collections, None, zero values, and False are considered false.

Parameters:

context (Knit_Script_Context) – The current context of the knit_script_interpreter.

Returns:

The logical negation of the evaluated expression result.

Return type:

bool

classmethod __class_getitem__(params)

Parameterizes a generic class.

At least, parameterizing a generic class is the main thing this method does. For example, for some generic class Foo, this is called when we do Foo[int] - there, with cls=Foo and params=int.

However, note that this method is also called when defining generic classes in the first place with class Foo(Generic[T]): ….

classmethod __init_subclass__(**kwargs)

Automatically wrap evaluate methods in subclasses with appropriate error handling decorator.

This method is called whenever a class inherits from Expression. It checks if the subclass defines its own evaluate method and wraps it with the appropriate decorator.

Parameters:

**kwargs (Any) – Additional keyword arguments passed to super().__init_subclass__

property file_name: str | None

Returns: str | None: The file name of the knitscript program this was parsed from or None if the program was passed as a string.

property line_number: int

Get the line number of the symbol that generated this statement.

Returns:

The line number where this element appears in the source file.

Return type:

int

property local_path: str | None

Returns: str | None: The path to the directory containing the file from which this element was parsed or None if the value was parsed from a python string.

property location: Location

Get the location of this symbol in KnitScript file.

Returns:

The location of this symbol in the source file, including file name, line number, and position information.

Return type:

Location

property location_str: str

Returns: str: The string referencing the line number and possible file name information about this element.

property position_context: str

The position context string is the string from the knitscript program from which this element was parsed. The context string will begin at the start of this element and continue to the end of the line of knitscript or a semicolon on new line are reached.

Returns:

The string used to contextualize this element in the knitscript program.

Return type:

str