AST Utils

Bases: RuntimeError

Internal error encountered while processing AST.

Bases: Exception

Base exception for callable contract violations.

Bases: ContractError

Raised when a callable attempts to access instances not passed as parameters or when decorated functions attempt to access class attributes instead of parameter instance attributes.

Bases: ContractError

Raised when a callable parameter, or accessed attribute is not a subclass of Fact.

Bases: ContractError

Raised when a decorated function has any missing type hints, an incorrect return type, or if a lambda that requires arguments is provided.

Bases: NodeTransformer

Transformer to replace static class attribute access with parameterized instances.

Index entry for tracking the parsing position of lambda functions in source lines.

Attributes:

• source (str) –

  The source code string containing lambda functions

• positions (list[int]) –

  Positions where lambda functions are found in the source

• index (int) –

  The lambda being parsed within the source string.

• in_use (bool) –

  Whether this source is currently being processed or not, making it eligible for cache deletion.

This class extracts source code from functions or lambda expressions, parses them into Abstract Syntax Trees (AST), and performs various validations and transformations.

The processor validates that: - Functions have proper type hints for parameters and return types - All parameters are subclasses of Fact - No nested attribute access (e.g., X.y.z) is used - No async functions are processed - Lambda expressions do not contain parameters - No duplicate parameter types in function signatures

For lambda expressions, it automatically transforms attribute access patterns (e.g., ClassName.attribute) into parameterized functions for easier execution.

Note: This class is not thread-safe and should not be used concurrently across multiple threads.

Attributes:

• func (T) –

  The callable to process, a lambda or a function

• decorator (Callable) –

  The decorator type that initiated the processing (e.g., condition or action)

• return_type (type | TypeAliasType) –

  Expected return type for the callable

• source (str) –

  Extracted source code of func (set during post-init)

• tree (Module) –

  Parsed AST of the source code (set during post-init)

• facts (tuple[str, ...]) –

  Tuple of fact strings discovered in the callable (set during post-init)

Raises:

• OSError –

  When source code cannot be extracted

• ScopeAccessError –

  When accessing undefined classes or using nested attributes

• CallableSignatureError –

  When function signature doesn't meet requirements

• NotAFactError –

  When parameter types are not Fact subclasses

• ASTProcessingError –

  When AST processing encounters internal errors