knit_script.knit_script_interpreter.statements.Drop_Pass module

A pass of drop operations.

This module provides the Drop_Pass statement class, which implements specialized carriage passes that drop stitches from specified needles.

It creates dedicated drop operations that are executed in a consistent direction for reliable stitch removal.

class Drop_Pass(parser_node, needles)

Bases: Statement

Executes a set of drop operations from left to right.

Creates a specialized carriage pass that drops stitches from the specified needles. Always executes in rightward direction for consistency and proper machine operation. This statement is used when stitches need to be removed from needles, typically for shaping operations or pattern requirements.

The drop pass handles evaluation of needle expressions, flattening of nested needle lists, and creation of appropriate carriage pass specifications for reliable stitch dropping operations.

_needles

List of expressions that evaluate to needles to drop from.

Type:

list[Expression]

__init__(parser_node, needles)

Initialize a drop pass.

Parameters:

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

• needles (list[Expression]) – List of expressions that evaluate to needles to drop from. Can include nested lists of needles which will be flattened during execution.

execute(context)

Execute drop operations on all specified needles.

Evaluates all needle expressions, flattens any nested lists, validates that all results are Needle objects, then creates a carriage pass to drop all stitches.

The results are stored in the context for potential use by subsequent operations.

Parameters:

context (Knit_Script_Context) – The current execution context of the knit script interpreter.

Raises:

TypeError – If any expression doesn’t evaluate to a Needle object.

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 execute methods in subclasses with appropriate error handling and debugging decorators.

This method is called whenever a class inherits from Statement. It checks if the subclass defines its own execute method and wraps it with the appropriate decorators

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