truefix-core 0.1.0

FIX message model, field types, and SOH codec (BodyLength/CheckSum).
Documentation

truefix-core — FIX message model, field types, and the SOH wire codec.

Provides [Field], [FieldMap], [Group], and [Message] (header/body/trailer), plus [encode]/[decode] that compute and verify BodyLength (tag 9) and CheckSum (tag 10). All parsing returns typed errors and never panics (Constitution Principle I).

Repeating-group structure is modelled here; dictionary-driven group parsing from a flat wire message arrives with truefix-dict (Stage S4). At this layer, decoding yields flat ordered fields, which still round-trips byte-for-byte.

Design: specs/001-fix-engine-parity/.