Module 03: Signatures, Provenance, and Runtime Evidence¶

Page Maps¶

graph LR
  family["Python Programming"]
  program["Python Meta-Programming"]
  section["Signatures Provenance Runtime Evidence"]
  page["Module 03: Signatures, Provenance, and Runtime Evidence"]
  capstone["Capstone evidence"]

  family --> program --> section --> page
  page -.applies in.-> capstone

flowchart LR
  orient["Orient on the page map"] --> read["Read the main claim and examples"]
  read --> inspect["Inspect the related code, proof, or capstone surface"]
  inspect --> verify["Run or review the verification path"]
  verify --> apply["Apply the idea back to the module and capstone"]

Module 03 turns raw inspection into stronger evidence. It introduces inspect as the structured introspection layer that documentation tools, debuggers, wrappers, and runtime frameworks rely on when "it looks inspectable" is no longer a strong enough claim.

This module now uses the same ten-file learning surface as the deep-dive series so the overview, five cores, worked example, practice set, answers, and glossary each have one clear job.

What this module is for¶

By the end of Module 03, you should be able to explain five things clearly:

what inspect.signature proves about a callable contract
how bind() turns a signature into interpreter-like argument matching
why provenance helpers are useful but remain best-effort evidence
how dynamic member enumeration differs from static structural inspection
why frame and stack introspection belong to diagnostics rather than ordinary control flow

Keep these pages open¶

The ten files in this module¶

How to use the file set¶

If you need to...	Start here
understand what a callable contract really contains	Signature Contracts and Parameter Kinds
validate or forward arguments without reimplementing Python's call rules	Argument Binding and Call Simulation
recover source or file context without pretending provenance is perfect	Provenance Helpers and Best-Effort Recovery
separate dynamic value enumeration from safe structural inspection	Dynamic Members and Static Structure
keep stack and frame introspection in the diagnostics bucket	Frames and Diagnostic-Only Runtime Evidence
see safe evidence-collection choices inside one realistic helper	Worked Example: Building a Safe Signature-Guided `__repr__`
test your understanding before wrappers and decorators begin	Exercises
compare your reasoning against a reference answer	Exercise Answers
stabilize the module vocabulary	Glossary

The running question¶

Carry this question through every page:

What runtime evidence is strong enough to trust, and what evidence stays best-effort or diagnostic-only?

Strong Module 03 answers usually mention one or more of these:

a Signature object describing callable structure
bind() as interpreter-like argument matching
best-effort provenance from source and file helpers
static versus dynamic member inspection
frames and stacks as diagnostic surfaces with cost and retention hazards

Learning outcomes¶

By the end of this module, you should be able to:

use inspect to gather runtime facts without overstating what those facts prove
preserve or validate callable metadata in wrapper-heavy designs
separate correctness-grade evidence from best-effort provenance and diagnostic tooling
explain why the capstone exposes callable facts without turning inspection into uncontrolled execution

Exit standard¶

Do not move on until all of these are true:

you can explain what inspect.signature proves and what it does not
you can use bind() or bind_partial() instead of reimplementing call matching
you can say why getsource, getfile, and getmodule are useful but not correctness foundations
you can distinguish structural inspection from dynamic member resolution and diagnostic stack inspection

When those feel ordinary, Module 03 has done its job and the decorator modules can build on a stronger evidence discipline.