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2026-04-07 08:36:50 +02:00
# OBIFormats Package: Semantic Description
The `obiformats` package provides parsing and formatting utilities for **OBI-compliant FASTA headers**, enabling structured annotation of biological sequences.
- It supports parsing key-value annotations embedded in sequence definitions (e.g., `key=value;`), including nested dictionaries.
- Three core parsing functions detect value types:
- `__match__key__`: Identifies assignment patterns (`Key = ...`).
- `__obi_header_value_numeric_pattern__`: Matches floats/integers (e.g., `42.0;`).
- `__obi_header_value_string_pattern__`: Matches quoted strings (e.g., `'example';`).
- `__match__dict__`: Parses balanced `{...}` blocks, handling nested structures and string delimiters.
- Boolean detection (`__is_true__/__is_false__`) handles multiple case variants (e.g., `true`, `True`, `TRUE`).
- The main entry point, **`ParseOBIFeatures(text string, annotations obiseq.Annotation)`,**
iteratively extracts key-value pairs from a header string and populates an `Annotation` map.
- Numeric values are stored as integers if they have no fractional part.
- Dictionary-like strings (e.g., `{'a':1,'b':2}`) are JSON-unmarshalled into typed maps:
- `*_count``map[string]int`,
- `merged_*` → wrapped in a statistics object (`obiseq.StatsOnValues`).
- `*_status`/`*_mutation``map[string]string`.
- **`ParseFastSeqOBIHeader(sequence *obiseq.BioSequence)`** applies parsing to a sequences definition line, moving annotations into its metadata map and preserving leftover text.
- **`WriteFastSeqOBIHeade(buffer *bytes.Buffer, sequence)`** serializes annotations back into OBI header format:
- Strings and booleans use `key=value;`.
- Maps/dicts are JSON-encoded, then single-quoted for compatibility.
- Special handling ensures `obiseq.StatsOnValues` are safely marshalled.
- **`FormatFastSeqOBIHeader(sequence)`** returns the formatted header as a string (zero-copy via `unsafe.String` for performance).
- Designed to interoperate with the broader OBITools4 ecosystem (`obiseq`, `obiutils`), supporting both human-readable and machine-processable sequence metadata.