SigScaffold

A lightweight Python tool to derive structured information from the signatures of functions and classes.

SigScaffold inspects any callable (like a function or a class constructor) and extracts details about its parameters, including their names, types, and default values. This is particularly useful for automatically generating documentation, configuration files, or API contracts.

Features

• Get parameter names and their type annotations.
• Recursively inspect signatures of class-based parameters.
• Identify which parameters are required.
• Generate sensible default values for all parameters.
• No external dependencies.

Installation

pip install sig-scaffold

Usage

Here is a quick example of how to use SigScaffold:

from sig_scaffold import SigScaffold

# -- Define a class to inspect ---
class DatabaseConfig:
    def __init__(self, host: str, port: int = 5432):
        self.host = host
        self.port = port

def connect(db_config: DatabaseConfig, timeout: int = 30):
    """Connects to a database with the given configuration."""
    pass

# -- Use SigScaffold ---

# 1. Inspect the 'connect' function
scaffold = SigScaffold(connect)

# 2. Get parameter types (with recursion)
# This will look inside the DatabaseConfig class as well.
param_types = scaffold.get_param_types(recursive=True)
print("Parameter Types:")
# Expected output:
# {
#   'db_config': {'host': <class 'str'>, 'port': <class 'int'>},
#   'timeout': <class 'int'>
# }
import json
print(json.dumps(
    {k: str(v) for k, v in param_types.items()},
    indent=2
))


# 3. Get only the required parameters
required = scaffold.get_required_params()
print(f"\nRequired Parameters: {required}")
# Expected output: ['db_config']

# 4. Generate default values for all parameters
defaults = scaffold.generate_defaults()
print(f"\nGenerated Defaults: {defaults}")
# Expected output: {'db_config': '', 'timeout': 30}