obitools4/autodoc/docmd/pkg/obiformats/empty_file.md

ReadEmptyFile Function — Semantic Description

• Package: obiformats, part of the OBITools4 ecosystem for biological sequence handling.
• Purpose: Creates and returns an empty, closed iterator over biosequences (IBioSequence).
• Signature:
  func ReadEmptyFile(options ...WithOption) (obiiter.IBioSequence, error)
• Input: Accepts variadic WithOption configuration functions (currently unused in this minimal implementation).
• Behavior:
  • Instantiates a new IBioSequence iterator via obiiter.MakeIBioSequence().
  • Immediately closes the stream using .Close() — indicating no data will be yielded.
• Output:
  • Returns a terminal iterator (no elements), suitable as a safe default or fallback.
  • Error return is always nil, since no I/O occurs and the operation is deterministic.

Semantic Role & Use Cases

• Default/Placeholder: Useful in conditional logic where a valid (but empty) sequence iterator is required when no input file exists or parsing fails.
• Consistency: Ensures callers always receive a well-formed iterator, avoiding nil checks.
• Resource Safety: The closed state prevents accidental iteration or memory leaks.

Design Notes

• Reflects a pure-functional and fail-safe pattern: no side effects, deterministic behavior.
• Aligns with iterator-based I/O design principles in OBITools4 (lazy, composable streams).