[FORMAT NAME] Evaluation for MARC Data (Rust Implementation)¶

Issue: mrrc-fks.X Date: YYYY-MM-DD Author: [name] Status: Draft | Complete Focus: Rust mrrc core implementation (primary); Python/multi-language support (secondary)

Executive Summary¶

[2-3 sentences: Is this format viable for MARC data? What are the key findings?]

1. Schema Design¶

1.1 Schema Definition¶

[Native schema format: .proto, .avsc, .fbs, etc.]

1.2 Structure Diagram¶

┌──────────────────────────────────────┐
│ MarcRecord                           │
├──────────────────────────────────────┤
│ leader: string (24 chars)            │
│ fields: [Field]                      │
└──────────────────────────────────────┘
         │
         ▼
┌──────────────────────────────────────┐
│ Field                                │
├──────────────────────────────────────┤
│ tag: string (3 chars)                │
│ indicator1: char                     │
│ indicator2: char                     │
│ subfields: [Subfield]                │
└──────────────────────────────────────┘
         │
         ▼
┌──────────────────────────────────────┐
│ Subfield                             │
├──────────────────────────────────────┤
│ code: char                           │
│ value: string                        │
└──────────────────────────────────────┘

1.3 Example Record¶

[Annotated example of a serialized MARC record in this format]

1.4 Edge Case Coverage¶

For each edge case, test it explicitly with the fidelity test set and document results. All must pass (100%) for recommendation.

Data Structure & Ordering (CRITICAL): | Edge Case | Test Result | Evidence | Test Record | |-----------|-------------|----------|-------------| | Field ordering | ☐ Pass / ☐ Fail | Fields in exact sequence (001, 650, 245, 001 NOT reordered alphabetically/numerically)? | EC-11 | | Subfield code ordering | ☐ Pass / ☐ Fail | Subfield codes in exact sequence ($d$c$a NOT reordered to $a$c$d)? | EC-12 | | Repeating fields | ☐ Pass / ☐ Fail | Multiple 650 fields in same record preserved in order? | EC-8 | | Repeating subfields | ☐ Pass / ☐ Fail | Multiple $a in single 245 field preserved in order? | fidelity set | | Empty subfield values | ☐ Pass / ☐ Fail | Does $a "" round-trip distinct from no $a? | EC-10 |

Text Content: | Edge Case | Test Result | Evidence | |-----------|-------------|----------| | UTF-8 multilingual | ☐ Pass / ☐ Fail | Chinese, Arabic, Hebrew text byte-for-byte match? | | Combining diacritics | ☐ Pass / ☐ Fail | Diacritical marks (à, é, ñ) preserved as UTF-8 (do NOT precompose)? | | Whitespace preservation | ☐ Pass / ☐ Fail | Leading/trailing spaces in $a preserved exactly (not trimmed/collapsed)? | | Control characters | ☐ Pass / ☐ Fail | ASCII 0x00-0x1F in data handled gracefully (error or preserved)? |

MARC Structure: | Edge Case | Test Result | Evidence | Test Record | |-----------|-------------|----------|-------------| | Control field data | ☐ Pass / ☐ Fail | Control field (001) with 12+ chars preserved exactly, no truncation? | EC-13 | | Control field repetition | ☐ Pass / ☐ Fail | Duplicate control fields (invalid—test error handling, not preservation) | EC-14 | | Field type distinction | ☐ Pass / ☐ Fail | Control fields (001-009) vs variable fields (010+) structure preserved? | EC-13, EC-14 | | Blank vs missing indicators | ☐ Pass / ☐ Fail | Space (U+0020) distinct from null/missing after round-trip? | EC-09 | | Invalid subfield codes | ☐ Pass / ☐ Fail | Non-alphanumeric codes ("0", space, "$")—test error handling gracefully | EC-15 |

Size Boundaries: | Edge Case | Test Result | Evidence | |-----------|-------------|----------| | Maximum field length | ☐ Pass / ☐ Fail | Field at 9998-byte limit handled (preserved exactly or clear error)? | | Many subfields | ☐ Pass / ☐ Fail | Single field with 255+ subfields preserved with all codes in order? | | Many fields per record | ☐ Pass / ☐ Fail | Records with 500+ fields round-trip with field order preserved? |

Scoring: Count PASS results. If any FAIL, explain in section 2.2. All edge cases must pass (15/15) for recommendation.

1.5 Correctness Specification¶

Key Invariants: - Field ordering: Must be preserved exactly (no alphabetizing, no sorting, no reordering by tag number) - Subfield code ordering: Must be preserved exactly (e.g., $d$c$a NOT reordered to $a$c$d) - Leader positions 0-3 and 12-15 may be recalculated (record length, base address); all others must match exactly - Indicator values are character-based: space (U+0020) ≠ null/missing - Subfield values are exact byte-for-byte UTF-8 matches, preserving empty strings as distinct from missing values - Whitespace (leading/trailing spaces) must be preserved exactly

2. Round-Trip Fidelity¶

2.1 Test Results¶

Test Set: fidelity_test_100.mrc Records Tested: 100 Perfect Round-Trips: XX/100 (XX%) Test Date: YYYY-MM-DD

2.2 Failures (if any)¶

Record ID	Field	Criterion	Expected	Actual	Root Cause

Failure Investigation Checklist: - [ ] Field ordering changed (fields reordered alphabetically or by tag number)? - [ ] Subfield code order changed (codes reordered, e.g., $a$c$d instead of $d$c$a)? - [ ] Encoding issue (UTF-8 normalization, combining diacritics)? - [ ] Indicator handling (space vs null)? - [ ] Subfield presence missing (wrong count, missing codes)? - [ ] Empty string vs null distinction (empty $a "" vs missing $a)? - [ ] Whitespace trimmed (leading/trailing spaces lost)? - [ ] Leader position recalculation (only 0-3, 12-15 expected to vary)? - [ ] Data truncation (field >9999 bytes)? - [ ] Character encoding boundary issue?

2.3 Notes¶

All comparisons are performed on normalized UTF-8 MarcRecord objects produced by mrrc (fields, indicators, subfields, string values), not on raw ISO 2709 bytes.

[Any format-specific observations about data preservation and edge case handling]

3. Failure Modes Testing¶

REQUIRED: Must complete and pass before performance benchmarking. Formats that panic on invalid input will be rejected.

3.1 Error Handling Results¶

Test the format's robustness against malformed input:

Scenario	Test Input	Expected	Result	Error Message
Truncated record	Incomplete serialized data	Graceful error	☐ Error / ☐ Panic	message or "panic"
Invalid tag	Tag="99A" or empty	Validation error	☐ Error / ☐ Panic	message or "panic"
Oversized field	>9999 bytes	Error or reject	☐ Error / ☐ Panic	message or "panic"
Invalid indicator	Non-ASCII character	Validation error	☐ Error / ☐ Panic	message or "panic"
Null subfield value	null pointer in subfield	Consistent handling	☐ Error / ☐ Panic	message or "panic"
Malformed UTF-8	Invalid UTF-8 bytes	Clear error	☐ Error / ☐ Panic	message or "panic"
Missing leader	Record without 24-char leader	Validation error	☐ Error / ☐ Panic	message or "panic"

Overall Assessment: - ☐ Handles all errors gracefully (PASS) - ☐ Has 1-2 unguarded panics (needs investigation) - ☐ Panics on multiple error cases (FAIL)

4. Performance Benchmarks¶

4.1 Test Environment (Rust Primary)¶

Rust benchmarking environment: - CPU: - RAM: - Storage: - OS: - Rust version: (and rustc optimization level) - Format library version: (Rust crate) - Build command: cargo build --release

Python secondary (if applicable): - Python version: - Library version: - (Only documented if Python bindings evaluated after Rust primary is complete)

4.2 Results¶

Test Set: 10k_records.mrc (10,000 records) Test Date: YYYY-MM-DD Baseline: See BASELINE_ISO2709.md

Metric	ISO 2709	[Format]	Delta
Read (rec/sec)
Write (rec/sec)
File Size (raw)
File Size (gzip)
Peak Memory

4.3 Analysis¶

[Discussion of performance characteristics and comparison to baseline]

5. Integration Assessment¶

5.1 Dependencies (Rust Focus)¶

Rust Cargo dependencies:

Crate	Version	Status	Notes

Total Rust dependencies: X (direct), Y (transitive)

Dependency health assessment: - [ ] All dependencies actively maintained (commits within 6 months) - [ ] No known security advisories - [ ] Compile time impact acceptable (document if >5s incremental build)

5.2 Language Support¶

Language	Maturity	Priority	Notes
Rust	⭐⭐⭐⭐⭐	PRIMARY	Core mrrc implementation
Python	⭐⭐⭐⭐	Secondary	PyO3 bindings (if recommended)
Java	⭐⭐⭐	Tertiary	Ecosystem context
Go	⭐⭐	Tertiary	Ecosystem context
C++	⭐⭐⭐	Tertiary	Ecosystem context

5.3 Schema Evolution¶

Score: X/5

Capability	Supported
Add new optional fields	☐ Yes / ☐ No
Deprecate fields	☐ Yes / ☐ No
Rename fields	☐ Yes / ☐ No
Change field types	☐ Yes / ☐ No
Backward compatibility	☐ Yes / ☐ No
Forward compatibility	☐ Yes / ☐ No

5.4 Ecosystem Maturity¶

[ ] Production use cases documented
[ ] Active maintenance (commits in last 6 months)
[ ] Security advisories process
[ ] Stable API (1.0+ release)
[ ] Good documentation
[ ] Community size / adoption

6. Use Case Fit¶

Use Case	Score (1-5)	Notes
Simple data exchange		API integration, file transfer
High-performance batch		Large-scale processing
Analytics/big data		Spark, Hadoop, Parquet ecosystem
API integration		REST/gRPC services
Long-term archival		10+ year preservation

7. Implementation Complexity (Rust)¶

Factor	Estimate
Lines of Rust code
Development time (estimate)
Maintenance burden	Low / Medium / High
Compile time impact
Binary size impact

Key Implementation Challenges (Rust)¶

3.

Python Binding Complexity (Secondary)¶

PyO3 binding effort estimate:
Additional dependencies:
Maintenance considerations:

8. Strengths & Weaknesses¶

Strengths¶

-¶

Weaknesses¶

-¶

9. Recommendation¶

9.1 Pass/Fail Criteria¶

❌ AUTOMATIC REJECTION if: - Round-trip fidelity < 100% (any data loss whatsoever) - Field or subfield ordering changes (reordering by tag/code is data loss) - Any panic on invalid input (crashes instead of graceful error) - License incompatible with Apache 2.0 - Requires undisclosed native dependencies

✅ RECOMMENDATION REQUIRES: - 100% perfect round-trip on all 100 fidelity test records - Exact preservation of field ordering and subfield code ordering - All edge cases pass (15/15 synthetic tests) - Graceful error handling on all 7 failure modes - 0 panics on any invalid input - Clear error messages for all error cases

9.2 Verdict¶

Select one: - ☐ RECOMMENDED — Format meets all pass criteria; suitable for production use in mrrc - ☐ CONDITIONAL — Format meets fidelity/robustness but has integration concerns (list them) - ☐ NOT RECOMMENDED — Format fails one or more pass criteria

9.3 Rationale¶

[2-3 paragraphs explaining the verdict. Include:] - Fidelity: Summary of round-trip testing (100%, or list any failures) - Robustness: Summary of error handling (all passed, or which scenarios failed) - Performance: How it compares to ISO 2709 baseline (if fidelity/robustness pass) - Ecosystem: Key integration factors (dependencies, build complexity) - Use cases: Where this format excels or falls short

Appendix¶

A. Test Commands¶

# Build
# Run benchmarks
# Validate round-trip

B. Sample Code¶

// Key implementation snippets