# The Art of Eyepl — inline examples These files are generated from the complete `eyepl` code blocks in [The Art of Eyepl](../../the-art-of-eyepl.md). They are grouped by chapter and retain the source text from the book. Goal fragments and non-Eyepl blocks are not extracted. Regenerate them from the repository root with: ```sh npm run generate ``` ## Chapter 1: A program is a little theory - [01-parent.pl](chapter-01/01-parent.pl) - [02-child.pl](chapter-01/02-child.pl) ## Chapter 2: Terms, variables, and substitution - [01-measurement.pl](chapter-02/01-measurement.pl) - [02-label.pl](chapter-02/02-label.pl) ## Chapter 3: Rules and their two readings - [01-eligible.pl](chapter-03/01-eligible.pl) - [02-adult.pl](chapter-03/02-adult.pl) - [03-can_enter.pl](chapter-03/03-can_enter.pl) - [04-high_score.pl](chapter-03/04-high_score.pl) - [05-parent.pl](chapter-03/05-parent.pl) — The Herbrand world - [06-ancestor.pl](chapter-03/06-ancestor.pl) - [07-different.pl](chapter-03/07-different.pl) — Why terms denote themselves - [08-has_parent.pl](chapter-03/08-has_parent.pl) — Quantification and visible witnesses - [09-program.pl](chapter-03/09-program.pl) — Equality, unification, and the occurs check - [10-closed.pl](chapter-03/10-closed.pl) — Meaning is not the search strategy - [11-p.pl](chapter-03/11-p.pl) ## Chapter 4: Recursion: describing reachability - [01-path.pl](chapter-04/01-path.pl) — Constructing the recursive argument ## Chapter 5: Lists as relations - [01-first.pl](chapter-05/01-first.pl) - [02-reverse_acc.pl](chapter-05/02-reverse_acc.pl) ## Chapter 6: Arithmetic and finite generation - [01-next.pl](chapter-06/01-next.pl) - [02-safe_reading.pl](chapter-06/02-safe_reading.pl) - [03-square.pl](chapter-06/03-square.pl) - [04-factorial.pl](chapter-06/04-factorial.pl) ## Chapter 7: Failure, negation, and quantification - [01-allowed.pl](chapter-07/01-allowed.pl) - [02-all_tests_pass.pl](chapter-07/02-all_tests_pass.pl) ## Chapter 8: Collecting and choosing answers - [01-findall.pl](chapter-08/01-findall.pl) - [02-outgoing_costs.pl](chapter-08/02-outgoing_costs.pl) - [03-best_route.pl](chapter-08/03-best_route.pl) ## Chapter 9: Structured data, strings, and contexts - [01-functor.pl](chapter-09/01-functor.pl) - [02-normalized.pl](chapter-09/02-normalized.pl) - [03-message.pl](chapter-09/03-message.pl) ## Chapter 10: From puzzles to models - [01-plan.pl](chapter-10/01-plan.pl) ## Chapter 11: Queries, answers, and proofs - [01-why.pl](chapter-11/01-why.pl) ## Chapter 12: Integrity checks as ordinary predicates - [01-invalid_probability.pl](chapter-12/01-invalid_probability.pl) - [02-invalid_assignment.pl](chapter-12/02-invalid_assignment.pl) ## Chapter 14: Knowledge engineering - [01-heating.pl](chapter-14/01-heating.pl) ## Chapter 15: RDF 1.2 as the interoperable data boundary - [01-rdf.pl](chapter-15/01-rdf.pl) ## Chapter 16: Embedding Eyepl - [01-socket.pl](chapter-16/01-socket.pl) — Sockets: naming the knowledge boundary - [02-socket-2.pl](chapter-16/02-socket-2.pl) ## Chapter 17: Logic and control - [01-path.pl](chapter-17/01-path.pl) - [02-adult.pl](chapter-17/02-adult.pl) — The same relation, a different computation - [03-bad_member.pl](chapter-17/03-bad_member.pl) - [04-item.pl](chapter-17/04-item.pl) ## Chapter 18: Constructing a program - [01-routeable.pl](chapter-18/01-routeable.pl) — Begin with ground sentences - [02-routeable-2.pl](chapter-18/02-routeable-2.pl) - [03-prefix.pl](chapter-18/03-prefix.pl) — Invent examples before recursion - [04-candidate_pair.pl](chapter-18/04-candidate_pair.pl) — Separate generate, test, and describe - [05-compatible_pair.pl](chapter-18/05-compatible_pair.pl) ## Chapter 19: Correctness and termination - [01-factorial.pl](chapter-19/01-factorial.pl) — Termination needs its own argument - [02-invalid_limits.pl](chapter-19/02-invalid_limits.pl) — Integrity is not merely failure ## Chapter 20: Improving a program - [01-connected.pl](chapter-20/01-connected.pl) — Strengthen calls before adding machinery - [02-within_thermal_limits.pl](chapter-20/02-within_thermal_limits.pl) — Introduce helpers that express invariants - [03-search.pl](chapter-20/03-search.pl) — Move invariant work outward ## Chapter 21: Reading the computation - [01-grandparent.pl](chapter-21/01-grandparent.pl) — Substitutions accumulate - [02-loop_edge.pl](chapter-21/02-loop_edge.pl) - [03-eligible.pl](chapter-21/03-eligible.pl) — Failure rewinds choices, not facts - [04-grows.pl](chapter-21/04-grows.pl) — Variants, cycles, and tables ## Chapter 22: Trees, languages, and symbolic evaluation - [01-tree.pl](chapter-22/01-tree.pl) - [02-tree_member.pl](chapter-22/02-tree_member.pl) - [03-mirror.pl](chapter-22/03-mirror.pl) — Transforming a tree - [04-evaluate.pl](chapter-22/04-evaluate.pl) — Interpreting an expression - [05-lookup.pl](chapter-22/05-lookup.pl) - [06-simplify.pl](chapter-22/06-simplify.pl) — Rewriting symbolic expressions ## Chapter 23: Transforming programs - [01-adult.pl](chapter-23/01-adult.pl) — Unfolding and folding - [02-adult-2.pl](chapter-23/02-adult-2.pl) - [03-can_board.pl](chapter-23/03-can_board.pl) - [04-traveler_in_good_standing.pl](chapter-23/04-traveler_in_good_standing.pl) - [05-connection.pl](chapter-23/05-connection.pl) — Specializing a relation - [06-rail_connection.pl](chapter-23/06-rail_connection.pl) - [07-sum_numbers.pl](chapter-23/07-sum_numbers.pl) — Accumulators and modes - [08-sum_numbers_acc.pl](chapter-23/08-sum_numbers_acc.pl) ## Chapter 24: Designing finite search - [01-simple_path.pl](chapter-24/01-simple_path.pl) — Search over states - [02-reachable.pl](chapter-24/02-reachable.pl) — Existence, one witness, and all witnesses - [03-best_plan.pl](chapter-24/03-best_plan.pl) — Optimization is search plus an order ## Chapter 25: Case study: an auditable decision service - [01-person.pl](chapter-25/01-person.pl) — Source and concept layers - [02-active_badge.pl](chapter-25/02-active_badge.pl) - [03-in_good_standing.pl](chapter-25/03-in_good_standing.pl) — Closed-world choice - [04-incompatible_status.pl](chapter-25/04-incompatible_status.pl) — Integrity before decisions ## Chapter 26: A proof can be a computation - [01-mortal.pl](chapter-26/01-mortal.pl) - [02-triple.pl](chapter-26/02-triple.pl) — Proof objects and proof checking - [03-edge.pl](chapter-26/03-edge.pl) — The least model as mathematical closure ## Chapter 27: Recursion is induction in motion - [01-natural.pl](chapter-27/01-natural.pl) - [02-list_length.pl](chapter-27/02-list_length.pl) — Structural induction and data design - [03-reverse_acc.pl](chapter-27/03-reverse_acc.pl) — Accumulators and strengthened invariants ## Chapter 28: Algebra, symmetry, and representation - [01-program.pl](chapter-28/01-program.pl) — Unification is structural equation solving - [02-triangle.pl](chapter-28/02-triangle.pl) — Symmetry reduces search - [03-rectangle.pl](chapter-28/03-rectangle.pl) — Relations reveal inverse problems - [04-preserves_combine.pl](chapter-28/04-preserves_combine.pl) — Composition, homomorphism, and reusable laws ## Chapter 29: Search as experimental mathematics - [01-noncommuting_pair.pl](chapter-29/01-noncommuting_pair.pl) — One counterexample has asymmetric power ## Chapter 32: Debugging by meaning, search, and proof - [01-eligible.pl](chapter-32/01-eligible.pl) — Follow bindings from left to right - [02-eligible-2.pl](chapter-32/02-eligible-2.pl) ## Chapter 33: A pattern catalog for reasoning - [01-assigned_badge.pl](chapter-33/01-assigned_badge.pl) — Pattern 1: Ground sentence first - [02-source_role.pl](chapter-33/02-source_role.pl) — Pattern 2: Normalize at the boundary - [03-chosen_pair.pl](chapter-33/03-chosen_pair.pl) — Pattern 3: Generate, constrain, describe - [04-path.pl](chapter-33/04-path.pl) — Pattern 4: Carry the witness - [05-unregistered.pl](chapter-33/05-unregistered.pl) — Pattern 5: Bound absence - [06-step.pl](chapter-33/06-step.pl) — Pattern 6: Explicit state transition - [07-depends.pl](chapter-33/07-depends.pl) — Pattern 7: Fixed-point closure - [08-within_limit.pl](chapter-33/08-within_limit.pl) — Pattern 8: Proof façade - [09-invalid_badge_assignment.pl](chapter-33/09-invalid_badge_assignment.pl) — Pattern 9: Integrity before inference - [10-theory_version.pl](chapter-33/10-theory_version.pl) — Pattern 10: Version the evidence boundary ## Chapter 34: Control, exceptions, and grouped solutions - [01-travel_status.pl](chapter-34/01-travel_status.pl) - [02-require_route.pl](chapter-34/02-require_route.pl) - [03-regional_total.pl](chapter-34/03-regional_total.pl) ## Chapter 35: Reflective terms and atomic conversion - [01-term_shape.pl](chapter-35/01-term_shape.pl) ## Chapter 36: Dynamic predicates, directives, and operators - [01-program.pl](chapter-36/01-program.pl) - [02-program-2.pl](chapter-36/02-program-2.pl) - [03-program-3.pl](chapter-36/03-program-3.pl) ## Chapter 37: Streams and term I/O - [01-write_event.pl](chapter-37/01-write_event.pl) ## Chapter 38: Language and ISO profile - [01-city.pl](chapter-38/01-city.pl)